tag:blogger.com,1999:blog-9247688141125968272024-03-14T18:29:39.372+08:00Suzy's BlogWooden boatbuilding, Lugged steel bicycle frames, computers. The usual.Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.comBlogger164125tag:blogger.com,1999:blog-924768814112596827.post-79750027221604055332024-01-16T07:51:00.004+08:002024-01-16T07:53:27.490+08:00EmuROM - An Open Hardware ROM emulator<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbCNNrrCxIyHBG09jjlicruNFKt7fYgt5prPre7yr0bHgS1pdSrQ21zpK0uWZhlB8BmPOu_jD8UW6x_PDe7OMtNd7mcIbiMrF70CF7ZdOtqC7131WDHFQF1GVCJbSciv971HDlVNgUr09RQZ5duaNaPEy1F9pln3R3x2eJjnBszABXe0_92_DNF0WJVA/s1280/IMG_4555.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
height="400"
data-original-height="1280"
data-original-width="828"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbCNNrrCxIyHBG09jjlicruNFKt7fYgt5prPre7yr0bHgS1pdSrQ21zpK0uWZhlB8BmPOu_jD8UW6x_PDe7OMtNd7mcIbiMrF70CF7ZdOtqC7131WDHFQF1GVCJbSciv971HDlVNgUr09RQZ5duaNaPEy1F9pln3R3x2eJjnBszABXe0_92_DNF0WJVA/s400/IMG_4555.jpeg"
/></a>
</div>
<p>
Back in the nineties I spent a couple of years doing embedded system design,
plus developing ISA and EISA cards. We had some cool tools for working on
embedded machines, one of which was a ROM emulator. It was a plastic box with
a ribbon cable hanging out one end, and a PC parallel port on the other. You
could remove the ROM from a target system and plug it in, and load the ROM
image into RAM inside the device under control of your PC. It made messing
about with ROMs really straightforward.
</p>
<p>
Anyway, I'm messing about with ROMs now, and find the whole
remove-erase-program-reinsert thing tedious, especially when my EPROM
programmer only works on my old XP machine, which due to it's fragility isn't
networked, which in turn means all my code has to be stuck on a USB stick to
transfer to the programmer.
</p>
<p>
So I went looking online for ROM emulators. I found almost the perfect device,
by <a href="https://github.com/jtsiomb/emurom">John Tsiombikas</a>. A
straightforward board with a little Atmel microcontroller loading a RAM chip
with data, which in turn is gated to the host machine using some tri-state
buffers. Even better, John has released the whole lot under a Free Hardware
and Free Software licence, allowing anyone to take his design work and play
with it as they wish, as long as they in turn release their work under the
same licence. And it's in KiCad!
</p>
<p>
Works for me! I took John's board and started by dropping support for 24 pin
ROMs. If I ever need to emulate 2732's etc, I can aways do another board. As
it's so tiny and I wanted to ensure good signal integrity on the host machine,
I did away with the ribbon cable and mounted it via a 90 degree header and
adapter board directly to the machine. I did a little work on the layout to
reduce the size of the thing and neaten it up, including hiding the host
tri-states under the RAM, which is socketed.
</p>
<p>
In any case, all the design files are on my google drive. I haven't yet
updated the software, but am envisaging extending the firmware a bit so that
no software is needed on the controlling PC aside from a simple terminal
program, with EPROM code downloaded via X-modem, and perhaps even a simple
monitor program. I do most of my work on a Mac, and like to use existing
software (like serial-ii) as much as possible.
</p>
<p>
<a
href="https://drive.google.com/drive/folders/1x4txP8R5QqLANoHnn-FmlKneB_wBMGbX?usp=sharing"
>Here are the files.</a
>
</p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-65376533446495415412024-01-15T06:22:00.005+08:002024-01-15T06:22:37.778+08:00Metcal MX500P soldering iron repair<p>
I've been giving my soldering iron something of a flogging of late. It's a
Metcal MX500P, one of the very finest irons ever to be made. It uses 13.56MHz
RF to heat a teensy inductor right in the tip, with an incredibly ingenious
temperature regulation system whereby a magnet in the tip, once it gets to
temperature, hits it's Curie point and loses magnetism, changing the frequency
the coil resonates at and thus making it get more or less hot with the applied
13.56 MHz. In any case, yesterday it simply stopped getting hot. I found an
extremely good on-line analysis of the soldering iron
<a href="http://colinoflynn.com/wp-content/uploads/2012/05/MX-500P-11.pdf"
>here.</a
>, and mention of dead driver transistors. in forums.
</p>
<p>
In any case, I opened it up and had a look, and there was a pretty obvious
popped capacitor:
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbRikEeuLmqXyZkudy1naDD6bO96NfdbREb9dt9YTV_3cZHLy-sNSJ3ZEaDEg3BHQpi0NlYK3OhNbJSi1Uxgha19uXfUW8lgpGygSZAPbll3Q4XAlYtZALYelwThuWdPxQpN1dtLLG-2m0wofWbFi6_5tsTDrRM2guU9idoNrjbILTJSdaaC4G5e5OVw/s1280/IMG_2974.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="400"
data-original-height="960"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbRikEeuLmqXyZkudy1naDD6bO96NfdbREb9dt9YTV_3cZHLy-sNSJ3ZEaDEg3BHQpi0NlYK3OhNbJSi1Uxgha19uXfUW8lgpGygSZAPbll3Q4XAlYtZALYelwThuWdPxQpN1dtLLG-2m0wofWbFi6_5tsTDrRM2guU9idoNrjbILTJSdaaC4G5e5OVw/s400/IMG_2974.jpeg"
/></a>
</div>
<p>
It's C4, a 330n 63V film cap that just does smoothing on a DC rail. Here it is
after removal:
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1PWfWmgu3YNONbkDvWtLXzh6kLRCYBZb6ahfHGZUv9HO-O_WJ9jHebbAJ2SmzpWjfpsya5Hcf7iL9JCtM3uPJb6rODVFOQrcAAfWHcM9_WQ8fxPbfGPSVDRKpv4K6CAW_O2LXJugu7L22Wt_wRRudhdh0FQLeUexOOGydtcxHC97CyW5dZNPTRzKIvA/s1280/IMG_2975.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="400"
data-original-height="932"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1PWfWmgu3YNONbkDvWtLXzh6kLRCYBZb6ahfHGZUv9HO-O_WJ9jHebbAJ2SmzpWjfpsya5Hcf7iL9JCtM3uPJb6rODVFOQrcAAfWHcM9_WQ8fxPbfGPSVDRKpv4K6CAW_O2LXJugu7L22Wt_wRRudhdh0FQLeUexOOGydtcxHC97CyW5dZNPTRzKIvA/s400/IMG_2975.jpeg"
/></a>
</div>
<p>I replaced it with a 330n 100V one, and voila.</p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-62778297806647007782024-01-06T07:37:00.005+08:002024-01-21T16:58:10.984+08:00FreeBee Premium<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuUjhoRnD3SiKrCiRD8m6uwBBRyPR5EdplyoaNNkazGP2sdZ8PJmdIwAjU9lX5wUErh4FeXp5QlHA2dDXvnk1SHdrdZ1KZIwTsqfTi1LLmBvL5gWN9eQ8XAJQNZYuVBBzrMneeggsgFNflmNpnl2d5qf7sanTB0ZUykmnDbIFHn4zp7Z9AddOsflBanQ/s3092/Screenshot%202024-01-21%20at%204.24.27%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2202" data-original-width="3092" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuUjhoRnD3SiKrCiRD8m6uwBBRyPR5EdplyoaNNkazGP2sdZ8PJmdIwAjU9lX5wUErh4FeXp5QlHA2dDXvnk1SHdrdZ1KZIwTsqfTi1LLmBvL5gWN9eQ8XAJQNZYuVBBzrMneeggsgFNflmNpnl2d5qf7sanTB0ZUykmnDbIFHn4zp7Z9AddOsflBanQ/s600/Screenshot%202024-01-21%20at%204.24.27%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk1tGBPLGoSvM3p5u_zik-YYbrys-aja6KABGYh2vSel-p_7GQ55Eyc2st3jttUF3qlCbU2rzQ1y1mO18dv5wLNMKyQ0-B0nDSmfS7_4NoM10zt2aVF2EJplnAcrkYe_KXLyMsGO8_wHXjq6EUcvpHao6JnO0Bn066HY_n6lXx3CRmaRI6Z05pDwtDvw/s1724/Screenshot%202024-01-21%20at%204.38.30%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1724" data-original-width="1250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjk1tGBPLGoSvM3p5u_zik-YYbrys-aja6KABGYh2vSel-p_7GQ55Eyc2st3jttUF3qlCbU2rzQ1y1mO18dv5wLNMKyQ0-B0nDSmfS7_4NoM10zt2aVF2EJplnAcrkYe_KXLyMsGO8_wHXjq6EUcvpHao6JnO0Bn066HY_n6lXx3CRmaRI6Z05pDwtDvw/s600/Screenshot%202024-01-21%20at%204.38.30%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7KvKVTN0bzFjHahaiwxdkSa3idNAtlwF6iEmKCZSvEWKUQK5pyCCmc8ZUSTZ9d-gzAjpxBfByQYBHhsdUZDvA99pw1GiK_4whzbP50dXJBbrAdztCOdpNmgeJFIrtky0lGzlHjdpTimQ4T-R40a635xbeRkgRpthEo8wWD6b2_1HcBzTdHQh1rVXzgQ/s3096/Screenshot%202024-01-21%20at%204.38.51%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1732" data-original-width="3096" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7KvKVTN0bzFjHahaiwxdkSa3idNAtlwF6iEmKCZSvEWKUQK5pyCCmc8ZUSTZ9d-gzAjpxBfByQYBHhsdUZDvA99pw1GiK_4whzbP50dXJBbrAdztCOdpNmgeJFIrtky0lGzlHjdpTimQ4T-R40a635xbeRkgRpthEo8wWD6b2_1HcBzTdHQh1rVXzgQ/s600/Screenshot%202024-01-21%20at%204.38.51%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilRdL7bhcmldHRZ83T4izgMS6WaGT_Y6F9xz4Ej_Rdc4s3Aa5JBnirHivj4EkojR3PebwfN70-eN_FFGSZLQIuyyOJvJuCIKE4fFVNbw_ZY_6aGLqT1PiavUDIWSRxna95-hWc4xn2QvtuvscKUsKHs8EobiqFYgpcx85K_nCLoC6WjS6p0Yao9GIfvg/s1794/Screenshot%202024-01-21%20at%204.39.17%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1794" data-original-width="1408" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilRdL7bhcmldHRZ83T4izgMS6WaGT_Y6F9xz4Ej_Rdc4s3Aa5JBnirHivj4EkojR3PebwfN70-eN_FFGSZLQIuyyOJvJuCIKE4fFVNbw_ZY_6aGLqT1PiavUDIWSRxna95-hWc4xn2QvtuvscKUsKHs8EobiqFYgpcx85K_nCLoC6WjS6p0Yao9GIfvg/s600/Screenshot%202024-01-21%20at%204.39.17%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtgGS7AvqasfLEhM9-Q-nvhnW9Do0esWoPedww9Zfwcyvd7X6WSAT3iJEURzuFyqQghXsyoN5xXHxHvYC9Ti-ECB-af8hAuDSVXXmR_oREF4UJ4XZ-DYvNChA-ilR6hcpuUSeqoZ7KX6kIGG6cegVXsM7sDEf1FuRsYCAFD64W8AnMqpyCpt5zve4spA/s1684/Screenshot%202024-01-21%20at%204.39.44%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1684" data-original-width="1220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjtgGS7AvqasfLEhM9-Q-nvhnW9Do0esWoPedww9Zfwcyvd7X6WSAT3iJEURzuFyqQghXsyoN5xXHxHvYC9Ti-ECB-af8hAuDSVXXmR_oREF4UJ4XZ-DYvNChA-ilR6hcpuUSeqoZ7KX6kIGG6cegVXsM7sDEf1FuRsYCAFD64W8AnMqpyCpt5zve4spA/s600/Screenshot%202024-01-21%20at%204.39.44%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdFGueb93DlKS6AREDb0IaD-QNIqSUqEI0NNkYwQwoCaHGSLmtR-dSW8NcxHGavU7p0vktccOgOEzEEUmaNdaCjd178FBrGSbVgIDvs42Bbgsyr16n7M7yGUHyTklpjgMp52YxZXdNOyaq50JBDCFttNN6W2rmXrParH69XYv2TwMMLG-UNfgffXeqKQ/s1120/Screenshot%202024-01-21%20at%204.39.58%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1120" data-original-width="998" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdFGueb93DlKS6AREDb0IaD-QNIqSUqEI0NNkYwQwoCaHGSLmtR-dSW8NcxHGavU7p0vktccOgOEzEEUmaNdaCjd178FBrGSbVgIDvs42Bbgsyr16n7M7yGUHyTklpjgMp52YxZXdNOyaq50JBDCFttNN6W2rmXrParH69XYv2TwMMLG-UNfgffXeqKQ/s600/Screenshot%202024-01-21%20at%204.39.58%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7HNYHkpRms0VO9eeMM9oTnn5HxqhPmGPVEd9jx05WJ16_TXUmhIdDB6ZaNcduOPH0feeJ4vV3cV8Wqa9TIf4QSfNEuJPP7r0QAdYVK1_GdAC5lHwjOnoTcV60UkJLD5MYpl2DeQQZ5GTEFDLf-Qkz-MkTndbNTiUPq-i1V-LK3vGG4UXo-p5G6ujPCg/s2294/Screenshot%202024-01-21%20at%204.40.21%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2294" data-original-width="1894" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7HNYHkpRms0VO9eeMM9oTnn5HxqhPmGPVEd9jx05WJ16_TXUmhIdDB6ZaNcduOPH0feeJ4vV3cV8Wqa9TIf4QSfNEuJPP7r0QAdYVK1_GdAC5lHwjOnoTcV60UkJLD5MYpl2DeQQZ5GTEFDLf-Qkz-MkTndbNTiUPq-i1V-LK3vGG4UXo-p5G6ujPCg/s600/Screenshot%202024-01-21%20at%204.40.21%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXgTdN9uU0_esz99mZ9dwvO0z8j-CxIPcCGVMqi40aRMv0gUMQJRoBKeWhPTAWvaMPVZXZmJiIccuCjLYI9ilyj9gcvPrnN-V-YAIK_4dptVHZY7e8dDrlWO9aTP1evCyOFyMcTqelg5GjErANR9ostIUx9BS0BPgBCs0VpuyfeWJaTxbDtySGHnpeLQ/s1790/Screenshot%202024-01-21%20at%204.40.38%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1790" data-original-width="1096" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXgTdN9uU0_esz99mZ9dwvO0z8j-CxIPcCGVMqi40aRMv0gUMQJRoBKeWhPTAWvaMPVZXZmJiIccuCjLYI9ilyj9gcvPrnN-V-YAIK_4dptVHZY7e8dDrlWO9aTP1evCyOFyMcTqelg5GjErANR9ostIUx9BS0BPgBCs0VpuyfeWJaTxbDtySGHnpeLQ/s600/Screenshot%202024-01-21%20at%204.40.38%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDzPJsVDotz5F2PofgFdW_jhHRyiKF0O50oZ2pBsSJu6nhYX_Ip8HJ5E3o0nJjmXSJYSP9ArN7V1noab0hWMYU9IvEJYZngc5eVWCCLuA816RhaS_zWbztdIW5ZtAjpwTDWqrAhm1R6nU5eJyUQeTJu0cBEKclH_8aDxvj2ve5WlZl2cbS1BvKpI5Ing/s904/Screenshot%202024-01-21%20at%204.40.51%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="468" data-original-width="904" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDzPJsVDotz5F2PofgFdW_jhHRyiKF0O50oZ2pBsSJu6nhYX_Ip8HJ5E3o0nJjmXSJYSP9ArN7V1noab0hWMYU9IvEJYZngc5eVWCCLuA816RhaS_zWbztdIW5ZtAjpwTDWqrAhm1R6nU5eJyUQeTJu0cBEKclH_8aDxvj2ve5WlZl2cbS1BvKpI5Ing/s600/Screenshot%202024-01-21%20at%204.40.51%20pm.png"/></a></div>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXY9UR067HcEF_Z6ifw-XFDcMyyyWgGrUEALsV54BZWVUx3cuOtGzTvIgxFrGAgmfy74-MFtDPfhxT2LUaS6IM2UFF-qbsRYz0_mk25FEVdm5tC547Z0INZeJMaGs2W3m8UCogv9X4iRLZor5Y_jhMqlUI2ZSbNqmwuroum0ruQfLcGisddy-lVtX2HQ/s1558/Screenshot%202024-01-21%20at%204.57.19%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1558" data-original-width="1320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXY9UR067HcEF_Z6ifw-XFDcMyyyWgGrUEALsV54BZWVUx3cuOtGzTvIgxFrGAgmfy74-MFtDPfhxT2LUaS6IM2UFF-qbsRYz0_mk25FEVdm5tC547Z0INZeJMaGs2W3m8UCogv9X4iRLZor5Y_jhMqlUI2ZSbNqmwuroum0ruQfLcGisddy-lVtX2HQ/s600/Screenshot%202024-01-21%20at%204.57.19%20pm.png"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-60684011200881082732023-12-24T12:22:00.027+08:002024-01-29T06:24:00.831+08:00Making the Compact Flash Coreboard more accessible (and reliable!)<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggOZQqwkzsRx3TguU7QHJwla_7xIaqVYeGi6wz7pAkrCks7iV2S4VnAdn05OanM_dKYsRojyydZ-hnIH2axX0zMGVkEawtOKVnr16kaQl_veRtmlhwufqjAAazROv9iJE3K6OdM2MQlPQPzkqpqri2Ef6MIlxO81vyCV68WwVXVsGzfL-aSpUW3fHaIA/s2876/Screen%20Shot%202023-12-30%20at%2010.59.41%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1188" data-original-width="2876" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggOZQqwkzsRx3TguU7QHJwla_7xIaqVYeGi6wz7pAkrCks7iV2S4VnAdn05OanM_dKYsRojyydZ-hnIH2axX0zMGVkEawtOKVnr16kaQl_veRtmlhwufqjAAazROv9iJE3K6OdM2MQlPQPzkqpqri2Ef6MIlxO81vyCV68WwVXVsGzfL-aSpUW3fHaIA/s600/Screen%20Shot%202023-12-30%20at%2010.59.41%20am.png"/></a></div>
<p>
I really enjoyed the design exercise for the FreeBee main board, especially
doing the whole thing without using any PLDs. It had me drawing Karnaugh maps
and trying different methods of simplifying TTL logic, which I find really
satisfying.
</p>
<p>
So over the Christmas break I figured I'd revisit an older project, the
Compact Flash Coreboard. Last time I worked on this was back in 2016. It
basically featured a compact flash socket, some RAM, ROM, Floppy controller,
and three Atmel 44 pin CPLDs. The design of these CPLDs was an exercise in
frustration, tracking down glitches everywhere due to the big difference in
their speed compared to that of the Microbee that was running them. One of the
key issues was that I convinced myself that in order to talk IDE, I needed to
do 16 bit transfers, where this simply isn't the case. This greatly complicated
the design.Recently however I've been reading of RCBUS designs, including a
compact flash interface in just three TTL chips (see
<a href="https://www.vtsys.pl/interface-compact-flash/">this work by Tadeusz Pycio</a>)
that corrects for timing differences between the Z80 (rd, wr,
iorq) and 8086 (iord, iowr) bus, meaning it will work reliably with any
smallish Flash card, not just a select few.
</p>
<p>
The board essentially replicates what my old rev 0.4 coreboard did, with up to 512K of RAM, up to 512K of EEPROM, a floppy disk controller, and the Compact Flash interface. It's the "I want to have the CP/M bee experience" equivalent of the SuperPAK coreboard.
</p>
<p>
By allowing for up to 512K of EEPROM, my hope is that the machine can run a ported version of ROMWBW, which is an unencumbered version of CP/M developed by the retrocomputing community.
</p>
<p>
IC13, a 74HCT138, performs port decode into 8 port chunks, from P40h-47h, through to
port 78h-7Fh.
<p>
Bank switching is performed to allow up to 512K of RAM
and 512K of EPROM on the Microbee or FreeBee mainboards, in a way that works
with the standard Microbee BIOS. This involves a write-only port at 50h, with
the following bit assignments:
</p>
<list>
<li>Bit 0: RAM bank bit 0
<li>Bit 1: RAM bank bit 1
<li>Bit 2: Video RAM disable. When reset video memory is given precedence in
the map over all other memory.
<li>Bit 3: ROM disable. When set RAM bank 0 appears in upper memory (8000h - FFFFh)
and bit 1 is negated.
When reset ROM bank zero appears in upper memory.
<li>Bit 4: Video RAM location. When reset video RAM is at F000h to FFFFh.
When set it is from 8000h to 8FFFh.
<li>Bit 5: ROM bank select. When set we can use the four bank bits to select a ROM
bank to appear in lower memory (0000h to 7FFFh) when ROM is enabled. When set the
RAM exists here. Note this leaves no RAM in the system except for Video RAM.
This bit breaks compatibility with the bee bank scheme when set, but shouldn't
matter as I've never seen it used.
<li>Bit 6: RAM bank bit 2.
<li>Bit 7: RAM bank bit 3.
</list>
<p>
There's a bit of weirdness with the Microbee bank select that we have to account
for as well. Essentially bank select bit 1 is exclusive ORed with ROM disable. I'm
not completely sure why they did this, and it's really hard to figure out from the
contradictory documentation. When the computer boots and the register is cleared,
RAM bank 0 appears from 0000h to 7FFFh, ROM bank 0 from 8000h to EFFFh, and video
memory from F000h to FFFFh. Setting bit 2 then sees RAM bank 2 from 0000h to 7FFFh,
RAM bank 0 from 8000h to EFFFh, and video memory from F000h to FFFFh.
</p>
<p>
The compact flash interface is composed of just two dedicated chips, IC26 and IC28.
IC26B, a 74HCT32, creates a shortened IORD* pulse by delaying the start of RD* by one
CPU clock. IC26A lengthens CFSEL* by a CPU clock. The two gates on IOWR* simply delay
this signal by two gate delays.
</p>
<p>
The compact flash and IDE interface exists from P60h to P68h. This maintains
compatibility with the Microbee CF8 BIOS.
</p>
<p>
The reset circuit is straight from the standard SRAM coreboard. Note thet we are not
asserting NMI instead of reset with jump latch, as they do for the Microbee DRAM
coreboards. I believe this is done to ensure refresh is continued to the RAM. As we're
not using DRAM, we don't need to do this. As with the SuperPAK board, some adjustment
of D4 might be necessary depending on what supply voltage you run your bee on.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVzQ5LKv7weVtz1l_OUGZ1oTnJbDDq9JV0NQJraSZEbWH3pauS4oP9ZrlWGdP6Ny94yB7-6ZIMsDAupGjruBeAjCJdnCia7N9AFmKvQnQaUydU1OMT885o8iCquz7MiwCPWK3nwNsIQtAz9WUflIUc85OEfuNqApckQgVxLZzvSwKUEc_Z9vzJ3xkJDA/s3128/Screen%20Shot%202023-12-30%20at%2011.01.49%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2178" data-original-width="3128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVzQ5LKv7weVtz1l_OUGZ1oTnJbDDq9JV0NQJraSZEbWH3pauS4oP9ZrlWGdP6Ny94yB7-6ZIMsDAupGjruBeAjCJdnCia7N9AFmKvQnQaUydU1OMT885o8iCquz7MiwCPWK3nwNsIQtAz9WUflIUc85OEfuNqApckQgVxLZzvSwKUEc_Z9vzJ3xkJDA/s600/Screen%20Shot%202023-12-30%20at%2011.01.49%20am.png"/></a></div>
<p>
The rest of the board is the Floppy Disk Interface. This is really only interesting
if you have old floppy disks to read. There are a pile of changes from the
"standard" microbee floppy interface. Firstly, The board should work (with some code
changes) for either WD2793 or WD2797 FDC chips. This is done by not using the ENMF*
input (WD2793) to do a divide by two on the clock. This is instead done separately
using a flipflop.
</p>
<p>
IC15 is a four bit latch at port 48h. Bit 0 selects the floppy drive (A or B). Bit 2
selects the side. Bit 3 is used to select double density (MFM encoding) on the FDC.
Bit 4 (unused on the microbee normally) selects high density (8", 5.25" 1.2MB, or 3.5"
1.44MB) disks. When set it doubles the FDC clock, and selects a different set of
precompensation trimpots, as well as doubling the pump frequency (by halving the
capacitance on the pump pin. This is based on the FloppyIO board from
<a href="https://microbee-mspp.org.au">MSPP</a>.
</p>
<p>
There's some jumpers for selecting Head Load Timeout delays. I've labelled them 3
(fast), 5 (medium) and 8 (glacial) to correspond to the varying delays that must be
incorporated for various hardware.
</p>
<p>
The last tidbit from the FDC sheet is the NMI logic. The microbee is not fast enough
normally to keep up with the data rate from a high density drive. Tony Ellis did a
lot of work to develop a faster FDC interface, and worked out that if you use the INTRQ
output from the FDC to trigger an NMI and heavily optimise your code, you can _just_
keep up at 3.375 MHz.
</p>
<p>
So IC20D, IC18A, and IC23B does that. When HD floppies are enabled and halt is active
(ie the CPU is waiting for an interrupt), the INTRQ or DRQ output of the FDC is gated
to NMI.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSo5hDNXoYH0O54K2MQFPuh2T7dJPLqEuMUv6vf3si0GSOD20tywwl3AlaAZaMjOkNiiOXau2OJd3cmSr2mm01wDPvS6tv3c6BcReDZJY8BeMYPgkUukfDW4lu55nbAKETxwmCCPMKwjjjffCGLVWSdOorgLuNl-wB1RXsFOM37IOj82NwRJzrrVk3pQ/s3250/Screen%20Shot%202023-12-30%20at%2011.03.05%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2242" data-original-width="3250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSo5hDNXoYH0O54K2MQFPuh2T7dJPLqEuMUv6vf3si0GSOD20tywwl3AlaAZaMjOkNiiOXau2OJd3cmSr2mm01wDPvS6tv3c6BcReDZJY8BeMYPgkUukfDW4lu55nbAKETxwmCCPMKwjjjffCGLVWSdOorgLuNl-wB1RXsFOM37IOj82NwRJzrrVk3pQ/s600/Screen%20Shot%202023-12-30%20at%2011.03.05%20am.png"/></a></div><p>
The PCB design is a simple 269 x 107mm, two layer board. The Compact flash socket
dictates 8 thou (0.2mm) clearance, but otherwise it's much the same as other FreeBee
boards. I've taken a lot of care to get grounds low impedance, and added a 40mm IDE
socket, so if you're not brave enough to solder on the 0.635mm pitch SMD Compact
Flash socket, you can just buy a cheap eBay adapter and use thet.
</p>
<p>
It's part of the FreeBee family, so has been treated to the same attention to detail
as other boards from the family. Nice rounded tracks and a clean hand-done layout,
with generous elliptical pads for all ICs making for ease of construction.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidfP3ZI8RVXREEGt1_vti5kTPhKiZX5WCZ5F_Abf0OVw72XbURXEjibiKFyyz1Dqa4o32-52ll3JDua_YfaBqzX17dNTY5YtFAZJFASlUriijJwt3wx0xOX5Ehfn_QRMRQgbTEXMRxwmcXgw2PhzXf-SoVe8aNWf4VLOFJvaA64Sx44Q14kfRtcLNZSg/s2874/Screen%20Shot%202023-12-30%20at%2011.00.50%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1182" data-original-width="2874" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidfP3ZI8RVXREEGt1_vti5kTPhKiZX5WCZ5F_Abf0OVw72XbURXEjibiKFyyz1Dqa4o32-52ll3JDua_YfaBqzX17dNTY5YtFAZJFASlUriijJwt3wx0xOX5Ehfn_QRMRQgbTEXMRxwmcXgw2PhzXf-SoVe8aNWf4VLOFJvaA64Sx44Q14kfRtcLNZSg/s600/Screen%20Shot%202023-12-30%20at%2011.00.50%20am.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia17uqgjAbSd5Ke1YSHqPaQDS0yLZ3p7iULbT68n64Lu4VB6-JsMDTC2Iz45K69Uez-kctFbg1NrlxUtI7rgsmoKD1acHcJmTuGatRcN2i1I9hrEFm3RPBkR5tL5uEgGF-fhCus-33NRxNdqr2Rd46vgqirNF_zqktiz48G-53Dv72OINOyiKKghci-Q/s2866/Screen%20Shot%202023-12-30%20at%2011.01.06%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1170" data-original-width="2866" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEia17uqgjAbSd5Ke1YSHqPaQDS0yLZ3p7iULbT68n64Lu4VB6-JsMDTC2Iz45K69Uez-kctFbg1NrlxUtI7rgsmoKD1acHcJmTuGatRcN2i1I9hrEFm3RPBkR5tL5uEgGF-fhCus-33NRxNdqr2Rd46vgqirNF_zqktiz48G-53Dv72OINOyiKKghci-Q/s600/Screen%20Shot%202023-12-30%20at%2011.01.06%20am.png"/></a></div>
<p>
It's a completely open source design. Design files are <a href="https://drive.google.com/drive/folders/1E3AuC_tRDqrwD-ljtdEtjx7Hx3VskbEk?usp=share_link">on my Google drive.</a> Having gotten the prototype working, I'm in the process of updating the design files for the production version.
</p>
<p>
Here's the prototype ready for smoke test...
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRFKkTsFGqzpKTiUny3aHcSnyZQLQ-tZdSSrDzvam8ajX9kcmM1CzmZqv_Eb3kA1v4avUVYYhYfSX5BWt8BasD_df3FRd9MSpnvP7HlNwRWbviSaFq1_5AZ6eojlfi7ppzxbHUIDW6TpUirrT89Mliqv-MClD7NCmVxAlwd5zuqrGgwxPSalwxCQTLYA/s1280/IMG_4563.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRFKkTsFGqzpKTiUny3aHcSnyZQLQ-tZdSSrDzvam8ajX9kcmM1CzmZqv_Eb3kA1v4avUVYYhYfSX5BWt8BasD_df3FRd9MSpnvP7HlNwRWbviSaFq1_5AZ6eojlfi7ppzxbHUIDW6TpUirrT89Mliqv-MClD7NCmVxAlwd5zuqrGgwxPSalwxCQTLYA/s600/IMG_4563.jpeg"/></a></div>
<p>
There are two small stuff-ups with the prototype. Firstly I forgot to connect the video enable signal back to the coreboard connector. A bodge wire is needed from IC16 pin 4 to X4 pin 13. Secondly the drive A and Drive B select signals are reversed.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfeFrQ6TQUeCwcmyHh-DLcRtuUwWcQ_vYiq0hm76x0lh6TszhN00Gi-TjblEV8qn_C48EsW97hflx09rhq37eR6JzbYbLaV1rzttTIzRWxlA6roxV6giLDcCrrKSQj0xe8FzZ6V-maMujR8NcokWLBGrfzz1QShWYPoQcM9tswE3SPYgXtcCrHr20-rQ/s1280/IMG_4564.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1280" data-original-width="960" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfeFrQ6TQUeCwcmyHh-DLcRtuUwWcQ_vYiq0hm76x0lh6TszhN00Gi-TjblEV8qn_C48EsW97hflx09rhq37eR6JzbYbLaV1rzttTIzRWxlA6roxV6giLDcCrrKSQj0xe8FzZ6V-maMujR8NcokWLBGrfzz1QShWYPoQcM9tswE3SPYgXtcCrHr20-rQ/s600/IMG_4564.jpeg"/></a></div>
<p>There is a process documented on the MSPP site for generating the CF images to work with this, as well as the BIOS ROM, in the <a href="https://www.microbee-mspp.org.au/extplorer_mspp/index.php">"tech"</a> repository, under Microbee/Software/Compact_Flash/IDE_CF_Adapter.</p>
<p>Disk controller setup is as follows:</p>
<p>Boot into monitor with ctrl-M (no CF card installed).</p>
<p>Install a jumper across the TEST header (This has to be done after boot).</p>
<p>In monitor type O 48 8. This will enable DDEN mode, but keep HDEN mode disabled.</p>
<ul>
<li>Check the clock frequency (pin 24 IC19), it should be 1 MHz.</li>
<li>Adjust RV4 to make the pulse on the TG43 test point 500ns.</li>
<li>Adjust C23 to make the pulse on the DIRC test point 2µs.</li>
<li>Adjust RV2 to make the pulse on the WD test point 250ns.</li>
</ul>
<p>
Now type O 48 18 in monitor. This enables HDEN mode, as well as DDEN mode.
</p>
<ul>
<li>Check the clock frequency (pin 24 IC19), it should be 2 MHz.</li>
<li>Adjust RV3 to make the pulse on the TG43 test point 250ns.</li>
<li>Check that the pulse length on DIRC is now 1µs.</li>
<li>Adjust RV1 to make the pulse on the WD test point 125ns.</li>
</ul>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-37416734188107071592023-10-30T15:48:00.014+08:002024-01-19T07:19:13.800+08:00FreeBee - A Microbee Compatible Single Board Computer<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfb0kyC_9Vg7uUa5pCxoic-YtaFPsEDf2WcE89zC9hqyVoxO1gFHw6ocXzZ1wtY-FyI-2Haop-BDYJO0L86r2fharfJY9NKUR7ZzVlUSE28YprmZavhRvS3XkDKS7oxwyPafd5CsbB1SWZwn6SJIFqk5o0k_zEaCWtSbWHgRRRlW3lbsIf3z4qP0qqSQ/s1280/IMG_4562.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="400" data-original-height="1280" data-original-width="960" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfb0kyC_9Vg7uUa5pCxoic-YtaFPsEDf2WcE89zC9hqyVoxO1gFHw6ocXzZ1wtY-FyI-2Haop-BDYJO0L86r2fharfJY9NKUR7ZzVlUSE28YprmZavhRvS3XkDKS7oxwyPafd5CsbB1SWZwn6SJIFqk5o0k_zEaCWtSbWHgRRRlW3lbsIf3z4qP0qqSQ/s400/IMG_4562.jpeg"/></a></div>
<p>
This one is perhaps a little more ambitious than most of my vintage comupting shenanigans. It's been rattling around my head
for a good number of years, as a vague idea about how I could simplify the video hardware on a Microbee. It's had a few false
starts - mainly because as soon as the design process starts I start adding things - Z180 processors, per-pixel colour, blah blah.
Once I start designing PLDs in, I know it's not going to see the light of day, as I simply don't enjoy the PLD design process.
</p>
<p>
So this time around I set myself some really strict rules. I wanted to design the least possible computer I could that's capable
of running Emu Joust. Rules are:
</p>
<ul>
<li>All through-hole DIP.</li>
<li>Must be able to play Emu Joust.</li>
<li>Absolutely no PLDs. Really. Designing a PLD in is just a shorthand to saying "I couldn't bother doing that bit, I'll leave
it for later". And the bloody things just raise the bar for everyone. So many products use a PLD simply to make them hard to
copy.</li>
<li>Which brings me to the next bit. Open source.</li>
<li>A machine for validating my video memory scheme.</li>
<li> as much as possible built from easy to obtain, current production chips.</li>
</ul>
<p>The last point is a bit difficult, as the key component for running Microbee software is the R6545 CRT controller. This is the
granddaddy of modern graphics processors. It doesn't actually touch the graphics information, but it contains a pile of highly
configurable counters that generate all the addresses for working theough video memory and pushing the data out to a CRT.
</p>
<p>
It's the "highly configurable" bit that's problematic. Other machines of a similar era, even those that used ASICs for video
(like the Sinclair Spectrum) had counters to clock through video memory, but were's nearly as configurable as the 6545. This
is why the Harlequin is able to do Spectrum video in TTL. No configurability. Anyway, yes, 6545's aren't in current production,
but we'll just have to deal with that.
</p>
<p>
So let's get this video memory scheme bedded down first. It's the core part of the desigh. The majority of the computer is the
video display circuitry.
</p>
<p>
The R6545, like it's very close relative the Motorola 6845, comes from the bad old days of computing when people were impressed by
seeing characters on a screen. Nowadays computers have pixel-addressable screens, but back in the late seventies that was super-
high-end. When you think of the amount of data that even the modest Microbee 512 x 256 screen resolution entails (16kB in glorious
monochrome), and then imagine moving the whole screen up one line (like you would when you scroll) with an LDIR block copy command.
This takes 21 clocks per byte, or a whopping 6.2µs at 3.375 MHz. Our screen takes 101ms to draw (much longer if we have to wait
for retrace times to do our moving), and the CPU isn't doing _anything_ else during that time.
</p>
<p>
So the whole character thing makes our lives simpler. If we base our display on ASCII, and split the display up into (say) 16 rows
of 64 columns (like the Bee does) then we've only got 1kB of data to store (and move!) for the whole screen.
</p>
<p>
The key to character based screens is a double memory access. The CRTC outputs a counter that points to the character position on
the screen. Each character is made up of a number of rows, and the CRTC outputs a row address that indexes into a character ROM.
The same people who made the CRT Controllers also sold ROMs with ASCII character data.
</p>
<p>
Here's a diagram from the SY6545 application note showing the scheme:
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnc7wqMOTx-XDrvECROb-h3u66PlHkG4DsdxLTYpaGuMKz1ukszHdqiyAijNZaN6V2S76NKQizzhdxlsIyHMI5AqMoyqnGF62rhxFwoVHP1BVLDaY3zJGnD2SY66608N5yReiJ1xhNh83lyhOc_sTIcTwuxCT7nv5zgR6hJCodPyBj6jGfyPIXK4JHDg/s2132/Screen%20Shot%202024-01-02%20at%2012.45.01%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="400" data-original-height="1092" data-original-width="2132" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnc7wqMOTx-XDrvECROb-h3u66PlHkG4DsdxLTYpaGuMKz1ukszHdqiyAijNZaN6V2S76NKQizzhdxlsIyHMI5AqMoyqnGF62rhxFwoVHP1BVLDaY3zJGnD2SY66608N5yReiJ1xhNh83lyhOc_sTIcTwuxCT7nv5zgR6hJCodPyBj6jGfyPIXK4JHDg/s400/Screen%20Shot%202024-01-02%20at%2012.45.01%20pm.png"/></a></div>
<p>
And here's what's in the character ROM. This little guy is the Motorola MCM66740, from the late seventies. If you've spent as
long looking at Microbee screens as I have, this will be instantly recognisable. It's the 'bee font!
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1dYCqoOvXqTiCMUcB3nU-F9wxWOhNs6nP5XVngB4HVaVqse8KfKbBVyO5m7xAH3H5rMTbTeNGHh4FsMo1axw4H8PlZcm1hp6d8pzIVfBhR-ZzHAN20YzoBhfWobmKs2UN1vq15GvPPC_eaIgAqBleJi_XO4nPI5i4-Gs3QlX9mV34mFlAIjAQTqZFHQ/s1890/Screen%20Shot%202024-01-02%20at%2012.37.41%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="400" data-original-height="1244" data-original-width="1890" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1dYCqoOvXqTiCMUcB3nU-F9wxWOhNs6nP5XVngB4HVaVqse8KfKbBVyO5m7xAH3H5rMTbTeNGHh4FsMo1axw4H8PlZcm1hp6d8pzIVfBhR-ZzHAN20YzoBhfWobmKs2UN1vq15GvPPC_eaIgAqBleJi_XO4nPI5i4-Gs3QlX9mV34mFlAIjAQTqZFHQ/s400/Screen%20Shot%202024-01-02%20at%2012.37.41%20pm.png"/></a></div>
<p>
When generating the display, the CRTC scans across the screen, outputting the relevant screen address for the characters
being displayed. At the end of the line a horizontal sync pulse is output, and then the same thing happens for the next
row in the same characters. Once all the rows for the characters in the first row are done, the screen address is updated
for the second row, and the next lot of characters are clocked out.
</p>
<p>
Now how do we get graphics capability without the massive increase in CPU load that comes from pixel addressable graphics?
The Exidy sorcerer (and Microbee) made use of programmable characters. Essentially a RAM was added alongside the character
ROM. The first 128 characters (standard ASCII) go to the ROM, and the upper 128 go to the RAM. Loading data in to the RAM
is a bit laborious - you need another set of address multiplexers, and another data transceiver. In the classic Microbee
there are six multiplexer chips, and two transceivers, plus the shift register for the video output.
</p>
<p>
It gets a lot more complicated in later bees. They have an extra RAM for colour for each character, plus yet another for
"attribute" which really just increases the number of characters we can have (from 256 to conceivably 64K), meaning enough
memory to have an individual bit per pixel, at the expense of more memory and more data bus transceivers.
</p>
<p>
So this is where we enter the scene. We're not interested in colour or attributes (yet), but we are interested in running Emu Joust, which required monochrome with 128 "Programmable Character Graphics" characters.
</p>
<p>
It’s possible to simplify this a bit, if you don’t mind all characters being in RAM (which means you have to pre-load them
at power up).The key to understanding how to do this is to examine the timing. In order to display 80 characters in the
standard PAL horizontal rate of 15.625 kHz, we need to use a dot clock of 13.5 MHz, which gives us a character rate (each
character being 8 pixels wide) of 1.6875 MHz (592ns). This is a long time. Even when the Bee was very first built in ’82,
you could buy 6116 static RAMs with an access time of 200ns or better. So it’s entirely reasonable to look up the screen
data, then use the result a second time to look the character data using the same physical RAM.
</p>
<p>
Our budget ends up looking something like:
<p>
<ul>
<li>9ns input mux + 200ns RAM + 22ns screen latch + 200ns RAM = 431ns.</li>
</ul>
<p>
Whereas a normal Microbee does:
</p>
<ul>
<li>9ns screen mux + 200ns screen RAM = 209ns, at the same time as</li>
<li>9ns character mux + 200ns PCG RAM = 209ns, or</li>
<li>9ns character mux + 450ns Character ROM = 459ns.</li>
</ul>
<p>
It’s pretty clear the incredibly slow 2532 is letting the show down for everyone. If we can just get rid of it, we can
make some real changes.
</p>
<p>
Let's use just one 8K RAM for everything. At the start of a character cycle the screen address is presented to the RAM
(gated using tri-state buffers). The RAM outputs the screen data. At the half-way point through the character, this data
is latched, and wrapped around back to the RAM address lines (using a second tri-state buffer) along with the row address.
The data from the RAM is now our video which may be latched into the shift register. CPU accesses to either screen or
character use a third set of tri-state buffers for the address, and a transceiver for the data.
</p>
<p>
Note that 8K is more than we ostensibly need for screen RAM (2K), Character RAM (2K), and PCG RAM (2K). Let's use the last
2K for a second "small" font, which will be useful for an 80 x 24 screen. Turns out the Motorola MCM6674 character ROM has
just the font we need, which (surprising nobody) is exactly the same as the Microbee 80 column font. To keep our Microbee
compatibility, we'll enable this little guy using the MA13 output from the 6545, so by changing screen start address from
0000h to 2000h, we select the small font.
</p>
<p>
So here's our schematics for CRT controller, video memory, and video memory access control. There's some complexity, sure,
but we can break it down a bit. The first sheet is the CRT controller, along with the video output circuitry and keyboard.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ-XUmbjmN6YhTYerfllN-hPXakFpK6dF97nodIextUSFVZ10nGmm6ve9knruvfwFyGso_QIpTsKei2QmnSlNpPc7FEKcUIj27NzlOv16URUxSEweZ-HEgBezQbRNFfz3Xsue8DW-PnyeJMGNINLwxWUMbFGI7y5t4wrTTZ_nKDPwr8LS25T0e2qoMbw/s3286/Screen%20Shot%202024-01-02%20at%201.47.58%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2286" data-original-width="3286" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ-XUmbjmN6YhTYerfllN-hPXakFpK6dF97nodIextUSFVZ10nGmm6ve9knruvfwFyGso_QIpTsKei2QmnSlNpPc7FEKcUIj27NzlOv16URUxSEweZ-HEgBezQbRNFfz3Xsue8DW-PnyeJMGNINLwxWUMbFGI7y5t4wrTTZ_nKDPwr8LS25T0e2qoMbw/s600/Screen%20Shot%202024-01-02%20at%201.47.58%20pm.png"/></a></div>
<p>
Here IC9 is our CRT Controller. It generates Video Memory addresses (MA0-10 and RA0-3) for the video memory array. The
keyboard makes use of a "light pen strobe" input on the CRTC. Some of the video memory addresses are decoded and passed
through a keyboard array. If you press a key, as the addresses scan to the key column and row, this match is passed
through to the CRTC, which dutifully latches the address and raises a status bit to tell the CPU a key has been pressed.
</p>
<p>
The DE (Display Enable), HS (Horizontal Sync), VS (Vertical Sync) and Cursor outputs from the CRTC, along with the video
bitstream from the momory page are are used to build the actual output to the CRT. HS and VS tell the CRT when to start a
new row (HS) or screen (VS). Display enable is used to gate the video output, so we don't put rubbish in the margins, and
cursor is a neat signal that can be used to invert the video for a programmable number of rows in a programmable
character position. IC16 delays the cursor and display enable signals to line up nicely with the video stream, and IC26
and 37 do the gating and cursor inversion.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1e6G4au2W64D1KFcl_JAjfUdVAaJLU5m0jjDKoAwpvmA5uhU3qCQ5hFczpyG_TPu17BnIzT5FDj7476vbXNSBzfGl1RwlUcT3DhhDF2x3x700CiU8R8Yq6MkXt6DF-6AMcjX_eiP2CxBbjg8R8y4CsqHC5Yp9b9HopiWFj078FvIjg55T9yq6IlzkjQ/s2290/Screen%20Shot%202024-01-02%20at%201.59.07%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2290" data-original-width="1576" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1e6G4au2W64D1KFcl_JAjfUdVAaJLU5m0jjDKoAwpvmA5uhU3qCQ5hFczpyG_TPu17BnIzT5FDj7476vbXNSBzfGl1RwlUcT3DhhDF2x3x700CiU8R8Yq6MkXt6DF-6AMcjX_eiP2CxBbjg8R8y4CsqHC5Yp9b9HopiWFj078FvIjg55T9yq6IlzkjQ/s600/Screen%20Shot%202024-01-02%20at%201.59.07%20pm.png"/></a></div>
<p>
Moving on to the video memory page, we have a few things to do. IC8 and 10 gate the CPU address to the video RAM (IC14)
and IC21 gates the CPU data bus. This allows us to read and write to the video memory. IC13 and 13 gates the CRTC address
to the memory for a screen access, and IC11 does similarly for the row addresses that are used during character access.
IC17 allows us to feed the results of the screen lookup back to the RAM for characters, and IC15 serialises the final
output to send to the screen. Gating for the CRTC is incredibly easy - it's just done on alternate phases of the character
clock. When CCLK is low we do screen address, and when CCLK is high we do character.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8dokqGcqsKbWQhfXtopQCEURoEQgT39XvSwPQ6MXB8AQIQ0vpNzjHSN5KilHYHUlxzMkypJB4YmDAEE4BNAxHot76DKlfdO6q_0z8xpzb3sJFmhxerN7OZX6Wa7UVMzh6Z586-g8EI1Mobo_jyuuGTLfMXTIBDHcjgsPMkr1o2rMsM9QUQHJ-Sb3acw/s2284/Screen%20Shot%202024-01-02%20at%202.07.17%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2284" data-original-width="1580" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8dokqGcqsKbWQhfXtopQCEURoEQgT39XvSwPQ6MXB8AQIQ0vpNzjHSN5KilHYHUlxzMkypJB4YmDAEE4BNAxHot76DKlfdO6q_0z8xpzb3sJFmhxerN7OZX6Wa7UVMzh6Z586-g8EI1Mobo_jyuuGTLfMXTIBDHcjgsPMkr1o2rMsM9QUQHJ-Sb3acw/s600/Screen%20Shot%202024-01-02%20at%202.07.17%20pm.png"/></a></div>
<p>
Finally we have the glue (no PLDs!) that works out what video address to generate for the various possibilities of CRTC
screen, CRTC character RAM big and little fonts), CRTC PCG, and CPU access for each of these. A couple of gates control read
and write (essentially it's all read unless the CPU wants to do a write), and the last bit delays CPU access when the CPU
tries to barge in while the CRTC is actively writing the screen, to ensure the CPU doesn't put garbage on the screen. This is
reasonably straightforward - CPU accesses are latched in IC18, causing the CPU to be put into a wait state. Once we're in
retrace, the wait is cleared and the CPU finishes doing it's thing.
</p>
<p>
As I said at the beginning, the video circuitry is most of this computer, so you'll be glad to know there's not a lot more to
describe.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjC_rdobKbacXOu3wlfISq9WBvFjc1K_SF423udCZtN-zWHYveQsGsq9mDpkeCQ87rQfJibLBWvDmMg4SKjZ0RulXq8YZaE_nY7vsvya6AWEG6rbfwYr8BU-hjaW8BAVBB_4qS0WskVx9N975LhdoEt4kT36R3bnzoyH1X6xP__XTYgU_0LN1jqkldkJA/s2282/Screen%20Shot%202024-01-02%20at%202.15.26%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2282" data-original-width="1584" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjC_rdobKbacXOu3wlfISq9WBvFjc1K_SF423udCZtN-zWHYveQsGsq9mDpkeCQ87rQfJibLBWvDmMg4SKjZ0RulXq8YZaE_nY7vsvya6AWEG6rbfwYr8BU-hjaW8BAVBB_4qS0WskVx9N975LhdoEt4kT36R3bnzoyH1X6xP__XTYgU_0LN1jqkldkJA/s600/Screen%20Shot%202024-01-02%20at%202.15.26%20pm.png"/></a></div>
<p>
Here's the CPU and memory. By using a CMOS CPU there's no need for bus transceivers and buffers everywhere (saving a
bunch of chips). The EPROM here started life as simply something to load up the fonts into video RAM on boot, but I
ended up making it big enough to include Microbee Basic as well, plus added 32K of RAM, so as one board it does everything.
</p>
<p>
The flip flop is there to enable the ROM at address 0 on reset. Once the boot sequnce is complete the ROM is able to
page itself out, presenting RAM from 0000h to 7fffh, with the upper ROM from 8000h to efffh.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5YYUMrN4lrOTxPcg3jIpFeW2T2P-odGB-uQvwpWNSQXEDBK7RpBpnSNw2oR0e4hJpCQHLQ7ceCxvJGlqbx6jRuRBbuuW6-7x5OY4PUdC2u-sfdxV39wzjLdBnqUojMabz_fHiniPq-9ox2QGm9iUGVS_5XJ6NyNfETINlctjAFjc0ZYukdaKiOgNmIA/s2286/Screen%20Shot%202024-01-02%20at%202.32.45%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2286" data-original-width="1582" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5YYUMrN4lrOTxPcg3jIpFeW2T2P-odGB-uQvwpWNSQXEDBK7RpBpnSNw2oR0e4hJpCQHLQ7ceCxvJGlqbx6jRuRBbuuW6-7x5OY4PUdC2u-sfdxV39wzjLdBnqUojMabz_fHiniPq-9ox2QGm9iUGVS_5XJ6NyNfETINlctjAFjc0ZYukdaKiOgNmIA/s600/Screen%20Shot%202024-01-02%20at%202.32.45%20pm.png"/></a></div>
<p>
Next we have some ports. A Z-80 PIO gives us some GPIO, plus bit-banged serial, a speaker, and cassette I/O. Port decoding is simply done with a 74HCT138 and 74HCT139, giving the following port map:
</p>
<ul>
<li>00 to 03: PIO</li>
<li>0B: Boot ROM and Character RAM enable port</li>
<li>0C to 0F: CRTC</li>
<li>Plus a few others that aren't used on the board but may be linked to a coreboard, if that's plugged in.</li>
</ul>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiCpWC6qhxB4p0yAwes24PbBBTiYJXyRXufZMQAKvWrZlDvYyEIHtgdW6__Yhxh9SSVvhKBz7Dgin4VUqkHqbhvQO4c2W7ZSwJcrbE-jqjzDYt4hhwU-6Y9AVuGbKsyIzH6Lj35Hb4Vpjip4KIhL-ciV98n-8SSKh3sYToMtLpbQXIuXlYSwarSSTaFA/s2280/Screen%20Shot%202024-01-02%20at%202.38.19%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="2280" data-original-width="1582" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiCpWC6qhxB4p0yAwes24PbBBTiYJXyRXufZMQAKvWrZlDvYyEIHtgdW6__Yhxh9SSVvhKBz7Dgin4VUqkHqbhvQO4c2W7ZSwJcrbE-jqjzDYt4hhwU-6Y9AVuGbKsyIzH6Lj35Hb4Vpjip4KIhL-ciV98n-8SSKh3sYToMtLpbQXIuXlYSwarSSTaFA/s600/Screen%20Shot%202024-01-02%20at%202.38.19%20pm.png"/></a></div>
<p>
Lastly we have clock and reset. The clock is derived from a 13.5MHz crystal. This provides the dot clock for the video shift register. It's divided by 4 (3.375 MHz) for the CPU clock, and by 8 (1.6875MHz) for character clock. The last eighth of each character clock is used to load the shift register, so this is derived by just anding CLK/2, CLK/4 and CLK/8.
</p>
<p>
Reset can come from two places - power up or reset switch. In each case it's just done by charging a capacitor and using a 74HC14 as a comparator.
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2g5qm2JoAW_bxdD3DP2daYb3p4r8BUlEsjBjkoSAqW9Go-UFla2eRHjQ1fa5Q035ynrltu9gNeY5FwVMNvRg6umxJO8wW5JDpXXQkEMQrdm4kL_xkVy_9AHBQd0-X_dHRfQxCEh4_j5LGZXhyphenhyphen0gAmTwjsEfR0QfImUyBH7fU54JT7k1DeXjPHvQbWVg/s2198/Screen%20Shot%202024-01-02%20at%202.56.15%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1404" data-original-width="2198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2g5qm2JoAW_bxdD3DP2daYb3p4r8BUlEsjBjkoSAqW9Go-UFla2eRHjQ1fa5Q035ynrltu9gNeY5FwVMNvRg6umxJO8wW5JDpXXQkEMQrdm4kL_xkVy_9AHBQd0-X_dHRfQxCEh4_j5LGZXhyphenhyphen0gAmTwjsEfR0QfImUyBH7fU54JT7k1DeXjPHvQbWVg/s600/Screen%20Shot%202024-01-02%20at%202.56.15%20pm.png"/></a></div>
<p>
Layout is done in KiCad. 12 thou track and space with beautiful curved traces. It really looks the part.
</p>
<p>
And after a bit of debugging, we finally have:
</p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYml6bdhJLTW6hiQJg4upDAasLB7NrFxiPZYzpMsqMaWx4eHMLtkllQh-vzFokzNDwB70G-m3WAAQIEGsHZEWXOkhOzXXQgDjX2fHgUcM_fp2wfn1yjp6HXorO_2I7gpsGF4Y0mf3DvmqVsOVjuJZcBxv-Uq8spFXUf2MM3Hr0LXjYwSpt-WJFiK8RDQ/s1280/IMG_4483.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1280" data-original-width="960" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYml6bdhJLTW6hiQJg4upDAasLB7NrFxiPZYzpMsqMaWx4eHMLtkllQh-vzFokzNDwB70G-m3WAAQIEGsHZEWXOkhOzXXQgDjX2fHgUcM_fp2wfn1yjp6HXorO_2I7gpsGF4Y0mf3DvmqVsOVjuJZcBxv-Uq8spFXUf2MM3Hr0LXjYwSpt-WJFiK8RDQ/s600/IMG_4483.jpeg"/></a></div>
<p>
As always, here's the <a href="https://drive.google.com/drive/folders/1w3KKbg7xMk5pIxgIYhvPO6PawxqKkrZ7?usp=share_link">design files</a>:
</p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-28076841554554347182023-10-06T17:44:00.007+08:002023-11-30T07:28:45.152+08:00A SuperPAK CoreboardA bit of a discussion on the Microbee forum got me thinking it'd be nice to do a simple ROM coreboard. No flash, no CF, no SD, just lots of straightforward biggish EPROMs. Then load games in, write a shell, and play.<p>
I had a look at what was available around the time the Bee was still selling, and you could get 27512 EPROMs (64K x 8 in a 28 pin package) and skinny 6264s (which the Microbee premium baseboard uses). As it happens I have a whole pile of both.<p>
So a few days work in KiCAD yeilds plunder:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZLElWVvyk0UOOJ2dlfwP0F9qL-77SitimP5QJdUFT5GoULjErOlslCNkAvZwa932nHrana5F9tux2fZLnC4d0PrzIiZMvYG5v5H4mv_nwOwqY9ADxQF2wbgs7QHjilsCCjO8GyOIv4ROBzT0PYI248_acjaAMZA_ZuD_f5bV1reOown05osFSl_zKcQ/s3450/Screen%20Shot%202023-10-08%20at%203.59.18%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1340" data-original-width="3450" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZLElWVvyk0UOOJ2dlfwP0F9qL-77SitimP5QJdUFT5GoULjErOlslCNkAvZwa932nHrana5F9tux2fZLnC4d0PrzIiZMvYG5v5H4mv_nwOwqY9ADxQF2wbgs7QHjilsCCjO8GyOIv4ROBzT0PYI248_acjaAMZA_ZuD_f5bV1reOown05osFSl_zKcQ/s600/Screen%20Shot%202023-10-08%20at%203.59.18%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaF9bffpHTn4alOzfQN_IdMm8sOtmkfIeUcxOhr04DjWXICN76so6CV-TjlX64xV7t-pNsv7fkpCWveODjMi82qLE-80WPDVHw0B5EBdNjdmQqIf-HJpOMz7n0kNGVva40B1tcck3H8c1WMgBUm53DlhR8jpCnc48cBeAU50B0S2GLhePJiZyPzPehuQ/s3068/Screen%20Shot%202023-10-08%20at%204.00.32%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1260" data-original-width="3068" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaF9bffpHTn4alOzfQN_IdMm8sOtmkfIeUcxOhr04DjWXICN76so6CV-TjlX64xV7t-pNsv7fkpCWveODjMi82qLE-80WPDVHw0B5EBdNjdmQqIf-HJpOMz7n0kNGVva40B1tcck3H8c1WMgBUm53DlhR8jpCnc48cBeAU50B0S2GLhePJiZyPzPehuQ/s600/Screen%20Shot%202023-10-08%20at%204.00.32%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7a5q2Ogj5lScxOX_l5WLjlqgNkk9Tg6C_BDEpTAaSoAMJRmT0JF7BXiaGdKBDWHcPKCbgUbQG18ubX6-shiJsP5XoibmE7IIe64IzQa-FnvjISNJ00CADWc4jktYTXe-db6qzfH0UOk7oXCfM8F4AumlhqVJDoWiGSC0x3gBhuEFO9VsWMsUJZAoS7A/s3056/Screen%20Shot%202023-10-08%20at%204.00.45%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1256" data-original-width="3056" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7a5q2Ogj5lScxOX_l5WLjlqgNkk9Tg6C_BDEpTAaSoAMJRmT0JF7BXiaGdKBDWHcPKCbgUbQG18ubX6-shiJsP5XoibmE7IIe64IzQa-FnvjISNJ00CADWc4jktYTXe-db6qzfH0UOk7oXCfM8F4AumlhqVJDoWiGSC0x3gBhuEFO9VsWMsUJZAoS7A/s600/Screen%20Shot%202023-10-08%20at%204.00.45%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeRcVntVJO6aDEKV0EqOIXqCj90q_aIVZX28THdrZTewYkJeLH2WuEhm1AxbnSMYsOcLQNtcAIrksBEWc7wZoWcbG-eUaYKvUh3mmCSNTWj7VT4k39c4443HNyq4P_NEodZwlvRzqhoohJzGOUBHV5NZ7RHy-1-65zttrSU_lfpz-OfG-GFNRJOXTegQ/s3424/Screen%20Shot%202023-10-08%20at%204.01.43%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2392" data-original-width="3424" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeRcVntVJO6aDEKV0EqOIXqCj90q_aIVZX28THdrZTewYkJeLH2WuEhm1AxbnSMYsOcLQNtcAIrksBEWc7wZoWcbG-eUaYKvUh3mmCSNTWj7VT4k39c4443HNyq4P_NEodZwlvRzqhoohJzGOUBHV5NZ7RHy-1-65zttrSU_lfpz-OfG-GFNRJOXTegQ/s600/Screen%20Shot%202023-10-08%20at%204.01.43%20pm.png"/></a></div>
One has to be considered in using round the tracks in KiCAD. Each time you run it it seems to take about twice as long as the last time, so if you do it too much the board becomes impossible to edit.<p>
Edit: Yay, boards have arrived!<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDSAFaiAt6BKOxVHlGkvQeYr0ZSxEhlZ6l-CkKa8erZoac9z1phWOu7sNV3YgTSU6iHPI3uEFieDY1cSXl90vGI1DpvWQ_mI2PnDPbJwm5V7fUsu_KOwe5z26cWNJtnFW0gZKAfuZQIDv92uHQoT2_9VQ_Hr35WlJ5sr_-8FMIYbux99jD3RmzGxXChg/s4032/IMG_2887.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="3024" data-original-width="4032" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhDSAFaiAt6BKOxVHlGkvQeYr0ZSxEhlZ6l-CkKa8erZoac9z1phWOu7sNV3YgTSU6iHPI3uEFieDY1cSXl90vGI1DpvWQ_mI2PnDPbJwm5V7fUsu_KOwe5z26cWNJtnFW0gZKAfuZQIDv92uHQoT2_9VQ_Hr35WlJ5sr_-8FMIYbux99jD3RmzGxXChg/s600/IMG_2887.jpeg"/></a></div>
And assembled using parts I had to hand. Note no battery backup as yet, plus I didn't have a 74C or 74HC14, so have substituted a 74HC04 (not schmidt trigger). As a result reset is really hit and miss.<p>
In amy case, it boots, both on non-premium and premium baseboards, and I can run Emu Joust and access PAK. I shall order the remaining parts through the week.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrKWw66g1FFhMv-7Ifvk3fbY9Xgz5xS-nNEZDl2bUfp_EXaLPFPQ_WraHUDTXrsVuWIVdn3GvxSC0pNQ8YgSWrovqp8VVKp7qDwdmW8oOYIeSGxq3IKJZhaxZi95hY_S65Axaq0cw_h6OWqqO_CbMkMts3oIvIRYhIBWy37uvkhyphenhyphenU6WA7zIu5WkQvEZA/s1280/IMG_4423.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="400" data-original-height="1280" data-original-width="960" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrKWw66g1FFhMv-7Ifvk3fbY9Xgz5xS-nNEZDl2bUfp_EXaLPFPQ_WraHUDTXrsVuWIVdn3GvxSC0pNQ8YgSWrovqp8VVKp7qDwdmW8oOYIeSGxq3IKJZhaxZi95hY_S65Axaq0cw_h6OWqqO_CbMkMts3oIvIRYhIBWy37uvkhyphenhyphenU6WA7zIu5WkQvEZA/s400/IMG_4423.jpeg"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9uiPA-ihKucxAikllPngdY-kOxeROPPxTQAgNj4g5BED3bESSHMj3HAB6lk6K0y0nMecIK316lALzn-4We_b9xCPREIEZoAfe2z-CfgMZgdS3VJnZyCzL9sdS2hCeY8p7Cpt4IcWnTNDqDxJ6Cv31C-rv-KPjOBWLdb-ZFCW6Od7esvimhYVzaZ2iIg/s1280/IMG_4424.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="400" data-original-height="1280" data-original-width="960" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9uiPA-ihKucxAikllPngdY-kOxeROPPxTQAgNj4g5BED3bESSHMj3HAB6lk6K0y0nMecIK316lALzn-4We_b9xCPREIEZoAfe2z-CfgMZgdS3VJnZyCzL9sdS2hCeY8p7Cpt4IcWnTNDqDxJ6Cv31C-rv-KPjOBWLdb-ZFCW6Od7esvimhYVzaZ2iIg/s400/IMG_4424.jpeg"/></a></div>
An adaptor board to simplify software development - this allows us to plug a single 32 pin EEPROM in in place of four 28 pin EPROMS, and can be assembled with a zif socket.
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_C7ZNzHRFEEXogRMxetLkFSHtWWXgKk2m_5IQPr9egyUnp2gf9nYdAKtT8rQDxjMJ8fWRqTtprSemtVp7iSS4YoOqmg8vMkH9IrvdhmcAQm4rwts_7mW2N4YCgxLMBLNSYM9CwLsD_ZVlDFepNPJHGBPY498T4rHmdGG6_-QSuQbDtRy0TM1k1ncpdA/s2250/Screen%20Shot%202023-11-08%20at%207.43.32%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1270" data-original-width="2250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_C7ZNzHRFEEXogRMxetLkFSHtWWXgKk2m_5IQPr9egyUnp2gf9nYdAKtT8rQDxjMJ8fWRqTtprSemtVp7iSS4YoOqmg8vMkH9IrvdhmcAQm4rwts_7mW2N4YCgxLMBLNSYM9CwLsD_ZVlDFepNPJHGBPY498T4rHmdGG6_-QSuQbDtRy0TM1k1ncpdA/s600/Screen%20Shot%202023-11-08%20at%207.43.32%20am.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidoq9K06cMpwdRTQaUcsYWCW6ftvTjJdOzOofbX6J0wLxz9gXH0RSJFUrp9HOAsM-Glh57KaZtgFA58NRqJV9j89GhGAJjYUzAMzbdrxhZDnf873Eobc0MG-zOUr_ouSkT0aowGWG9jaYBso0HZcTVYawJr_ayl0QtpetHDflvAowHyIWcfE4DrbxDFA/s1722/Screen%20Shot%202023-11-08%20at%207.42.58%20am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" height="600" data-original-height="1722" data-original-width="1120" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidoq9K06cMpwdRTQaUcsYWCW6ftvTjJdOzOofbX6J0wLxz9gXH0RSJFUrp9HOAsM-Glh57KaZtgFA58NRqJV9j89GhGAJjYUzAMzbdrxhZDnf873Eobc0MG-zOUr_ouSkT0aowGWG9jaYBso0HZcTVYawJr_ayl0QtpetHDflvAowHyIWcfE4DrbxDFA/s600/Screen%20Shot%202023-11-08%20at%207.42.58%20am.png"/></a></div>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYY9y4zBTcHn1_GD35BBnZVc8lqVg5Sv5sVL32xEMp7YPE5DU7DiQzv8AJ1aLCNL0PZxIq7Z3Kf0wFuj5dfUqd8J6UOT-jftYLvpgGF431HEOZXcyirrkfnhcj4CD1zdae7hQdjBmqVvEXA5JCTxxWmbRwQoqV_5av21Jvr5PwnbP2lH1S9cgHM9q5UA/s1280/IMG_4473.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYY9y4zBTcHn1_GD35BBnZVc8lqVg5Sv5sVL32xEMp7YPE5DU7DiQzv8AJ1aLCNL0PZxIq7Z3Kf0wFuj5dfUqd8J6UOT-jftYLvpgGF431HEOZXcyirrkfnhcj4CD1zdae7hQdjBmqVvEXA5JCTxxWmbRwQoqV_5av21Jvr5PwnbP2lH1S9cgHM9q5UA/s600/IMG_4473.jpeg"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-46783728296669368202021-04-30T11:19:00.006+08:002023-10-18T20:28:25.534+08:00Further work on a Microbee 1248-6 mainboardThis is the definition of a long-term project. I have a bare Microbee 1248-6 mainboard. It's one of the later revisions of this board. Being blank, it's a good candidate for replication.<p>
Some years ago I created a schematic for it in Protel, and made a PCB. The PCB wasn't particularly accurate, as I mainly just threw the autorouter at it. So (probably) functional, but not particularly exciting.<p>
Success at getting KiCad to do beautiful curved traces reignited the spark of that particular project, so I pulled out the files and had another look.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYmftQadsfkau3sV-taLle6ROHIZPf9aBpbkbpRlJh52Asz2CXmDDFS0gJsBoBmN819KrR7xIGyWwYydBiMbIIPo2Qd7zZU_2zx346VF248emy6mqbaf7_SNchlfKA9HmSJL5WzVhtxKY/s2048/Screen+Shot+2021-04-30+at+11.07.58+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1598" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYmftQadsfkau3sV-taLle6ROHIZPf9aBpbkbpRlJh52Asz2CXmDDFS0gJsBoBmN819KrR7xIGyWwYydBiMbIIPo2Qd7zZU_2zx346VF248emy6mqbaf7_SNchlfKA9HmSJL5WzVhtxKY/s600/Screen+Shot+2021-04-30+at+11.07.58+am.png"/></a></div>
I imaged the board at 600dpi using a scanner. Then cropped a section of that and fed it into the gimp. I played around with levels to increase the contrast between tracks and boards.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR24lTWFo6xKfzw2dhwoaES0R4dSw3Hc2yw471K1JNXODdokf69h-YmgC_bjKTx16BzSQmPmBtoINK0Yfk1BQIv-VSVnVec76Yj3klh5TKuCTGTXvW4iYaOExMlDPSiedQobPc5q9Xw1I/s2048/test.jpg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1727" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR24lTWFo6xKfzw2dhwoaES0R4dSw3Hc2yw471K1JNXODdokf69h-YmgC_bjKTx16BzSQmPmBtoINK0Yfk1BQIv-VSVnVec76Yj3klh5TKuCTGTXvW4iYaOExMlDPSiedQobPc5q9Xw1I/s600/test.jpg"/></a></div>
Then I put the result of that into the KiCad bmp to component converter. This tool is designed for making fancy logos, and converts a bitmap image into a bunch of vectors that can be used for gerber plotting. The file goes on the silkscreens. I have seen a board made by one of the guys at the microbee software preervation project that used this technique to create gerbers directly, but there were issues with getting board houses to accept this.<p>
So now the next step. Trace over the image in KiCad using proper components, tracks (15 mil) and vias. It takes a while, but it's enjoyable bead therapy work. There's no need to accurately follow the original. Indeed around corners it's better to leave the round the corners plug in to do it neatly.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIrNtvaTjS_AzmiQpNs9YUeFoNvmR-1zlXsBnH2LMgkuaEOwrczy2IMxry2zgKOx1l7C-G8ED03ZMPLHy8EC_6cclN3mNxsKSeGjfJDGwtJDoujW-AtZ84fKiT6AjAxZzoUzUKVhKQJU8/s2048/Screen+Shot+2021-04-30+at+11.12.04+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1222" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIrNtvaTjS_AzmiQpNs9YUeFoNvmR-1zlXsBnH2LMgkuaEOwrczy2IMxry2zgKOx1l7C-G8ED03ZMPLHy8EC_6cclN3mNxsKSeGjfJDGwtJDoujW-AtZ84fKiT6AjAxZzoUzUKVhKQJU8/s600/Screen+Shot+2021-04-30+at+11.12.04+am.png"/></a></div>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUvnB0TpK1KA9sOGg4nn3OY98Wkutly245A3_lHB_3tnUNUa2UcV29TtMX_tfODG5wca-NYwMVb0gau-Tsi5tO1VMN9q8Y4_-do76Q7exT9h4xyWsWEx655S3TkignS60nVmApa2r1sx4/s2048/Screen+Shot+2021-04-30+at+11.11.42+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1223" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUvnB0TpK1KA9sOGg4nn3OY98Wkutly245A3_lHB_3tnUNUa2UcV29TtMX_tfODG5wca-NYwMVb0gau-Tsi5tO1VMN9q8Y4_-do76Q7exT9h4xyWsWEx655S3TkignS60nVmApa2r1sx4/s600/Screen+Shot+2021-04-30+at+11.11.42+am.png"/></a></div>
For the bottom layer, just process the scan the same way, then convert it to a silkscreen component, and flip it when you place it.<p>
This makes a real board, that can be DRC checked against a netlist (when I get around to putting the schematic into KiCad), to ensure that it's correct. Finally, run the board through the round the tracks plugin to smooth things out and create absolutely stunning artwork, even better than that used to make these computers in the first place.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3-MwnhANSbHACj5hMaCva82QUw2mnBL4X5LfnSmclIhncaqItXK_GeJMYg3aQfmRytXpHK0v02JqBlDueJiYVLWnE2CIlvxkeBvwxmhw45oPFpbvYkBcQzKpvYNcPXT_70_xJUvn4ftM/s2048/Screen+Shot+2021-04-30+at+10.51.50+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1451" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3-MwnhANSbHACj5hMaCva82QUw2mnBL4X5LfnSmclIhncaqItXK_GeJMYg3aQfmRytXpHK0v02JqBlDueJiYVLWnE2CIlvxkeBvwxmhw45oPFpbvYkBcQzKpvYNcPXT_70_xJUvn4ftM/s600/Screen+Shot+2021-04-30+at+10.51.50+am.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisyXonDVv0j6NdXYf_SO-klJrc5b1NHqyKhn4OIxSlK0FF8zNQuFhEH5B_lCCShJPsCF_LolgVTaxqoLZRyLXbNIcBqDqwTpiFLP6NhyJXgBH-0qXO9Din2Oyl1nk0c_F890Q29PWQCxM/s2048/Screen+Shot+2021-04-30+at+10.53.08+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1461" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisyXonDVv0j6NdXYf_SO-klJrc5b1NHqyKhn4OIxSlK0FF8zNQuFhEH5B_lCCShJPsCF_LolgVTaxqoLZRyLXbNIcBqDqwTpiFLP6NhyJXgBH-0qXO9Din2Oyl1nk0c_F890Q29PWQCxM/s600/Screen+Shot+2021-04-30+at+10.53.08+am.png"/></a></div>
Edit: After a few days work, it's looking pretty cool:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3Z1-aT8IsWOA1qKl8mbbpLN7vjii7xobKsXofv0p5hitb9W4W7QUzvn_STA3PfTuhgfuIGLaPIkciIuppadlw8BSQEGC9Xq-LDmigCoTg43H9KVyOdpgZ8RIrCPYwY_aAYXWmN-_pSGk/s2048/Screen+Shot+2021-05-05+at+6.58.01+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1449" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3Z1-aT8IsWOA1qKl8mbbpLN7vjii7xobKsXofv0p5hitb9W4W7QUzvn_STA3PfTuhgfuIGLaPIkciIuppadlw8BSQEGC9Xq-LDmigCoTg43H9KVyOdpgZ8RIrCPYwY_aAYXWmN-_pSGk/s600/Screen+Shot+2021-05-05+at+6.58.01+am.png"/></a></div>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp_7OioNViVOHhYYLeiu-Tj1VIdflUfZkVhUR_LcIgYTnUoazzlMlQ0EBCp-Q1i1_qDFg3pUb5uCszipGuM4iMTqD-16BUgKlOzsEY-B1bta8MpuaHRBShjxVH-EqQXstYMSKvm_M3tWY/s2048/Screen+Shot+2021-05-05+at+6.59.01+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1443" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp_7OioNViVOHhYYLeiu-Tj1VIdflUfZkVhUR_LcIgYTnUoazzlMlQ0EBCp-Q1i1_qDFg3pUb5uCszipGuM4iMTqD-16BUgKlOzsEY-B1bta8MpuaHRBShjxVH-EqQXstYMSKvm_M3tWY/s600/Screen+Shot+2021-05-05+at+6.59.01+am.png"/></a></div>
And with the soldermask obscuring all the pretty curvy traces:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgl_rOG5F2YZk56CQrEEe_3I9VVHohHYkYahT6xxu_xLnI9YapUWcmRMmf-QkNoFgQ7x8fqsE1qVMUmvKQ8w4YgcBKEo7MFHUpJNraxGPXnTAJZeXOLNcCE68r8FOTSUriXIkmBo4xxtHM/s2048/Screen+Shot+2021-05-06+at+2.19.07+pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1212" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgl_rOG5F2YZk56CQrEEe_3I9VVHohHYkYahT6xxu_xLnI9YapUWcmRMmf-QkNoFgQ7x8fqsE1qVMUmvKQ8w4YgcBKEo7MFHUpJNraxGPXnTAJZeXOLNcCE68r8FOTSUriXIkmBo4xxtHM/s600/Screen+Shot+2021-05-06+at+2.19.07+pm.png"/></a></div>
Finally, I did the schematic entry in KiCAD. This meant that the PCB now had net information, which then allowed me to do a meaningful DRC. There were _a lot_ of problems. Firstly, the original board has some unused gates, with floating (=oscillating if CMOS logic is used) inputs. There was also duplicated designators on the board (C33), some bits just not connected per the schematic - notably some of the clamp diodes around the serial port don't actually clamp, plus the emitter of TR4 is not connected to anything on the PCB.<p>
Anyway, I fixed the obvious things, and mainly made the schematic agree with the PCB where it didn't matter (swapped designators, swapped pins).<p>
So here's the final glorious thing, in a form that I can get one made. 15 thou tracks and 9 thou spaces (I know, very assymetrical). Totally ready to build.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDEIL7APog_CUlucM7EmCbykTKOQVyUlfHwwIkktpY4ySagvjyCvJjYlkoyVlTECDDiiivSykLI_-zOWgCpGSxLyD7fNQd0W-55LH9cEsF2y70oDCSii4JXGBFeSzoiWILS35oS4LoKz0QsmdSgj_BL-5ipNEArStG8rvj9rBGuIOWSxgICuF_WB4riA/s3194/Screen%20Shot%202023-10-16%20at%205.18.22%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2254" data-original-width="3194" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDEIL7APog_CUlucM7EmCbykTKOQVyUlfHwwIkktpY4ySagvjyCvJjYlkoyVlTECDDiiivSykLI_-zOWgCpGSxLyD7fNQd0W-55LH9cEsF2y70oDCSii4JXGBFeSzoiWILS35oS4LoKz0QsmdSgj_BL-5ipNEArStG8rvj9rBGuIOWSxgICuF_WB4riA/s600/Screen%20Shot%202023-10-16%20at%205.18.22%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiv0mMeQOsxtuLmwUB3jJ3OihppJCf1tEIE8LOjl9dWFWvJ6NtYqfimb4yRib_b0u0KRO9ZMuwiAtpULUSrWTt64cjObEB16hwZ6MQVTN6MLPWjuKCk6nsQ81YQTPVokjXnIJveDrLeGXa1yAbUJrVpANUbQwTObbVNGErO8RMC-Pkrt_jJOWCtZc_DbA/s3176/Screen%20Shot%202023-10-16%20at%205.18.36%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2240" data-original-width="3176" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiv0mMeQOsxtuLmwUB3jJ3OihppJCf1tEIE8LOjl9dWFWvJ6NtYqfimb4yRib_b0u0KRO9ZMuwiAtpULUSrWTt64cjObEB16hwZ6MQVTN6MLPWjuKCk6nsQ81YQTPVokjXnIJveDrLeGXa1yAbUJrVpANUbQwTObbVNGErO8RMC-Pkrt_jJOWCtZc_DbA/s600/Screen%20Shot%202023-10-16%20at%205.18.36%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjb2gofUnfRVYAL72vyjFtrIhEtTQdY8KS1qfwmiCfh82GcMPYl9PSw-66tYcsJLznHn14DFBPxylRl2lA6ZmR99i4L8oSFErX0CyBfsGh16Kaw-VP0DlZjdVtgXiMe94hwNErWzWB0Ikci_7_FTsHjPEE6UEQDqv7BcDgxY2Ylf9LQHBe-GsI49EZMwQ/s3092/Screen%20Shot%202023-10-16%20at%205.20.45%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2138" data-original-width="3092" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjb2gofUnfRVYAL72vyjFtrIhEtTQdY8KS1qfwmiCfh82GcMPYl9PSw-66tYcsJLznHn14DFBPxylRl2lA6ZmR99i4L8oSFErX0CyBfsGh16Kaw-VP0DlZjdVtgXiMe94hwNErWzWB0Ikci_7_FTsHjPEE6UEQDqv7BcDgxY2Ylf9LQHBe-GsI49EZMwQ/s600/Screen%20Shot%202023-10-16%20at%205.20.45%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimzpY7KQcwcYslYJOrp199EbF9x5iJxlVgos3iZMTBJAXFleuXT4sNmGmjjKZGbRQV-4drQouWJ0X9PALjZdGdYpq2PGwDdO4vo6Hd3W1w14WXrMqQOyfvc9LJy_xxAnWwgBEBxkCmIIVua8JPy8loadHT3RHwNuA-NnjtV6RaqfqcF-oeNvKXCTCFKQ/s3362/Screen%20Shot%202023-10-16%20at%205.21.08%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2352" data-original-width="3362" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimzpY7KQcwcYslYJOrp199EbF9x5iJxlVgos3iZMTBJAXFleuXT4sNmGmjjKZGbRQV-4drQouWJ0X9PALjZdGdYpq2PGwDdO4vo6Hd3W1w14WXrMqQOyfvc9LJy_xxAnWwgBEBxkCmIIVua8JPy8loadHT3RHwNuA-NnjtV6RaqfqcF-oeNvKXCTCFKQ/s600/Screen%20Shot%202023-10-16%20at%205.21.08%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8FTfgV3ADP41iHgbchGlflhc7vcMTIbzThZtBecpx3J0q_iud5jvQqzHGyGG9bocWwLMVhm0LkEwK7zJd0bufgJzW_OXEdd_ugaKB65xTmPesqEHATh9fvJrx_-fuMt01d0DL_pfM7zW0NBKa2XeJKULKF6rr7mpfmht8h56AVNvkFowDc6hKqQVSZg/s3426/Screen%20Shot%202023-10-16%20at%205.21.38%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="2400" data-original-width="3426" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8FTfgV3ADP41iHgbchGlflhc7vcMTIbzThZtBecpx3J0q_iud5jvQqzHGyGG9bocWwLMVhm0LkEwK7zJd0bufgJzW_OXEdd_ugaKB65xTmPesqEHATh9fvJrx_-fuMt01d0DL_pfM7zW0NBKa2XeJKULKF6rr7mpfmht8h56AVNvkFowDc6hKqQVSZg/s600/Screen%20Shot%202023-10-16%20at%205.21.38%20pm.png"/></a></div>
Of course now it's digitised, it's trivial to change. Like for example replacing all the keyswitches with easy to buy Cherry ones, plus replacing the unobtanium IC16 82S123 PROM with an easily available GAL16V8...<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj41sjFQkwZUjugwuI4OpbRNF9iynukmkFzCXzz1dZMHpV5axuvWd8oYEnt6HgPWVkXXNqFVssX-BnabW8BImOoMetTaBFOqlrYVAyeia7uGD65QA7iC-aTiLJXyPRD8T97GtHHoXXbWYCPqvEUy1Dwleo0BKx5JeksLXIMrsYVWOhhL-O4PHkrnXh7zg/s2538/Screen%20Shot%202023-10-18%20at%208.24.25%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1792" data-original-width="2538" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj41sjFQkwZUjugwuI4OpbRNF9iynukmkFzCXzz1dZMHpV5axuvWd8oYEnt6HgPWVkXXNqFVssX-BnabW8BImOoMetTaBFOqlrYVAyeia7uGD65QA7iC-aTiLJXyPRD8T97GtHHoXXbWYCPqvEUy1Dwleo0BKx5JeksLXIMrsYVWOhhL-O4PHkrnXh7zg/s600/Screen%20Shot%202023-10-18%20at%208.24.25%20pm.png"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinQS08jkjgEQZih6wJC958q8BGOqIhx-UQAnplgmAEHLw8h2rqgePP09QvwR7JdCYlVoNidNx49I9O2FMIkYAt6YgSy6WJAPOc1CVmlSg3WWLkK2JIKoMBuBa73I40LPl-uNFaUI2atlwKrCCAGkMnnZyOWCUk9C3yI-9BEO02lZ4hLPAsVmUNz-wfbA/s2528/Screen%20Shot%202023-10-18%20at%208.25.14%20pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1786" data-original-width="2528" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEinQS08jkjgEQZih6wJC958q8BGOqIhx-UQAnplgmAEHLw8h2rqgePP09QvwR7JdCYlVoNidNx49I9O2FMIkYAt6YgSy6WJAPOc1CVmlSg3WWLkK2JIKoMBuBa73I40LPl-uNFaUI2atlwKrCCAGkMnnZyOWCUk9C3yI-9BEO02lZ4hLPAsVmUNz-wfbA/s600/Screen%20Shot%202023-10-18%20at%208.25.14%20pm.png"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com1tag:blogger.com,1999:blog-924768814112596827.post-11526532431682005462021-04-24T22:10:00.003+08:002021-04-26T09:59:11.802+08:00Microbee SuperPAK - An EPROM Expansion BoardQuite a while ago I developed hardware for a compact flash coreboard for my Microbee. This added IDE based compact flash storage, allowing massive disk storage under CP/M. Others helped out with the BIOS software. It never got to the point where I was completely happy with it. Compact Flash cards are finicky things, and the combination of a 5V system and very slow timing conspired to make things less than 100% reliable. Being a read/write thing, every time something crashed it would corrupt the directory structure and necessitate reformatting the card. This was (and is) frustrating.<p>
I realised that the reason I wanted all the storage was just so I could have a straightforward way of loading software on the Bee that doesn't necessitate waiting for tapes to load. I've got a couple of dozen games and suchforth that I like to play every now and again, and frustrations in getting it going mean I don't play with the gear as much as I'd like.<p>
So back in the day I had a "ROMPAK" for my bee, which was a little expansion board that could take eight 2764 EPROMS, for a whopping 64K of storage. By writing to port 0A, you could select one of the eight ROMs, and it'd appear at C000 in the memory map. We used it to allow us to have Wordbee, EDASM and the Mytek wordprocessor in the same bee without having to swap ROMs, and it was neat. I envisaged loading Emu Joust into a couple of EPROMs and writing a short routine to copy it into RAM at the corect location and then jump to it.<p>
So this board allows you to do that, plus maybe store some other games and bits of software. I've allowed all 256 possible PAK ROM positions, using an 8-bit latch and four 27C040 EPROMs. These are current production parts that go for the princely sum of $8 or so ea, as long as you don't mind them in a OTP flavour. You can get Flash versions too.<p>
The idea is that the first PAK location holds software with a menu, that allows you to choose what you want to run, then copy that into RAM (or leave it bee in EPROM if it's a PAK thing), and execute it. Sort of like the PC85 but on steroids. The software to do that should be a doddle, or at least much easier than writing stuff to run CP/M. Even better, there's no FPGAs and no CPLDs to worry about. all the decode is done with bog-basic 74 series parts.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5vAI5Ze_XUDHaN0KpFKUzFxi78gdu0RHGJngpJAzJ_f5g0F8t5BEsRqspcQ6l0IVpIiuIWFWchK9S7waVj4TJZ0d2uWPgL_5YRTB2GoPnyqJdR_awROpVz8IGV5fLWlz10DfLn6CKERU/s1054/Screen+Shot+2021-04-24+at+9.50.27+pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="722" data-original-width="1054" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5vAI5Ze_XUDHaN0KpFKUzFxi78gdu0RHGJngpJAzJ_f5g0F8t5BEsRqspcQ6l0IVpIiuIWFWchK9S7waVj4TJZ0d2uWPgL_5YRTB2GoPnyqJdR_awROpVz8IGV5fLWlz10DfLn6CKERU/s600/Screen+Shot+2021-04-24+at+9.50.27+pm.png"/></a></div>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqc29zohevTChul2M5dCTxs6C9izzN4aSqN28PX7oMXZ4SnL-k5RzIZCIVJc3abiEY7lSgWOR675MIH5dRp60Wsdh2WvJGFSvULCZRsS9Bgq87x_RrDwwyxjT0Wg7uDf-sjUfu3fLzTL0/s2048/Screen+Shot+2021-04-24+at+10.09.13+pm.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1423" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqc29zohevTChul2M5dCTxs6C9izzN4aSqN28PX7oMXZ4SnL-k5RzIZCIVJc3abiEY7lSgWOR675MIH5dRp60Wsdh2WvJGFSvULCZRsS9Bgq87x_RrDwwyxjT0Wg7uDf-sjUfu3fLzTL0/s600/Screen+Shot+2021-04-24+at+10.09.13+pm.png"/></a></div>
Edit: I just found the "round the corners" and "teardrop" plugins for KiCad, which make boards look like they were layed out using bishop graphics and tape. I reckon it looks so nice that it's worth leaving the solder mask off and going for an ENIG finish, ala expensive Hewlett Packard boards of the 1980s.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAfhVHFHlRK1oxBesvUtB0WtSdnA0rNxhCv7YnUuxHSs9rA4N8DIK77rzO-456TuiKQYxvXsjpgAUmM_NvLgtPFWVebEJkpc3ZZG9YT6dMqiFWnw4erJ9wksFpDAYRDRpvydYgLPmuso4/s2048/Screen+Shot+2021-04-26+at+9.54.06+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1367" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAfhVHFHlRK1oxBesvUtB0WtSdnA0rNxhCv7YnUuxHSs9rA4N8DIK77rzO-456TuiKQYxvXsjpgAUmM_NvLgtPFWVebEJkpc3ZZG9YT6dMqiFWnw4erJ9wksFpDAYRDRpvydYgLPmuso4/s600/Screen+Shot+2021-04-26+at+9.54.06+am.png"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-25717314557974149082021-01-17T07:31:00.007+08:002021-01-17T09:06:01.952+08:00Suzy's Super Rosin Paste Flux.<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKAQBWE0D5URW_qW6pA_JaOP21etmez1Lv9MKCq1tg_CNnaqOrgbbSSL67ZW5oZgbC7f0liFHDROeN938BEX_X9i5-JVcmeq2VGMf5lQhxBcr9MfMSg2dPMHZG7guzijajxoyfVpNB2Sg/s1280/IMG_1520.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="648"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKAQBWE0D5URW_qW6pA_JaOP21etmez1Lv9MKCq1tg_CNnaqOrgbbSSL67ZW5oZgbC7f0liFHDROeN938BEX_X9i5-JVcmeq2VGMf5lQhxBcr9MfMSg2dPMHZG7guzijajxoyfVpNB2Sg/s600/IMG_1520.jpeg"
/></a>
</div>
<p>
We're in a no-clean, water-based, lead-free world, and that sucks. Electronics
manufacturing is about getting product out the door with as little effort as
possible, so they leave the flux on the board rather than clean it off. This
"no-clean" flux isn't just a pretty pathetic flux, it's also a right pain to
clean off the board afterwards, so it should really be called "can't-clean".
All well and good if your standards are low, but if you care about the quality
of what you make, you'll want real rosin flux.
</p>
<p>
Decent rosin paste flux is getting harder to find every time I go looking, and
with the secrecy around formulations who knows what's in that stuff. The
solution is to take control of the process and make our own. Before I start
though here's a quick primer on what flux is, and what the various
formulations for electronics work are. You have to really understand your
needs to formulate a flux that's appropriate.
</p>
<p>
Flux is used to exclude air from the join while you're heating it, in order to
prevent the corrosion of metals that happens when you heat them up. It also
contains varying amounts and strengths of acids, which bind to the oxides
present on the surface of the metal and remove them from the join, so that
when you stick solder in it's able to wet the parent metal properly. You want
it in either a liquid form or a paste form. Liquid flux allows you to paint it
on with a brush (thick liquid) or dispense it with a pen (runny liquid) or
spraycan (very runny liquid). For board assembly I like to dispense with a
syringe. This allows me to use very thick paste flux that stays in place on
the board. I like it to be a little tacky, so when I place surface mount
components, they don't roll around. The solvents used between liquid and paste
fluxes are different, but the key ingredient is still the rosin.
</p>
<p>
The various types of flux are:
</p>
<ul>
<li>
Rosin Flux. This is the grand-daddy of fluxes. It's made from tree sap,
that's had the volatiles (turpentine) boiled off. The resulting rosin is an
amber crystaline solid, that breaks fairly easily. It's mildly acidic, due
to the presence of abietic acid. Being a solid it needs some sort of solvent
to make it useable to coat the joint with. It's mild, and perfect for board
assembly where you're using good quality, reasonably fresh components. When
you solder the join, most of the solvent boils off, leaving the glassy rosin
behind. This is reasonably easy to remove using more solvent.
</li>
<li>
RA flux. Rosin Activated. This is rosin with various acids added to attack
the oxides on your circuit board and component leads. It's a bit on the
nasty side for most board assembly work, as we're usually working with
boards and components that have been processed well (HASL or ENIG coating
etc) and stored well to exclude oxides. This is used for those awful
terminals that have been out in the air or on the boat for decades. It is
imperative that you clean it off after soldering, as the acids will continue
eating the metal and after a few years it'll stop working. The residue
that's left after soldering is dark in colour, containing the oxides that
have bound with the acid in the flux. It's harder to remove than the oxides
from rosin flux, but still doable with a solvent and a bit of scrubbing.
</li>
<li>
RMA flux. Rosin Mildly Activated. Reduce the amount of acid in RA flux and
you get RMA flux. It's a compromise. Good as a substitute for rosin when
things aren't wetting well (old components, old boards). You need to clean
it off afterwards, as it'll eventually damage the equipment otherwise.
Cleaning wise, it's a mid-step between rosin and RA.
</li>
<li>
No-clean flux. This is a formulation made from random industrial chemicals,
gelling agents, what-have you, that's supposed to mimic real flux then dry
clear so the person contracting you for assembly work doesn't notice that
you haven't cleaned the boards. It's motive is to skip a step, not to
improve the product. Much worse though, it's often incredibly hard to clean
off. The manufacturers want something that doesn't get tacky or runny in
use, so they make it so that it dries hard. This equals very difficult ro
remove. Don't use it. Your boards deserve better.
</li>
</ul>
<p>
Here's a recipe for real rosin paste flux just like your grandma made when you
were a kid, back when she worked as an industrial chemist. Nothing but the
finest free-range organic ingredients, and made with love. Cook some up and
gift it to that special engineer in your life, or just make a batch for your
own use.
</p>
<p>
Seriously, this doesn't just resemble commercial rosin paste flux. It's the
actual thing. It's not activated, which means that there are no acids added
besides the naturally occurring abietic acid in the rosin. You can add
additional acids if that suits your process, but I'm not particularly
interested in that. Ninety percent of the time I'm happy with straight rosin,
so I can use the commercial stuff for that occasional stubborn join.
</p>
<p>
This recipe makes enough to last a typical engineer a good few months. The
ratio of rosin to vaseline yields a flux that's just right for syringe
dispensing, with good tack.
</p>
<p><b>Ingredients:</b></p>
<ul>
<li>15g of gum rosin, in chunks.</li>
<li>10g vaseline.</li>
<li>Isopropyl alcohol (varies from 0g to 5g).</li>
</ul>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIJ017pRSqZw4_KjjkQzpyqQAQZy8zPLOQ-CLdpjn3qvUHfNsyVaJ4x7hr7aM8z-NAsQ5WwwTZaOqu-EHI_VO5i-DmOIAntoGJdA8d7vOyT7xIJiCYz-DTmUmJKJ5RZSHaHtj8PjWpROA/s1280/IMG_1519.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="960"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIJ017pRSqZw4_KjjkQzpyqQAQZy8zPLOQ-CLdpjn3qvUHfNsyVaJ4x7hr7aM8z-NAsQ5WwwTZaOqu-EHI_VO5i-DmOIAntoGJdA8d7vOyT7xIJiCYz-DTmUmJKJ5RZSHaHtj8PjWpROA/s600/IMG_1519.jpeg"
/></a>
</div>
<p>
I just buy rosin online. It's got a huge pile of uses, both industrially and
for consumers. It's usually used for making things stick, so as a powder that
you can rub on your hands when doing rock climbing, playing baseball,
what-have you. It's generally advertised as gum rosin, which is made from sap
collected from pine trees, but there's also wood rosin, which is made from
grinding up the tree roots after harvesting the pine. I believe they're the
same, but I've only ever bought gum rosin. Please be sure to only buy rosin
that's certified free of angry bees.
</p>
<p>
The vaseline comes from the supermarket. Bunnings sells isopropyl alcohol.
</p>
<p><b>Method:</b></p>
<p>
Combine the rosin and vaseline in a 48ml Kilner hexagonal preserve jar. Break
up the rosin if necessary to get it into the mouth of the jar.
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhglbU-EV6osV00RVPW2H1kRHoe96Y9MoIpDaFXBMOvnobiX5uWZOAnVWPt43uid2IRcV0Qe9icdFS43MRrFSJAWGz85Ju2FmgqXDZaXj6dSbxiPohui-NVdj3VO_VvNVrKQ_FL96Sm9C8/s1280/IMG_1513.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="960"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhglbU-EV6osV00RVPW2H1kRHoe96Y9MoIpDaFXBMOvnobiX5uWZOAnVWPt43uid2IRcV0Qe9icdFS43MRrFSJAWGz85Ju2FmgqXDZaXj6dSbxiPohui-NVdj3VO_VvNVrKQ_FL96Sm9C8/s600/IMG_1513.jpeg"
/></a>
</div>
<p>
Heat the mixture in the oven at 120˚C for about 20 minutes. The rosin will
melt and form a thick treacle layer under the vaseline, which will go
perfectly clear.
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_gdSl6FGB9DN0wScfwFCfIcOQVsEUAr9GZBYSGkcb-0Tx01FDEeWFga5gWn_gJ8M03j8WVTMMM4EJBwD7fiudmsNmZd_0ENg6vc88s2PU5TTOqFwjvDqhnFEd7DC6F-NPhVnbymfOQOY/s1280/IMG_1514.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="894"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_gdSl6FGB9DN0wScfwFCfIcOQVsEUAr9GZBYSGkcb-0Tx01FDEeWFga5gWn_gJ8M03j8WVTMMM4EJBwD7fiudmsNmZd_0ENg6vc88s2PU5TTOqFwjvDqhnFEd7DC6F-NPhVnbymfOQOY/s600/IMG_1514.jpeg"
/></a>
</div>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiw8MI1BA0Tql-0ih4JgZTgFlSbwJtcvm4HAo7sx531YT1JLouqYi6D5yGCZUO4_sJpFaU43j7QSlJk8somHqa3AlMTeqeZztS9h2jEjthqaPr5VOaUfwdyR3VX63Ax2wMJSFjzIQ94xG4/s1280/IMG_1515.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="963"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiw8MI1BA0Tql-0ih4JgZTgFlSbwJtcvm4HAo7sx531YT1JLouqYi6D5yGCZUO4_sJpFaU43j7QSlJk8somHqa3AlMTeqeZztS9h2jEjthqaPr5VOaUfwdyR3VX63Ax2wMJSFjzIQ94xG4/s600/IMG_1515.jpeg"
/></a>
</div>
<p>Pull it out and stir to combine layers with a paddle-pop stick.</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTvQIeVtXzcBB-FndpSrGVY6q-iKJ0U-mLWLapeWNYSHG5xenAGI_ws3nWACjk9s2TUNWgjvQroG2ae9xQfStMYWWHeVT1VI7nOTXAZKhEcPOF56Xhn7xaRzN-0SOfanqQLEbky1fFxIk/s1280/IMG_1516.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="1022"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTvQIeVtXzcBB-FndpSrGVY6q-iKJ0U-mLWLapeWNYSHG5xenAGI_ws3nWACjk9s2TUNWgjvQroG2ae9xQfStMYWWHeVT1VI7nOTXAZKhEcPOF56Xhn7xaRzN-0SOfanqQLEbky1fFxIk/s600/IMG_1516.jpeg"
/></a>
</div>
<p>
Pop it back in the oven for another few minutes, to encourage any trapped air
bubbles to rise to the surface.
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTIaJ1p6w-NPPo8yD7EHwxxn5-0k9dJ_g9fDprfFxoILuKu9-HRUo8K40qwhbF7Q02cq9OclqWLZ-Kg7cXmoIFdZeE4YMiBLa-ZQ1osZPDeCq42O2Qi7LouCdIj5POCEi-27rdqVBSn2M/s1280/IMG_1517.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="960"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTIaJ1p6w-NPPo8yD7EHwxxn5-0k9dJ_g9fDprfFxoILuKu9-HRUo8K40qwhbF7Q02cq9OclqWLZ-Kg7cXmoIFdZeE4YMiBLa-ZQ1osZPDeCq42O2Qi7LouCdIj5POCEi-27rdqVBSn2M/s600/IMG_1517.jpeg"
/></a>
</div>
<p>
Take it out of the oven and let it cool for ten minutes or so before sucking
into syringes, if that's your preferred dispense method. I find if I leave it
too long it thickens up and is hard to draw into the syringe.
</p>
<div class="separator" style="clear: both;">
<a
href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH2fcgR17Ir5Yv_30_NTmf3o4FFQ_4KoBzHgnO9B7yB7UdnvqyKxpSah0MqBXK-rTMhILGhiVVhg08DFvSm04XTXESITlkt8dLOND9-sipg3xx9DGnA-Dw25_emI-7fziPHCxRp45vyx8/s1280/IMG_1518.jpeg"
style="display: block; padding: 1em 0; text-align: center; "
><img
alt=""
border="0"
width="600"
data-original-height="960"
data-original-width="1280"
src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjH2fcgR17Ir5Yv_30_NTmf3o4FFQ_4KoBzHgnO9B7yB7UdnvqyKxpSah0MqBXK-rTMhILGhiVVhg08DFvSm04XTXESITlkt8dLOND9-sipg3xx9DGnA-Dw25_emI-7fziPHCxRp45vyx8/s600/IMG_1518.jpeg"
/></a>
</div>
<p>
If you find it's too thick, you can add a few percent isopropyl alcohol.
Isopropyl is the solvent in liquid flux, and it's probably also the solvent
you use for cleaning up your boards after assembly. Go easy on the isopropyl
though. As well as thinning the flux quite well, it also boils off very
rapidly on the PCB when you solder, resulting in spitting when you apply the
iron if you overdo it. I find the best time to add the isoproply is as the
mixture is cooling. It's easy to stir in then. Don't do it too soon after
taking it out of the oven though, as the temperature initially is above the
boiling point of the isopropyl, so you'll only waste it.
</p>
<p>
You can reheat the flux multiple times to get it just how you like. Warm it up
to 50˚C or so, so it's runny. Add a little isopropyl. Let it cool. If you
overdo the isopropyl then just warm it up over 80˚C, and the isopropyl will
start to boil off.
</p>
<p>
The stuff in the jar, or in the syringe, is just a lot of rosin in suspension
in the vaseline. When you heat that mixture, two things happen. Firstly the
rosin melts. It flows over the joint and does the good things that the rosin
does. The vaseline has a boiling point of around 300˚C, so a good amount of it
will boil off. This is mostly what you get in the little wisps of smoke that
come off the iron, plus of course some rosin that's caught up. It's not good
to inhale, so use some fume extraction. It doesn't have to be fancy. A simple
muffin fan sitting near to the work on the bench is usually plenty. If you
must use RMA or RA flux rather than straight rosin, definitely use fume
extraction because ingesting the acids is not at all good for your lungs.
</p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com6tag:blogger.com,1999:blog-924768814112596827.post-46827099055090243912020-12-20T11:39:00.002+08:002020-12-20T11:39:59.190+08:00A new tow vehicle for ElenaMy old pug that used to tow Elena became very unreliable, with crankshaft position sensor errors and other sundry issues cropping up regularly. Its age was such that we were going to have to do timing belt and particulate filter, and there was a fair bit of panel damage from an intimate encounter with a roo. So when rego came due last year we took it to the wreckers.<p>
Since then we haven't had a car with a towbar.<p>
I've been talking about getting a ute for ages, and recently my main car has been off the road (another roo), so we brought that forward. Top of the list was something that could comfortably tow Elena. I also wanted something that would be good for picking up piles of wood for the next boat. I decided something with a tray 2.4m long would be perfect, as so much wood comes in 2.4m lengths. Also I didn't want to spend too much, as it's a second car and will have it's arse dipped in the water occasionally.<p>
So meet our new ute. It's a bottom of the range Mitsubishi Triton single cab, with a tray. It's a 2011 model, with 120,000km and is as simple as a vehicle can be. And it's just the ticket for towing Elena.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6jK8C9TSwOxtdsXf7qy3cG7Gq_5sJ61K-OrRm1z3ZD6fuL-Wj9QNL7Uv6gzNdA3xw1oyVuPJ9a4y7dl3rGwYIgRjXEXVLHolqg62Q7kmCAMaQeVo7gzj6Sltb8-ji-Pug9mYttHkWXjc/s2048/8CECBFD6-824A-464B-A263-B07C662C25C4.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1151" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6jK8C9TSwOxtdsXf7qy3cG7Gq_5sJ61K-OrRm1z3ZD6fuL-Wj9QNL7Uv6gzNdA3xw1oyVuPJ9a4y7dl3rGwYIgRjXEXVLHolqg62Q7kmCAMaQeVo7gzj6Sltb8-ji-Pug9mYttHkWXjc/s600/8CECBFD6-824A-464B-A263-B07C662C25C4.jpeg"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrV991MuVuyYVJ25fjihm3-j0oJcmQGfl_6UyhWWvbLsjmRSn0Pt1bOM49NhXkYaBv_PGqPOOdfkfAt2hiCP1VLjanCyVV_sccARpOUYr_FIpfCGa14enPhaWXyclbHjPjaaQtW8QM7dI/s2048/44F46252-E4C4-4B8C-AE0C-95DF98C1CC08.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1152" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrV991MuVuyYVJ25fjihm3-j0oJcmQGfl_6UyhWWvbLsjmRSn0Pt1bOM49NhXkYaBv_PGqPOOdfkfAt2hiCP1VLjanCyVV_sccARpOUYr_FIpfCGa14enPhaWXyclbHjPjaaQtW8QM7dI/s600/44F46252-E4C4-4B8C-AE0C-95DF98C1CC08.jpeg"/></a></div>
I've come up with a simple method of securing the mast so it doesn't scuff the floor, just by hanging it between the aft mooring cleats. I'll sew bags for the rest of the bits.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtmMtXK3eYccoKCDKBSaJJ9Uz_pPTBnV_AGA3TfzXy38RE0N6AJfFLNc2Wz_qsFP6lVsE44I6_txSe5Hladh8LvP2jK6jPihmDMOU5AISf1p5L0fwx5Pik91WcJhFaityIAXZlih2ppIc/s2048/8E7CA2E2-F4E5-473B-8178-1E41B4F884C2.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtmMtXK3eYccoKCDKBSaJJ9Uz_pPTBnV_AGA3TfzXy38RE0N6AJfFLNc2Wz_qsFP6lVsE44I6_txSe5Hladh8LvP2jK6jPihmDMOU5AISf1p5L0fwx5Pik91WcJhFaityIAXZlih2ppIc/s600/8E7CA2E2-F4E5-473B-8178-1E41B4F884C2.jpeg"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvYq16CesaZjZoyikHcn7IB0cYsCUsHzUP1OGFEsnrMdfDnm5Yralmf-d4S02HYx-F71bVvcnMH7g955MX76_F4nIHUW1VQMl0ASzFexc4OK5zot-z7CTH5A6Go8qS1mP5IT-ZSsXosfs/s2048/E9B1C300-55CF-4C41-AD1A-0D5C1405D7DC.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvYq16CesaZjZoyikHcn7IB0cYsCUsHzUP1OGFEsnrMdfDnm5Yralmf-d4S02HYx-F71bVvcnMH7g955MX76_F4nIHUW1VQMl0ASzFexc4OK5zot-z7CTH5A6Go8qS1mP5IT-ZSsXosfs/s600/E9B1C300-55CF-4C41-AD1A-0D5C1405D7DC.jpeg"/></a></div><div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ2M6_fCVCQT_P0wbVumrdmQLngbbCayfvmG6zzEYvCVMS0c5MM3QjdOaJTBeYNMONWetwuUX5Q4PL7XUH_q6qS2S6iRgwZB9mCr6Dl9AJsfb0yKwu92Pfsda6FTJ9K8EV2_kWkYmNMmc/s2048/FDF486E2-39C0-4184-8DE2-9938FFE85EA4.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ2M6_fCVCQT_P0wbVumrdmQLngbbCayfvmG6zzEYvCVMS0c5MM3QjdOaJTBeYNMONWetwuUX5Q4PL7XUH_q6qS2S6iRgwZB9mCr6Dl9AJsfb0yKwu92Pfsda6FTJ9K8EV2_kWkYmNMmc/s600/FDF486E2-39C0-4184-8DE2-9938FFE85EA4.jpeg"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-83049831743618729322020-12-08T07:00:00.003+08:002020-12-11T13:20:28.240+08:00AEM6000 Based 50W and 100W AmpsThis is a design I've had in use for rather a long time. It started life as a design exercise to see if I could do a more space-efficient board for my original AEM6000 based amps, as I wanted something that would fit on a 50mm high heatsink. Along the way it changed a little from Tilbrook's original in topology, and rather a lot in component choice. It has better performance than my original design, both through a better tighter layout and also through the use of faster transistors.<p>
I've built a bunch of these, using both Renesas and Exicon lateral MOSFETs, and subjected them to all manner of abuse. I had one fail, due to a leaky mica compensation capacitor (see noiseUnit speaker thread), but apart from that they've been rock-solid.<p>
Lots of component substitution is reasonable. I like to use MELF resistors, but that's mostly just bloody-mindedness. An exception is the feedback divider. No, It won't work with cheap vertical MOSFETs.<p>
The design is free for use for non-commercial purposes.<p>
The 50W design is available on <a href="https://drive.google.com/file/d/1Z64oyJk0Gk6AeITYEV_hNOe5yOIapLIH/view?usp=sharing">my Google drive</a><p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0M9_Zf7ethqXerRsdW0ldHA0nKebZjz6cm5BfKvLPGyjC2xgpaAGA2nviJ2n-kmfUr5ac5-ZesWcCnOYIFsiGlHYrWgyv55gZCxdUfV3HBb-vZNxY5iKPg0H9h-L5omflmkhWEXEX52E/s1280/IMG_1420.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0M9_Zf7ethqXerRsdW0ldHA0nKebZjz6cm5BfKvLPGyjC2xgpaAGA2nviJ2n-kmfUr5ac5-ZesWcCnOYIFsiGlHYrWgyv55gZCxdUfV3HBb-vZNxY5iKPg0H9h-L5omflmkhWEXEX52E/s600/IMG_1420.jpeg"/></a></div>
The 100W design is available on <a href="https://drive.google.com/file/d/1gmLff4ARccPZOPhQ61nygGyPJGoeAeVt/view?usp=sharing">my Google drive</a><p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwRkgPf8YOlxbj3MsM3HFeEFuuoTOSq8_ys6Icb936h2s8jGaYHhtpNfuHIleNbQ46pDj8wmWeG84cYi8x8hkUbGqQne3WCMkXBlTM4r-izixUQKO-8tAcLaq_sDS5EN7MoOngxjE85ZI/s1280/IMG_1423.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="735" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwRkgPf8YOlxbj3MsM3HFeEFuuoTOSq8_ys6Icb936h2s8jGaYHhtpNfuHIleNbQ46pDj8wmWeG84cYi8x8hkUbGqQne3WCMkXBlTM4r-izixUQKO-8tAcLaq_sDS5EN7MoOngxjE85ZI/s600/IMG_1423.jpeg"/></a></div>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-37199430755965923382020-11-19T06:19:00.001+08:002020-11-19T06:19:48.683+08:00Tektronix TDS-340a CROA mansplainer on DIYAudio just told me my TDS-340a has an LCD, not a CRT.<p>
This photo is to put him in his place.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvqxfAy056LKjzcOm44REQNMAAX36mklxZJU79fG1UoIYD_gtYhL_W8pLxyG-f1NG1SyOewXp3OaPh045BM2Or_4RLWQTAcZTFuS_glkm4HUq0THTS661SfepgLwZ96eadGOGNLYbdKow/s1280/FB1DCDC6-7229-43C5-BC4A-338961FF38B6.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvqxfAy056LKjzcOm44REQNMAAX36mklxZJU79fG1UoIYD_gtYhL_W8pLxyG-f1NG1SyOewXp3OaPh045BM2Or_4RLWQTAcZTFuS_glkm4HUq0THTS661SfepgLwZ96eadGOGNLYbdKow/s600/FB1DCDC6-7229-43C5-BC4A-338961FF38B6.jpeg"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-91727616849341608742020-11-14T14:30:00.003+08:002020-11-14T14:48:48.441+08:00Building the Per-Anders Sjöström QSXM2I don't always just build my own toys. When other designers make really beautiful kit, I buy their PCBs and go to town.<p>
Such is the case with a few of Per-Anders' designs. He and I share a common design rationalle, which can best be summed up as "components are cheap, if more of them makes it perform better, go for it!".<p>
A perfect example is the QSXM2 phono preamp. Something like 200 resistors, 110 transistors, around 100 caps. It's really not mucking around. It's a preamp that leaves no stone unturned in the search for performance. I'm keen to see if I can improve on the basic phono pre in my NAD3240PE, and this one looks like a very good candidate. I've built some othe Per-Anders designs (mainly head-amps), and have been very impressed.<p>
So I ordered a PCB from <a href="https://sjostromaudio.net/cart/en/pre-amplifiers-line-circuits/26-qsxm2-ultra-extreme-riaa-amplifier.html">his website</a>, downloaded the design doco, and started work:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimZh71gjnzmbIDsW2vjjJ9ypiXb7ehTNtticOsVI8Bw4nOYaSlObKMX7p95ugWQRzBv-dMdp9xaGFVArs3Jh9YiTeue0z83QLNyWkWItXT4hOfHPy_Th6ZaXjzZ_h8X9UrNY36Il-2yNw/s2048/541D1907-88FE-441A-A571-069165F95F94.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEimZh71gjnzmbIDsW2vjjJ9ypiXb7ehTNtticOsVI8Bw4nOYaSlObKMX7p95ugWQRzBv-dMdp9xaGFVArs3Jh9YiTeue0z83QLNyWkWItXT4hOfHPy_Th6ZaXjzZ_h8X9UrNY36Il-2yNw/s600/541D1907-88FE-441A-A571-069165F95F94.jpeg"/></a></div>
I've set my work area up with a nice new A2 cutting mat, which protects it from the soldering iron and scratches. There's no need for the microscope for this guy, as it's all through-hole.<p>
So far I've done all the resistors (I had comprehensive stocks, which will now need to be replenished), and I'm on to the caps, many of which I'll have to order in.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD67TsFaayHTNv-d-zh_4Q2srL5i12RC0kCKbEm7CihaZ_C1p1BEIysuy-yQZqKp4Nc8P2ih158PxXp_nV3Ud7oIiZifF5uHpsLczxGxVtjlka4cbJ0KlqsMArcKnwmfp7R8isX6NFL8g/s2048/DF134647-422A-4672-AA21-4845E4A2AE76.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1476" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD67TsFaayHTNv-d-zh_4Q2srL5i12RC0kCKbEm7CihaZ_C1p1BEIysuy-yQZqKp4Nc8P2ih158PxXp_nV3Ud7oIiZifF5uHpsLczxGxVtjlka4cbJ0KlqsMArcKnwmfp7R8isX6NFL8g/s600/DF134647-422A-4672-AA21-4845E4A2AE76.jpeg"/></a></div>
I'm looking forward to trying it out!<p>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com5tag:blogger.com,1999:blog-924768814112596827.post-80947408935788101092020-11-08T17:56:00.001+08:002020-11-08T17:56:26.694+08:00Annual HP 3585B stinky capacitor huntOne of the hazards of using elderly test equipment, such as my HP 3585B, is old capacitors. HP loved using tantalums, which while having great low ESR, are also teensy little time bombs. Occasionally (typically at turn-on) there's a stink, and that's the sign that another one has let go.<p>
So this happened the other day, and I spent a couple of hours sniffing the little blighter out, quite literally, as they're quite pongy and your nose is a great diagnostic tool.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdteQ8IzT4s1_SbECDxPg0UWyZI91Gm2jCeTDQfwXUV-GFmygqbowlgoalnPrST9c5JKOuvecdi1hZQ87YEdRvBJ1JqpN6f1hemGRxfc4d0jgqloY1aJAgR8aY-1-pEhZT5Pye7jP5wd8/s2048/CCD8F33B-A0D4-42C8-9435-296AB099B777.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdteQ8IzT4s1_SbECDxPg0UWyZI91Gm2jCeTDQfwXUV-GFmygqbowlgoalnPrST9c5JKOuvecdi1hZQ87YEdRvBJ1JqpN6f1hemGRxfc4d0jgqloY1aJAgR8aY-1-pEhZT5Pye7jP5wd8/s600/CCD8F33B-A0D4-42C8-9435-296AB099B777.jpeg"/></a></div>
This is quite a beast of a spec-an, weighing in at around 35kg. It's really beautifully made, with gold plated circuit boards. I started by pulling boards one at a time and giving them a quick once-over.<p>
Eventually I found it, at the back of the input module on the underside of the unit.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTA2bXUxpasCD6_byl_ZNXnzmGNXsGeE-zFsRA3Fd70V_443iBm_k-iB8t3uwzvdhLuTrBj3_rGWcQtMJmvOqm5WKOIv60BQp1-R6VhfXSmgCP89Fa4CYWmdBIEgP63Z3E_iH0YkGsVYY/s2048/D34DA911-8EB4-4DFA-84F5-953AD2F542D0.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTA2bXUxpasCD6_byl_ZNXnzmGNXsGeE-zFsRA3Fd70V_443iBm_k-iB8t3uwzvdhLuTrBj3_rGWcQtMJmvOqm5WKOIv60BQp1-R6VhfXSmgCP89Fa4CYWmdBIEgP63Z3E_iH0YkGsVYY/s600/D34DA911-8EB4-4DFA-84F5-953AD2F542D0.jpeg"/></a></div>
This one is a little 2μ2 20V Kemet axial tantalum. Luckily I have a few in a drawer. So I whipped it out and popped a new one in, and now it's good as new (until next time).<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYPxoAhEdRVem7rN3e3m2ABAGC1HCeByxzd5l7C0UKN2yp61I7LglBr9WA19Oeixb_vfFKdkCVSmKuynf6o18z0MoIc_QJhkp9gk2JjvY963TVAjgdg7njcOYkgiLW7m05zfADhcx-EQA/s2048/8F11845C-D8D4-4BDE-B21E-13F6756F21E0.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYPxoAhEdRVem7rN3e3m2ABAGC1HCeByxzd5l7C0UKN2yp61I7LglBr9WA19Oeixb_vfFKdkCVSmKuynf6o18z0MoIc_QJhkp9gk2JjvY963TVAjgdg7njcOYkgiLW7m05zfADhcx-EQA/s600/8F11845C-D8D4-4BDE-B21E-13F6756F21E0.jpeg"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-75909252869996549682020-10-31T15:34:00.000+08:002020-10-31T15:34:04.009+08:00NAD L70 receiver refreshOn the bench today is a NAD L70 receiver. It's a bit newer than the stuff I generally like to work on with NAD, but it was going really cheap, and is cosmetically pristine, so I thought I'd have a play.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUozcsUuBYbSxDduKUwLyMqhnu7jxCdJ_Wc8LPuUtRCJ5DvMsd4tBPhrhsBQfpQiK2Vi-IXAMF6X0ygDGytfvIBGHCPffZMNjSBX_CifSyEmGBjrHGwarfOkBNCdVn1KyyDOSDi_-5As0/s1280/IMG_1222.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUozcsUuBYbSxDduKUwLyMqhnu7jxCdJ_Wc8LPuUtRCJ5DvMsd4tBPhrhsBQfpQiK2Vi-IXAMF6X0ygDGytfvIBGHCPffZMNjSBX_CifSyEmGBjrHGwarfOkBNCdVn1KyyDOSDi_-5As0/s600/IMG_1222.jpeg"/></a></div>
There were two symptoms of bad behaviour. Firstly, a truly dreadful hum present in both channels, and secondly the CD/DVD player was really flaky, reporting "no disc" as often as not, and pausing and stuttering quite a lot while playing when I could get it to recognise a disc.<p>
On opening it up it was really obvious what was causing the hum. There are 4 large capacitors on the top (CPU) board, that provide smoothing for all the lower voltage DC supplies. A couple of these were obviously bulging. So I whipped all four out and replaced them with 2200µf 25V 105˚ Panasonic electrolytics. While I was there I replaced a bunch of the smaller caps nearby.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGaokJbUMhkJjFksjew2tHOeIcwjkyNCtC6GqoPoZSR0pVRodUA75lqRMG0-yltH2pXujBBW8aktTRwJkU564_Hr6aGXJO5YgpLFzetYna7_HQVLXtcY4pyP8cDov_llohXYM_0HHQsFs/s1280/IMG_1223.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGaokJbUMhkJjFksjew2tHOeIcwjkyNCtC6GqoPoZSR0pVRodUA75lqRMG0-yltH2pXujBBW8aktTRwJkU564_Hr6aGXJO5YgpLFzetYna7_HQVLXtcY4pyP8cDov_llohXYM_0HHQsFs/s600/IMG_1223.jpeg"/></a></div>
That sorted the hum. Next up was the misbehaving CD/DVD player.<p>
This is a real bear to get to, being underneath the CPU board. In order to get the transport out you have to first open the tray and unclip the oval NAD bit on the front. Then retract the tray again, open the cover, remove the CPU board, and it's pretty obvious.<p>
The transport is an ATAPI/IDE one, made by Raymedia (RMC) part number RL-A700. This is common to a lot of CD, DVD, and SACD players of the period.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEX_fL9MrrJUceAmFm5ZqAYCSN2bk-6qkLJwbsyFV8bwYtTQl3hXl91rWfNGaHGNMYrUzt3PYY4GPKxa3jZ25F8K9TANy1_3B3Ye4oLsI6U_DHCUcEqnGlapMTLGu_l4En2Ue0CUs2xlE/s1280/IMG_1064.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEX_fL9MrrJUceAmFm5ZqAYCSN2bk-6qkLJwbsyFV8bwYtTQl3hXl91rWfNGaHGNMYrUzt3PYY4GPKxa3jZ25F8K9TANy1_3B3Ye4oLsI6U_DHCUcEqnGlapMTLGu_l4En2Ue0CUs2xlE/s600/IMG_1064.jpeg"/></a></div>
Once the transport was out, I started by popping the top cover off and giving the lens a wipe with a kimwipe and a little isopropyl. I cleaned the dried grease off the sled slides and gears, and relubed with Electrolube Special Plastics Grease (SPG), which is just for this.<p>
Cleaning didn't help. The supplies were tested good, and this transport really has nothing to adjust, so I next ordered a replacement pickup. Part number for the pickup is SF-HD60.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5liLSSnrwOGa8ZtBnlM0No_iNqS8Qs9cw0uZ7QNlc41LKdMaMLBUqlvP2tz0aJ0GpZjKe7pnYNcSex1QrAQ9BwsEl3f2vKzYrSZoE7TiYWlx_uiFr1L7KXRCPqL5bSAAu4SCe8_I9K24/s1280/IMG_1224.jpeg" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="960" data-original-width="1280" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5liLSSnrwOGa8ZtBnlM0No_iNqS8Qs9cw0uZ7QNlc41LKdMaMLBUqlvP2tz0aJ0GpZjKe7pnYNcSex1QrAQ9BwsEl3f2vKzYrSZoE7TiYWlx_uiFr1L7KXRCPqL5bSAAu4SCe8_I9K24/s600/IMG_1224.jpeg"/></a></div>
It arrived after a couple of months, and I fitted it today, removing the anti-static solder blob after fitting.<p>
This made a really big improvement, but it still stalls very occasionally and 2 or 3% of the discs I've tried today don't read. After repeating the clean, relube, reassemble, test cycle a couple of times, including pulling the spindle motor and giving that a bit of a spray of iso (did I mention that it's a pain to get to the transport under the CPU board), I've decided to bite the bullet and just order a whole new transport for it.<p>
So that's where this one is at. It actually sounds really good, and with the exception of three useless channels will make a lovely all-in-one stereo. I think I'll set it up in my office at work once it's finished.<p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com1tag:blogger.com,1999:blog-924768814112596827.post-2350535515505735482020-10-06T11:23:00.004+08:002020-10-06T17:22:22.606+08:00Telegraph Roads - an objective comparison of Dire Straits - Love Over Gold in various formats.I really do love Dire Straits. Perhaps my favourite Dire Straits album is Love Over Gold. There's a bunch of reasons I love it; it's melodically beautifully put together, there's a nice variety of different styles, and most importantly it was released in '82, when I was at the tender age of eleven, so I played it rather a lot as an impressionable teen. A whole lot of synapses in my brain are dedicated to this album.<p>
So I've had it in various formats over the years. Originally in the '82 issue Australian pressed LP (Vertigo 6359 109/4), slightly more recently on the original Australian CD (Vertigo 800 088-2), the 1996 remaster (annoyingly also 800 088-2, but copyright '96 rather than '82) and most recently on the Japanese SHM-SACD (UIGY-9637) which is generally well regarded by audiophiles.<p>
I'll stick to the very first track, Telegraph Road. It's 14 minutes 20 of really good music.<p>
Before I start, all my versions sound pretty good. Telegraph road is one of the most engaging, haunting pieces of music I know of, and they're all good copies. My LP and original release CD, though old, are very well loved and looked after. My SACD version is brand-new. I cannot tell whether the original CD or SACD is playing, and I honestly can only tell the LP because of the pops and crackles. I can tell the difference with the 1996 CD though - it's louder. I've always really enjoyed the LP. It's probably simply because of the tactile nature of the medium, and the way I sit down in a nice quiet room to listen on a reasonably good stereo, but it has character that I enjoy. But these are subjective evaluations, not objective ones. They deal with my emotions, which are coloured by handling the album in the format in which I first played it. And subjective evaluations are easy to fake.<p>
To evaluate the various versions I first import them into my mac. For that I use a variety of different things, and they are different depending on the medium.<p>
For the LP, I play the LP on a NAD-5120 turntable (one of the later ones with a more conventional tonearm), with Goldring Epic-II moving magnet cartridge at 2.0g force. I run it through the phono amp and preamp in one of my NAD3240PE integrated amplifiers (why yes, I do have a couple of these wonderfully temperamental beasts), then to a Roland FA-77 firewire ADC, then to my mac. I run the ADC at 44.1ksps, 24 bit. The turntable, cartridge, and amplifier, while nothing to write home about, are representative of the better quality but not esoteric kit that was available in the 1980s. It's not the gear that I listened to the album on as a teenager. My parent's HiFi was a Kenwood one (with graphic equaliser!) and I actually only listened to the LP the once, while recording it to tape at 7 1/2" per second on our Akai cross-field reel deck. I was a weird kid, and I'm a weird adult.<p>
For the CDs, I simply rip using itunes on the mac and a CD drive. I save the file as 44.1ksps 16 bit PCM, uncompressed.<p>
I have no way of directly transferring the DSD stream from the SACD, so I go via analogue. I use a Sony UBP-X700 4K blu-ray player (which plays SACD contant), to a NAD D1050 DAC, then to my Roland FA-66 ADC, then to the mac. As with the LP, I digitise at 44.1ksps, 24 bit.<p>
Let's work our way through the copies in chronological order. First, the LP. I started this expecting to see a gradual improvement with better equipment, but in reality it's quite a lot more subtle than that.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp1pCOgNc04waNQHxGfMwDU81W_ige-lSqUaA3dkncnj2GvwNPWVhoycsmTqQgfftN5v-ZdV97UCIyHoypdcnAEiE0JgvgWVOKKNE86r0VZNwyLM9mUqZxpDY0kcxbaopVQFwkGqlrk1c/s2048/Screen+Shot+2020-10-06+at+8.50.33+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1078" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgp1pCOgNc04waNQHxGfMwDU81W_ige-lSqUaA3dkncnj2GvwNPWVhoycsmTqQgfftN5v-ZdV97UCIyHoypdcnAEiE0JgvgWVOKKNE86r0VZNwyLM9mUqZxpDY0kcxbaopVQFwkGqlrk1c/s600/Screen+Shot+2020-10-06+at+8.50.33+am.png"/></a></div>
I've trimmed the track to 14 minutes, 22 seconds. The official length is 14 minutes 20 seconds, but I've left perhaps a second either side. When digitised, I kept the gain such that it never clipped. Then I used the Audacity amplify tool to amplify it to 0.1dB from clipping (3.6dB gain, for what it's worth).<p>
The resulting audio reports the following dynamic range in the MAAT DR Offline Meter:<p>
Dynamic Range: Left 12.52dB, Right 12.47dB<br>
Peak: Left -0.70dB, Right -0.10dB<br>
RMS: Left -17.87dB, Right -17.63dB<p>
MAAT reports the DR as 12, which is generally accepted as very good. I've seen reports of 13 for this track on the original 1982 LP. I may be able to do better with a better cartridge and phono amp. Also I've done nothing yet to clean up the clicks and pops, which may be colouring the result a little.<p>
So next the 1982 CD. I did nothing to the file. Just imported it into Audacity for viewing and ran it through the DR meter as-is.<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp7KJoGlM5H8M-SoPOfT45BbMeMSXTGTOZs5JI0GEgvSP46g0NosZp0GzQaht7nuFpDcYjQ_wxt6A013r6ctRbFDgKXxNOcrHATTGiXi0ZwhyphenhyphenCKbCUxZxdOSQ33v6AgjPuDzfx5Q8c0XQ/s2048/Screen+Shot+2020-10-06+at+7.19.55+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1075" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp7KJoGlM5H8M-SoPOfT45BbMeMSXTGTOZs5JI0GEgvSP46g0NosZp0GzQaht7nuFpDcYjQ_wxt6A013r6ctRbFDgKXxNOcrHATTGiXi0ZwhyphenhyphenCKbCUxZxdOSQ33v6AgjPuDzfx5Q8c0XQ/s600/Screen+Shot+2020-10-06+at+7.19.55+am.png"/></a></div>
This looks similar to the LP at this level of zoom, which is nice. I note there's a bit of a fade in applied to the first 20 seconds or so.<p>
MAAT DR Offline Meter reports the following:<p>
Dynamic Range: Left 13.40dB, Right 13.09dB<br>
Peak: Left -0.11dB, Right over<br>
RMS: Left -17.95dB, Right -17.06dB<p>
This is a better result than the LP, with close to a dB better dynamic range.<p>
Now for the 1996 "remastered" CD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeJ3Z9-vcusfLFUxExV3SjH1ixeVnlbRZuZ8y_tHTElkKRDblkZGstyuz5nGIma-jTlhI7_kxg7sR6nsHMkolDHxgmlSP76zLvK3PiCavjxdObBmPaqFhv3mDDmmnBxtVEdSlsk8cnjUY/s2048/Screen+Shot+2020-10-06+at+7.27.01+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1081" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeJ3Z9-vcusfLFUxExV3SjH1ixeVnlbRZuZ8y_tHTElkKRDblkZGstyuz5nGIma-jTlhI7_kxg7sR6nsHMkolDHxgmlSP76zLvK3PiCavjxdObBmPaqFhv3mDDmmnBxtVEdSlsk8cnjUY/s600/Screen+Shot+2020-10-06+at+7.27.01+am.png"/></a></div>
MAAT DR Offline Meter reports the following:<p>
Dynamic Range: Left 10.34dB, Right 9.89dB<br>
Peak: Left -0.00dB, Right over<br>
RMS: Left -14.31dB, Right -13.96dB<p>
It's pretty obvious to see why this isn't a well-regarded mix. It's certainly subjectively louder than the originals, but that's because of judicious use of compression. Alas the '90's were awash with this sort of awful treatment of audio.<p>
Finally we come to the "definitive" 2014 SACD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiow3cYWdWGssWri9TQWcfnNs73Z8tTyWgcCATqJ-laZidK1z5tQQ650DAn_37ejs0iQdqnJHJlYcPr1DUtobNcghrM541t8_Gf65E23eD3q_n3Ho43hdhg5k7pc0D4MvAtbsh6A45Pa8Y/s2048/Screen+Shot+2020-10-06+at+7.16.30+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1081" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiow3cYWdWGssWri9TQWcfnNs73Z8tTyWgcCATqJ-laZidK1z5tQQ650DAn_37ejs0iQdqnJHJlYcPr1DUtobNcghrM541t8_Gf65E23eD3q_n3Ho43hdhg5k7pc0D4MvAtbsh6A45Pa8Y/s600/Screen+Shot+2020-10-06+at+7.16.30+am.png"/></a></div>
This is interesting when compared to the original LP and CD. Note the gradual increase in gain during the final instrumental passage, up to around 1.5dB for the finale.<p>
MAAT DR Offline Meter reports the following:<p>
Dynamic Range: Left 13.91dB, Right 13.68dB<br>
Peak: Left -0.38dB, Right -0.00dB<br>
RMS: Left -19.27dB, Right -18.50dB<p>
I keep looking at the fiddling to the end of the instrumental passage. Could this simply be a cynical attempt to fudge the DR readings? Could the record industry really be that blatant?<p>
What happens if I undo this? On a whim I applied a fade-out of 1.1dB from 11 minutes onwards (I actually added silence to 22 minutes, then selected the audio from 11 minutes to 22, and used the "studio fade out" effect in Audacity, then amplified back to -0.1dB peak:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivnN74CdI0ccL34eQucwR9s9lX0vNqm7Woat5Q1wiby2Bu0FS3aVEtT2LYawL5cIMITty22xWg_8OsuJNVooHsAYiyHeEHvNn5Y-UTKx1RM8DQBhTcYDEOb-T1zjcNuHt0eRbZjPzoPTs/s2048/Screen+Shot+2020-10-06+at+9.54.26+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1079" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEivnN74CdI0ccL34eQucwR9s9lX0vNqm7Woat5Q1wiby2Bu0FS3aVEtT2LYawL5cIMITty22xWg_8OsuJNVooHsAYiyHeEHvNn5Y-UTKx1RM8DQBhTcYDEOb-T1zjcNuHt0eRbZjPzoPTs/s600/Screen+Shot+2020-10-06+at+9.54.26+am.png"/></a></div>
So now it looks... Pletty much exactly like the 1982 CD. MAAT DR Offline Meter reports the following for my "un-tweaked" version:<p>
Dynamic Range: Left 13.37dB, Right 13.18dB<br>
Peak: Left -0.73dB, Right over<br>
RMS: Left -18.55dB, Right -17.81dB<p>
Which is very close (we're talking within 0.1dB) to the 1982 CD. Enough so that I'm wondering if perhaps this isn't the extent of the "remastering"?<p>
So, what to say? In raw numbers, the SACD wins. But only, I feel, because they cheated. Discounting the cheat the 1982 CD is the winner.<p>
So that's a "whole of track" view showing the really loud bits. One of the really engaging things about this track is the very quiet bits between passages. These don't affect the overall dynamic range figures terribly much, as they're derived by simply taking the difference of the whole-of-track RMS vs peak. If a quiet passage is a few seconds long, it won't have much impact on a 14 minute track. Sections of silence, or near silence, stretch the medium, and are a good indicator of a really good recording. CD should have an overall signal to noise ratio of 96dB, so we should be limited entirely by what the original (analogue) tapes could manage.<p>
The bit I'm interested in comes immediately after the line "There's six lanes of traffic, three lanes moving slow" at about 5:10 into the track. It moves around a little on the various recordings due to small changes in speed, plus slightly varying start times. In any case, there's a very quiet passage, then some piano. Let's examine the second before the first piano note.<p>
Again, we'll start with the LP:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxYX5lfWOxNbgwwzEr4AuUe2MzEang1QSFOP4yUDLBlularddiH73DGPFfQV6QCVC7skPs33KdCWY-8mev-b_TdxTLKNIXW1wuAqxOZAeVTJKiYRfr2OP_dgMOqQExtEGratPQoL20flo/s1090/Screen+Shot+2020-10-06+at+10.46.46+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="575" data-original-width="1090" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxYX5lfWOxNbgwwzEr4AuUe2MzEang1QSFOP4yUDLBlularddiH73DGPFfQV6QCVC7skPs33KdCWY-8mev-b_TdxTLKNIXW1wuAqxOZAeVTJKiYRfr2OP_dgMOqQExtEGratPQoL20flo/s600/Screen+Shot+2020-10-06+at+10.46.46+am.png"/></a></div>
I've simply used the contrast analyser (a power meter) within audacity to show the power in the second before the piano note. -49.36dB is pretty good. Remember this is a media that's full of pops and crackles, and I haven't removed these.<p>
The 1982 CD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQhOZK_IMJm2JlsYOzhk-22okVrDZlq5D1svhbNCUuxMY8Jsw_AGWP6LezXJVUvJC0fYSUrWeRg40Kt8EaqHPZQVOZC2YuXIMWtdILstPnCL9DvHc06-5VJajoh6md0B8ii24e-Jujx_c/s2048/Screen+Shot+2020-10-06+at+10.47.18+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1081" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQhOZK_IMJm2JlsYOzhk-22okVrDZlq5D1svhbNCUuxMY8Jsw_AGWP6LezXJVUvJC0fYSUrWeRg40Kt8EaqHPZQVOZC2YuXIMWtdILstPnCL9DvHc06-5VJajoh6md0B8ii24e-Jujx_c/s600/Screen+Shot+2020-10-06+at+10.47.18+am.png"/></a></div>
Interestingly, significantly noisier than the LP version, at -46.45dB. Nearly 3dB. This is incredibly strange, as one assumes that CD is much quieter than LP. There must be something else at work here. Perhaps the original master tape has degraded somewhat between the LP pressing and the CD mastering?<p>
The 1996 CD:
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicUXBtc1r3pa8nNZy-8Y1r-Q44HHek6gbSmR9wzaWJ6Pjezq9SNf0LGj3HD3heF_UtxpvmWsJPZAbvGSlXYRvbj8mfCYPn5xtcCHm8Q1EMjYJY0EvpquYyiOBOLRZzsE87MWMiCziCgqk/s2048/Screen+Shot+2020-10-06+at+10.47.32+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1026" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicUXBtc1r3pa8nNZy-8Y1r-Q44HHek6gbSmR9wzaWJ6Pjezq9SNf0LGj3HD3heF_UtxpvmWsJPZAbvGSlXYRvbj8mfCYPn5xtcCHm8Q1EMjYJY0EvpquYyiOBOLRZzsE87MWMiCziCgqk/s600/Screen+Shot+2020-10-06+at+10.47.32+am.png"/></a></div>
This result of -43.77dB is pretty much what you'd expect from something that's been compressed. The process boosts the quiet bits. Nice for listening to in the car, not really what you want otherwise.<p>
Finally the SACD. I've gone with the version as recorded, with the slowly increasing gain at the end to fudge a better DR value:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqRYQENzVNRl5FM4Q9FBYU4yptvd5dKfmIEnbxUVogbH1V7I3Lv41Zh4pcvZxN07vcvOgh2nAbLG6rcDVa8Ds-ZXlRjz5Qsu68J4hY373U8wFkI2S5iZAHJAGPShoNgOIldKcxGtUuk5k/s2178/Screen+Shot+2020-10-06+at+10.47.44+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1084" data-original-width="2178" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqRYQENzVNRl5FM4Q9FBYU4yptvd5dKfmIEnbxUVogbH1V7I3Lv41Zh4pcvZxN07vcvOgh2nAbLG6rcDVa8Ds-ZXlRjz5Qsu68J4hY373U8wFkI2S5iZAHJAGPShoNgOIldKcxGtUuk5k/s600/Screen+Shot+2020-10-06+at+10.47.44+am.png"/></a></div>
Now this is interesting. It's -48.01dB, which is good (though not as good as the LP) on the face of it. However when we recognise that this bit of audio is essentially attenuated by something like 1.5dB, in reality it's about the same as the original 1982 CD. This lends some weight to the hypothesis that the SACD is simply the original CD with a slow increase in gain for the last few minutes.<p>
Examining spectrograms of the quiet bit really throws the difference in noise levels among the different versions into sharp relief. First the LP:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0ZqBRwyTjW49qtUnWbB6-am4mz-shAf9pvlwPdC0IS1YR-QeLk4nDjNrf0TpDnknom6Wpim4NDFsDdaHw-oCvadHN87pJ3vQf5SFnwVCqZ-yKRM2cLeq2W3ABwbNrhFGjIXr1h-dOZVc/s1092/Screen+Shot+2020-10-06+at+11.06.35+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="574" data-original-width="1092" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0ZqBRwyTjW49qtUnWbB6-am4mz-shAf9pvlwPdC0IS1YR-QeLk4nDjNrf0TpDnknom6Wpim4NDFsDdaHw-oCvadHN87pJ3vQf5SFnwVCqZ-yKRM2cLeq2W3ABwbNrhFGjIXr1h-dOZVc/s600/Screen+Shot+2020-10-06+at+11.06.35+am.png"/></a></div>
The 1982 CD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9wI4BpCa0_OK37_X9qvVNxg6i4s5q0rA67OPzgFMJtP08aZ1qSb64PDBOfjpXcZFY0yqIQ22dFx9GQbEIq7Z69O8cVZPPtBIkp4Osv4vuJG0yvJq0adT8jhE6XE7scscSGC1bArBeKgM/s2048/Screen+Shot+2020-10-06+at+11.07.33+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1077" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9wI4BpCa0_OK37_X9qvVNxg6i4s5q0rA67OPzgFMJtP08aZ1qSb64PDBOfjpXcZFY0yqIQ22dFx9GQbEIq7Z69O8cVZPPtBIkp4Osv4vuJG0yvJq0adT8jhE6XE7scscSGC1bArBeKgM/s600/Screen+Shot+2020-10-06+at+11.07.33+am.png"/></a></div>
The 1996 CD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx71_Ewyc7Mh9JjtW20IbYKgPni8y1pWUvGYNl7UpFo99XcB7YhKVT6lsZ3uH-LdMklj_xw_Kl77DN9zuzJjKhyphenhyphen_G0uGSqaLwSe38kufNDxvitFwt9zLk8D7t2L22_mJutGZt21k63t7Y/s2048/Screen+Shot+2020-10-06+at+11.09.07+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1082" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx71_Ewyc7Mh9JjtW20IbYKgPni8y1pWUvGYNl7UpFo99XcB7YhKVT6lsZ3uH-LdMklj_xw_Kl77DN9zuzJjKhyphenhyphen_G0uGSqaLwSe38kufNDxvitFwt9zLk8D7t2L22_mJutGZt21k63t7Y/s600/Screen+Shot+2020-10-06+at+11.09.07+am.png"/></a></div>
And the 2014 SACD:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJsF3iV2uhHwjBOnNrJPltXZpnzPkKzAJ2-Dv4jL3zKIZ9oXK1iWCv-NojenZ9Xx4HdWNdFWhLioI72ri8kgQqiFaIe9MPjFY13_WveeuegIvHW7Yd5yxjhIvDn93L3P7o_RxTAuxpynY/s2048/Screen+Shot+2020-10-06+at+11.09.57+am.png" style="display: block; padding: 1em 0; text-align: center; "><img alt="" border="0" width="600" data-original-height="1078" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJsF3iV2uhHwjBOnNrJPltXZpnzPkKzAJ2-Dv4jL3zKIZ9oXK1iWCv-NojenZ9Xx4HdWNdFWhLioI72ri8kgQqiFaIe9MPjFY13_WveeuegIvHW7Yd5yxjhIvDn93L3P7o_RxTAuxpynY/s600/Screen+Shot+2020-10-06+at+11.09.57+am.png"/></a></div>
This is maddening. The LP version is obviously quieter than everything else, in between the pops and clicks! The 1982 CD version and SACD version are really the same thing, and the 1996 CD is garbage. Interestingly the liner notes for the '96 CD version go on about "super bit mapping", a technique using HF dithering to reduce the noise level for the lower frequencies. I'd expect to see an increase in noise towards the high frequencies, but I see no such thing. I'm guessing any dithering improvement is completely masked by the noise level of the source, which simply isn't as quiet as the source used for the LP master.<p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com1tag:blogger.com,1999:blog-924768814112596827.post-9053155961532087942020-08-26T13:52:00.002+08:002020-08-26T13:52:42.849+08:00Making the most of the dyneema - splicing rings for boom attachment points.The 12 strand dyneema SK75 is really nice to work with. Much easier to splice than double-braid, and incredibly strong. I've been using it for all sorts of things on Elena; shrouds, outhaul, and also to fashion attachment points for blocks.<p>
On my boom, I'm attaching the three blocks (two for mainsheet, one for vang) using simple loops. I simply make these by cutting a length of dyneema, then passing the two ends into the rope, while it's attached to the boom. it's extremely simple. With long tapered ends it's very secure under tension, and some lock-stitching (using waxed dyneema thread) holds it neatly while it's not under tension.<p>
Here's a view while working:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1GtglT2KV_a4oA6OTvTEH8ji6Ykn_m21rNxio3jpAeUb3Dj02WlwM1ttISC8lCgnTu_In4-shNOoUyDs89XYkOwnwCwhkAX8HgYXlDjag-8ZVh5dfnThFQhpZFkS8DOvm6kf7QK8Cs9k/s2048/68086E2D-B1B9-4BA5-AD80-AE9E964D5F22.jpeg" style="display: block; padding: 1em 0; text-align: center;"><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1GtglT2KV_a4oA6OTvTEH8ji6Ykn_m21rNxio3jpAeUb3Dj02WlwM1ttISC8lCgnTu_In4-shNOoUyDs89XYkOwnwCwhkAX8HgYXlDjag-8ZVh5dfnThFQhpZFkS8DOvm6kf7QK8Cs9k/s600/68086E2D-B1B9-4BA5-AD80-AE9E964D5F22.jpeg"/></a></div>
And the finished result:<p>
<div class="separator" style="clear: both;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidh9Io2wR0Yx2uQ88SWIOhRrTtLBNNCLKLZNUkfrmFw43cKF0H4rhLYvN7iACqguvRpAyZfz24G7Q6s8KeGC9oKC_Fn8_Xx5C4c_wBtmDSAbVxNYuWOGVHhpC5bGXsF-z-AWl4Kqnz3zY/s2048/A3401A74-32EF-4C8A-97E9-0EC8A598274C.jpeg" style="display: block; padding: 1em 0; text-align: center;"><img alt="" border="0" width="600" data-original-height="1536" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidh9Io2wR0Yx2uQ88SWIOhRrTtLBNNCLKLZNUkfrmFw43cKF0H4rhLYvN7iACqguvRpAyZfz24G7Q6s8KeGC9oKC_Fn8_Xx5C4c_wBtmDSAbVxNYuWOGVHhpC5bGXsF-z-AWl4Kqnz3zY/s600/A3401A74-32EF-4C8A-97E9-0EC8A598274C.jpeg"/></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com1tag:blogger.com,1999:blog-924768814112596827.post-81196565707346524192020-07-12T10:21:00.002+08:002020-07-12T10:21:48.379+08:00Just a quick pic of my duc<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMfxT2hlJmRFxKnU2fULTTrsziVxOnaGXbq6RwjrbFjaApMuGJeHG_SfusEdMZZIXO7y4fbsfeslrdEm2fRTb2MvJh_zTerLckLjGv0ayt1N2KMm7ZN048FpPs8bPDHF7rC0pxWlttLUU/s1600/D3ABA97E-B9DE-469A-B4C9-8136F717D570.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMfxT2hlJmRFxKnU2fULTTrsziVxOnaGXbq6RwjrbFjaApMuGJeHG_SfusEdMZZIXO7y4fbsfeslrdEm2fRTb2MvJh_zTerLckLjGv0ayt1N2KMm7ZN048FpPs8bPDHF7rC0pxWlttLUU/s640/D3ABA97E-B9DE-469A-B4C9-8136F717D570.jpeg" width="640" height="480" data-original-width="1280" data-original-height="960" /></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-7425426994529671682020-05-26T15:23:00.000+08:002020-05-26T15:23:00.956+08:00RudderWelsford’s plan for the Navigator shows a rudder with an up-haul and a down-haul. I’m not too keen on the idea of down-hauls, as if I hit things and the down-haul doesn’t release, then bad things happen.<p>
So I figured I’d omit the down-haul, and instead weight the rudder with lead, similarly to the centerboard. Hey, every little bit of tighting moment has to help some, right.<p>
This time with the lead, I just went and bought a pile of lead flashing. I melted it in an old cast iron pan outside, and poured it into a mold made from steel and aluminium.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg954LQcEIQ62QvpHCinRiJ1cCN4LRKMhx14nEtqHR8_Hqv4DnbXTfzOVErxC2wwKGUOh38vGx0EgSBVuv5V2mI3OSGuMfN8hVi65LBplQ1kbaeZRds42GxKyJB-0FSpLZTBs8IlPubw7Q/s1600/F09EF144-551D-4F60-8C6C-4EDC5A20F997.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg954LQcEIQ62QvpHCinRiJ1cCN4LRKMhx14nEtqHR8_Hqv4DnbXTfzOVErxC2wwKGUOh38vGx0EgSBVuv5V2mI3OSGuMfN8hVi65LBplQ1kbaeZRds42GxKyJB-0FSpLZTBs8IlPubw7Q/s640/F09EF144-551D-4F60-8C6C-4EDC5A20F997.jpeg" width="640" height="480" data-original-width="1600" data-original-height="1200" /></a></div>
I cut that into the rudder core, made from four 12mm thick jarrah planks.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFk83z82cnx6ienYM5-eN5WD9aa2bYBAJ_wCXCPQPTz79Dyqnrq6WETamWNgMlKhnwuoOXyZn45UuZJWK9U5dwM98QjGDGpJK_Xm5bj1ru2frVmpBtd82j5hMZHasuesCV-febo4d_jJ0/s1600/5088838F-9914-4A43-A097-BD849B13A73A.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFk83z82cnx6ienYM5-eN5WD9aa2bYBAJ_wCXCPQPTz79Dyqnrq6WETamWNgMlKhnwuoOXyZn45UuZJWK9U5dwM98QjGDGpJK_Xm5bj1ru2frVmpBtd82j5hMZHasuesCV-febo4d_jJ0/s640/5088838F-9914-4A43-A097-BD849B13A73A.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
And then glued on cheeks made from Tassie Oak, roughing it to shape with the bandsaw, power plane, and jack plane, then 40 grit in the sander.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil_tft6RJfgGb82splPE7YiJSdMb1bS6MIPJGOq88iEJLpD2VHPsJ44mS7zvTEGrh8r0HMo6KjBjw0eg35fy9H_g178hyZ3nv76DolPOD9mMzmpUJIkzXrtGTucxz07e_PuggEVkE1vt8/s1600/D56925A0-652D-4BA2-A0A2-6EFED9623842.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEil_tft6RJfgGb82splPE7YiJSdMb1bS6MIPJGOq88iEJLpD2VHPsJ44mS7zvTEGrh8r0HMo6KjBjw0eg35fy9H_g178hyZ3nv76DolPOD9mMzmpUJIkzXrtGTucxz07e_PuggEVkE1vt8/s640/D56925A0-652D-4BA2-A0A2-6EFED9623842.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpJNrb2lyvmLoYx-hZF8JKceG0woldTsSEettU_bc1JdaK-q4_DTiLHkLtoMbyWpJ0aW2nejjqnt-AX0A2pBSMIYLpLQpCKaLJzGG8yPUxkgUNc8V2ZMKSb5MI32eRHn9xBd7Jty5m0Os/s1600/76717E8D-4012-4427-BFAA-40BEAA11FA45.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpJNrb2lyvmLoYx-hZF8JKceG0woldTsSEettU_bc1JdaK-q4_DTiLHkLtoMbyWpJ0aW2nejjqnt-AX0A2pBSMIYLpLQpCKaLJzGG8yPUxkgUNc8V2ZMKSb5MI32eRHn9xBd7Jty5m0Os/s640/76717E8D-4012-4427-BFAA-40BEAA11FA45.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
I’ve added a pivot point (16mm hole with 12.7mm bronze bushes), and an eye for the up-haul, which I think will have to be 2:1 on account of the weight.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwYEVy1p4PA2YP8MsnbgxTk48998kHjNceerJnovKnLqOuW4Em1RyJuVkm7K-VkGIuasssjM3MRH00PLx3jnPnr0UrCnTOaU0aeqWUFsCSWPuZTRD3KsF_TNu4BeeFRRfPxblWYwm9-zs/s1600/860C5D53-BBDD-439E-8C28-03A18119E4D9.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwYEVy1p4PA2YP8MsnbgxTk48998kHjNceerJnovKnLqOuW4Em1RyJuVkm7K-VkGIuasssjM3MRH00PLx3jnPnr0UrCnTOaU0aeqWUFsCSWPuZTRD3KsF_TNu4BeeFRRfPxblWYwm9-zs/s640/860C5D53-BBDD-439E-8C28-03A18119E4D9.jpeg" width="640" height="480" data-original-width="1280" data-original-height="959" /></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com3tag:blogger.com,1999:blog-924768814112596827.post-59997060176267507342020-05-05T08:32:00.000+08:002020-05-06T13:17:20.474+08:00I can stop any timeA picture of my frypan collection.<p>
They’re all Le Creuset, mostly vintage. Two of them have had the enamel stripped and replaced with seasoning.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrfXith6-T_JeBFG-Pab_VLaBtoqNO5pCUR2e-GDQ0u8AWrRpLPsmjl7v6p8784ZjHxlukFsqkkOmZZMBU5qdv9YnlhkAnBIzYuE5kYkLIwLwC19vNMRouC0YK0IOcoGt8XRW6YnF5U3I/s1600/A2E4BDE1-55D3-4DC1-8CDD-EBE1FBF22900.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrfXith6-T_JeBFG-Pab_VLaBtoqNO5pCUR2e-GDQ0u8AWrRpLPsmjl7v6p8784ZjHxlukFsqkkOmZZMBU5qdv9YnlhkAnBIzYuE5kYkLIwLwC19vNMRouC0YK0IOcoGt8XRW6YnF5U3I/s640/A2E4BDE1-55D3-4DC1-8CDD-EBE1FBF22900.jpeg" width="640" height="480" data-original-width="1280" data-original-height="960" /></a></div>
And the omelette process. We start with my favourite pan, a 23cm Le Creuset with the enamel stripped, seasoned with lard. When the seasoning is just so it’s a little glossy.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheZQFp_U8cqemv8b6_vNQqgNvKWjZ2dYwct-H9m9iU8iyWhRXm4ic_kCbgDVKrR_0A9PcDY6diWZEdJ90TmP1ky94UaeLmBi0Mm9XvnFIdg3spiTcYHcQH8x-oPPQ7q6dX1yhnZJnugzI/s1600/41357699-98EF-4C79-9B0F-9ABF847799F8.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheZQFp_U8cqemv8b6_vNQqgNvKWjZ2dYwct-H9m9iU8iyWhRXm4ic_kCbgDVKrR_0A9PcDY6diWZEdJ90TmP1ky94UaeLmBi0Mm9XvnFIdg3spiTcYHcQH8x-oPPQ7q6dX1yhnZJnugzI/s640/41357699-98EF-4C79-9B0F-9ABF847799F8.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Ingredients for a basic omelette are a bit of butter, two eggs, some finely cut spring onion and a little grated cheddar cheese, with salt and pepper.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin9HeffoMSAGxTiMJ3USvBH_ifnmUF8yJ16fh_a6fkgVAhdUz3yquUT43G_-qhcjZoPMesSxypEaPb-fGzu9MM1NHj378kgAcZ48viF2Ck2SLDF9jQe7Xs0PUZNVJPKqATKiMXpQlA3mk/s1600/6EF40A28-153D-4446-B77D-35610FA4DC27.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin9HeffoMSAGxTiMJ3USvBH_ifnmUF8yJ16fh_a6fkgVAhdUz3yquUT43G_-qhcjZoPMesSxypEaPb-fGzu9MM1NHj378kgAcZ48viF2Ck2SLDF9jQe7Xs0PUZNVJPKqATKiMXpQlA3mk/s640/6EF40A28-153D-4446-B77D-35610FA4DC27.jpeg" width="640" height="480" data-original-width="1600" data-original-height="1200" /></a></div>
Chuck the butter in the pan and heat it until it’s foaming. While that happens go at the eggs lightly with a fork, and add salt and pepper.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheiEoqJlQOOqkJVhJeWHWKCiudZcmzm_glCnONqjF1T1qtLmbaAudSvL66SNxnh629BCCmgm01p3NpzaE56VYlyCN2Ofmt46V6orIN0rjMl-J_S1P1lwT9CxIQPenzLnWgeNESnaCVMLQ/s1600/5D854143-B9F2-49C9-A490-8E75F0354DD4.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheiEoqJlQOOqkJVhJeWHWKCiudZcmzm_glCnONqjF1T1qtLmbaAudSvL66SNxnh629BCCmgm01p3NpzaE56VYlyCN2Ofmt46V6orIN0rjMl-J_S1P1lwT9CxIQPenzLnWgeNESnaCVMLQ/s640/5D854143-B9F2-49C9-A490-8E75F0354DD4.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Add the eggs to the pan when the butter quietens down. Then chuck the spring onion on top. Move it around a little with a fork to get the folds, and allow the runny egg to run onto the bare pan.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz8g1GHm9g9eYCyY3cul__DTi1IreeG2DCHACgwf-BrNKs-l0djXnRP-oXy218K-gfZyM0lRYsTqBFbvYp0IS8yig2uiI7YIO18Cabi8g0eCntsaCnL7kehFKATv-9lyJKAdqZ_GbUD9M/s1600/5904EE81-F88D-4828-9C29-3678415ECA1E.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz8g1GHm9g9eYCyY3cul__DTi1IreeG2DCHACgwf-BrNKs-l0djXnRP-oXy218K-gfZyM0lRYsTqBFbvYp0IS8yig2uiI7YIO18Cabi8g0eCntsaCnL7kehFKATv-9lyJKAdqZ_GbUD9M/s640/5904EE81-F88D-4828-9C29-3678415ECA1E.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
I like to add a teensy bit of grated cheese, which I melt with a torch. I used to pop it under the grill for a few seconds, but the torch is much more controllable.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrl4m_seP_33OsCc7He2D5plKPOnf3dP0O5eOEmYahqvq3WlrwzIaNTaJbz8tnEqbkLRqv5h3DQROUo_o3Lxehfp7HPdbZOSqtOgUUwBZbzpeCSetrPzfKUgtEjo89NpVpPahyphenhyphenEYSYnos/s1600/27C0D7BC-968C-423F-8C9D-4191230AA9E3.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrl4m_seP_33OsCc7He2D5plKPOnf3dP0O5eOEmYahqvq3WlrwzIaNTaJbz8tnEqbkLRqv5h3DQROUo_o3Lxehfp7HPdbZOSqtOgUUwBZbzpeCSetrPzfKUgtEjo89NpVpPahyphenhyphenEYSYnos/s640/27C0D7BC-968C-423F-8C9D-4191230AA9E3.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Finally fold it in half with a fork, and slide it onto a plate.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYc8J2hbFIlWKV8SuiEpk0HWbrUw0PqQlx_LwCq7zzHGCKpRLuaDDP9XJ0xH_mGc5AAPDJS8dTwccEiGGk6WLuTIfDZ2xgVxovaeL2rPxz1WcujJgF-JWZtyH-g7RDtOVCiRKgGEHHS2Y/s1600/26330781-2A9E-4C65-A631-D01AAEBD07C5.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYc8J2hbFIlWKV8SuiEpk0HWbrUw0PqQlx_LwCq7zzHGCKpRLuaDDP9XJ0xH_mGc5AAPDJS8dTwccEiGGk6WLuTIfDZ2xgVxovaeL2rPxz1WcujJgF-JWZtyH-g7RDtOVCiRKgGEHHS2Y/s640/26330781-2A9E-4C65-A631-D01AAEBD07C5.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKoPeQcshssrZ53DCJPmaWCR1KGMz2M34KxgGwZt5tGwqEtuleeWOdsuYoX8yGse5HcybJPCP0NvyTwVvn65WXLFhs3uyYO0APtKLL08Jp8ZvUOlRgrNTAWWO2uPBlWrxbErau-EGk-p0/s1600/CE7308F7-1851-429E-AE99-FDE2361A7F3D.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKoPeQcshssrZ53DCJPmaWCR1KGMz2M34KxgGwZt5tGwqEtuleeWOdsuYoX8yGse5HcybJPCP0NvyTwVvn65WXLFhs3uyYO0APtKLL08Jp8ZvUOlRgrNTAWWO2uPBlWrxbErau-EGk-p0/s640/CE7308F7-1851-429E-AE99-FDE2361A7F3D.jpeg" width="640" height="480" data-original-width="1280" data-original-height="960" /></a></div>
Et voila. Bon apetite!<p>
Sometimes I just chuck in whatever’s in the fridge. Pepperoni, chorizo, cherry tomatoes, mushroom, etc. But that usually ends in a thicker omelette that won’t fold.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioGFB_jL0Dsv1cg7EG5xLHswE8am-6GuJJktE562n6kGr-IR4WKigpaqUkPHSRRS2MLV-cb0ou3tw0cbi_-0MOUUqhUduOWb9wWWPdbWStx7DN-b52PrV9zkfNGOF-HxChoiEw0SxvO0I/s1600/808E19C5-55CF-46F5-B4C7-6A948AC5D0ED.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioGFB_jL0Dsv1cg7EG5xLHswE8am-6GuJJktE562n6kGr-IR4WKigpaqUkPHSRRS2MLV-cb0ou3tw0cbi_-0MOUUqhUduOWb9wWWPdbWStx7DN-b52PrV9zkfNGOF-HxChoiEw0SxvO0I/s640/808E19C5-55CF-46F5-B4C7-6A948AC5D0ED.jpeg" width="640" height="480" data-original-width="1280" data-original-height="960" /></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-50132507051916559182020-05-03T08:56:00.000+08:002020-05-03T08:56:09.145+08:00Doodles towards a new boatSo these are the constraints I'm working to:<p>
<ul>
<li>Beam of around 2300mm, to allow the boat to be stored behind my house (the gap between the fence and my garage is 2400mm). This will also allow for trailering without wide load placards, being under 2400mm.</li>
<li>Length of around 6000-6500mm. This is a bit more vague, as there's no specific constraint here, but the 6m length tends towards a 2300mm beam, so this is it.</li>
<li>Maximum draft of around 800mm. More than this makes trailer launching at boat ramps really hard. Indeed even launching a boat with an 800mm draft will be hard. Stability and cabin room is however directly related to draft, so there is a strong push to maximise draft at the expense of trailerability.</li>
<li>Maximum weight of around 1800kg unladen. The tow vehicle I am considering has a maximum towing weight of 2500kg. If we subtract 700kg for trailer, we end up with 1800kg for the boat. Stability constraints again push us upwards here, and trailerability constraints push us down. I think something around 1400-1500kg is probably reasonable. This implies a displacement of around 2000kg.</li>
<li>As much sailing ability as I can get given those other constraints. Ideally I want something I can sail across the Great Australian Bight in, so some measure of blue water capability.</li>
</ul>
Some of these constraints are directly contradictory. Trailerability comes at the direct expense of blue water ability. I think I can find a happy compromise that ends up in a boat that's enough different to Elena to make the exercise worthwhile.<p>
I'm working on the premise of a 6m LOD, 2.3m beam, 0.6-0.8m draft boat with centerboard mounted in a trunk below the cabin floor. Katie comes pretty close, but the draft is perhaps a little on the shallow side, at around 0.48m board up. Pretty-much everything that's designed without a board has a draft of over 0.9m, which I think is just a little deep.<p>
To find a better compromise, I thought I might try developing my own hull shape. I started with the table of offsets for Buzzard's Bay by Herreshoff, as published in Sensible Cruising Designs. I found the table of offsets to be surprisingly lumpy, so abandoned any attempt to stick to the table of offsets and instead just started drafting lines in Sketchup. The process was first to draw a profile (face), and overall plan view, to constrain LOD, beam and draft. The shape is similar to Buzzard's bay but I brought the bow up more vertically above the waterline, and increased the radius of the turn of the bilge, giving the rabbet a hard inflection rather than a smooth curve.<p>
Then I drew waterlines and stations, got them to line up, drew buttocks, found they were miles off fair, edited the waterlines, edited the stations, edited the buttocks, and went around the loop half a dozen times, until the waterlines, buttocks and stations all intersect with errors of <1mm or so. I think the shape is reasonably pleasing.<p>
Here's the profile:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6DPJuywgGOdo3WDg4DnSqLY1DrrsCFPxoPBjgmHm6kVmxQfOHnMKcNsoWkUtgzOi-7H-RCZVw26x3KUmCs0tGYp1l1YL0dEF1sJVb7DCt8_bEA8jUiKLLDSgm_A9G51AQWcN50TVaRBM/s1600/Screen+Shot+2020-05-03+at+6.56.38+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6DPJuywgGOdo3WDg4DnSqLY1DrrsCFPxoPBjgmHm6kVmxQfOHnMKcNsoWkUtgzOi-7H-RCZVw26x3KUmCs0tGYp1l1YL0dEF1sJVb7DCt8_bEA8jUiKLLDSgm_A9G51AQWcN50TVaRBM/s640/Screen+Shot+2020-05-03+at+6.56.38+am.png" width="640" height="221" data-original-width="1600" data-original-height="553" /></a></div>
Draft ended up 760mm, which is just shy of my maximum of 800mm. LOD is 6380mm. Beam is 2300mm. There is 750mm freeboard at the bow, dropping to 470mm amidships and raising again to 600mm at the transom.<p>
The plan view is below:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz-4g2uvmbckMFmfR1BjYqBjtxOqvMpbLbE1ayGe2sjYdbVxA5nqN9y1rNDN65l07ilSkrtrU4s5CIVvFCcbFbkm1A84N7End2TjPJmhP22T6pcrvAwXaTSxAT3s-yYe-xERWSO2gHSgA/s1600/Screen+Shot+2020-05-03+at+6.56.14+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz-4g2uvmbckMFmfR1BjYqBjtxOqvMpbLbE1ayGe2sjYdbVxA5nqN9y1rNDN65l07ilSkrtrU4s5CIVvFCcbFbkm1A84N7End2TjPJmhP22T6pcrvAwXaTSxAT3s-yYe-xERWSO2gHSgA/s640/Screen+Shot+2020-05-03+at+6.56.14+am.png" width="640" height="289" data-original-width="1600" data-original-height="723" /></a></div>
After the issues I had with Elena getting the garboard plank around to the bow with a strong concave section, I kept the bow mostly convex, even down at the garboard. There is s reasonably strong turn to the bilge at the stern. This gives a nice shape to the transom and I think will also provide additional stability.<p>
The rear view is also shown:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigDaYpT56aOmv6nVRPSQ_I-xG4chlsTuKNIriYCIoW_eMHWDigu2jroBRWFPmJH5h6bHbZB-R_NmJSh9yShuqJoB-2P3sKYW7rCcichzFHvry3y2sM9HOKSlzji-eVlyec1KS3vDH5Gfw/s1600/Screen+Shot+2020-05-03+at+6.57.07+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEigDaYpT56aOmv6nVRPSQ_I-xG4chlsTuKNIriYCIoW_eMHWDigu2jroBRWFPmJH5h6bHbZB-R_NmJSh9yShuqJoB-2P3sKYW7rCcichzFHvry3y2sM9HOKSlzji-eVlyec1KS3vDH5Gfw/s640/Screen+Shot+2020-05-03+at+6.57.07+am.png" width="640" height="465" data-original-width="1600" data-original-height="1162" /></a></div>
I haven't put any tumblehome in to the stations. I'm wondering if perhaps bringing the gunwales in a tad might make for more strength to the form, but also want a decent amount of room on deck to be able to get past the cabin, when I design one in. I may change things around a bit as I keep going.<p>
Finally the quarter-view. I haven't sheeted the hull in sketchup, so it's just a bunch of lines.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQkGETFamBAtjwTm6kAn67zoHxVsFVx1KdnnJVzCshf5w-knfIa6VLqJgXXW5Ymw1rLdHiCl_FbxAQ8PRa8q_gBFExBQPb5nruvmQyk9u3O7EMMEjrfw_YSVj4NrMfmUA8BrbGB8n9LoY/s1600/Screen+Shot+2020-05-03+at+6.57.43+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQkGETFamBAtjwTm6kAn67zoHxVsFVx1KdnnJVzCshf5w-knfIa6VLqJgXXW5Ymw1rLdHiCl_FbxAQ8PRa8q_gBFExBQPb5nruvmQyk9u3O7EMMEjrfw_YSVj4NrMfmUA8BrbGB8n9LoY/s640/Screen+Shot+2020-05-03+at+6.57.43+am.png" width="640" height="516" data-original-width="1600" data-original-height="1290" /></a></div>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-83569719889461806402020-04-24T17:33:00.001+08:002020-04-24T18:02:05.727+08:00More riggingMuch of the rigging for the mast is done now. I have a vang, mainsheet and outhaul. The virus has made a real mess of things. I’m waiting on rudder fittings, boom end fittings and more cleats. From the sound of it I might not be getting those for months.<p>
So today I assembled everything I have for a test-fit. It took us about half an hour in the driveway to put it all together. First views from the side, aft, and forward:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIr8c9VYH9hnIpxo98DK1S6iv84R_Qpz3SpbfbmUqralSBaAtWCeYxU4Yt7cIUh7CVdmnp2SB0Q_sEQOJlylRLlLS5t4x6ZZzGMf0_-ZnR_2CJYJ9aMP5q8Qj3f8ZGDtFSn0HfAIbZMj4/s1600/20BF5391-B605-44B8-AAD3-6355F1133EAD.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIr8c9VYH9hnIpxo98DK1S6iv84R_Qpz3SpbfbmUqralSBaAtWCeYxU4Yt7cIUh7CVdmnp2SB0Q_sEQOJlylRLlLS5t4x6ZZzGMf0_-ZnR_2CJYJ9aMP5q8Qj3f8ZGDtFSn0HfAIbZMj4/s640/20BF5391-B605-44B8-AAD3-6355F1133EAD.jpeg" width="417" height="640" data-original-width="833" data-original-height="1280" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Nk6bDApqX_STNje95sO42gspMIvT2dbEES6eWQI-a6MkW0G4GQkdDIu0eXsg4PiCBH5WOEHazpg12bPysuapXUoqDkTC_tuSWbRoUJhUnFBdcFBO5IOahGIPCK2JAkzn9Xn2U3qDurY/s1600/28B89152-DFB5-45A2-9DF5-72CA3ABFFA06.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9Nk6bDApqX_STNje95sO42gspMIvT2dbEES6eWQI-a6MkW0G4GQkdDIu0eXsg4PiCBH5WOEHazpg12bPysuapXUoqDkTC_tuSWbRoUJhUnFBdcFBO5IOahGIPCK2JAkzn9Xn2U3qDurY/s640/28B89152-DFB5-45A2-9DF5-72CA3ABFFA06.jpeg" width="480" height="640" data-original-width="960" data-original-height="1280" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkBxcGllvckiT2IM53FDusTCj0KPB73TsRP7oz-UONLa0y0q6w8Jla29ZvRHRcL_UnDH_BYfyrkkTzqRFtcijCwjzuRL0npsseiTh0riPkhS-p6wBtt8IrfPz00peYAFlv9YbZzNBg1n0/s1600/82EF57DF-9469-4E23-97F9-3262522D137B.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkBxcGllvckiT2IM53FDusTCj0KPB73TsRP7oz-UONLa0y0q6w8Jla29ZvRHRcL_UnDH_BYfyrkkTzqRFtcijCwjzuRL0npsseiTh0riPkhS-p6wBtt8IrfPz00peYAFlv9YbZzNBg1n0/s640/82EF57DF-9469-4E23-97F9-3262522D137B.jpeg" width="456" height="640" data-original-width="911" data-original-height="1280" /></a></div>
A closer view of the bowsprit arrangement, with cleats added for tensioning the bobstay and forestay:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpVMIlHMhq1lWd-Kxp2PfdGlMCy0k9d_m0xPdYjKrkM5WVcg403Klm_kVHiUrL8gErxurpw3NvEQcICZBH5CwDzUhSz7YqbubtWSbyRtK5m_efuQbCuqX8JI5t9M5WlEf0D7u0segB1pw/s1600/CE19B62F-9B8C-488D-B8CD-2D6DD3158330.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpVMIlHMhq1lWd-Kxp2PfdGlMCy0k9d_m0xPdYjKrkM5WVcg403Klm_kVHiUrL8gErxurpw3NvEQcICZBH5CwDzUhSz7YqbubtWSbyRtK5m_efuQbCuqX8JI5t9M5WlEf0D7u0segB1pw/s640/CE19B62F-9B8C-488D-B8CD-2D6DD3158330.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Here’s the vang. I did it as a 4:1 using a 40mm fiddle block with becket and cleat at the mast end, and a 40mm fiddle block at the boom. I wrapped a dyneema line around the mast to secure the bottom. At the top it’s got a loop of 6mm double-braid through a hole in the boom.<p>
You can also see the missing bronze fitting that’s supposed to go on my boom, plus a bunch of cleats. At the bottom is my 3:1 centerboard lifting line, using a 29mm double block and a sheave with becket in the board.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4uUFk3IzAbMqrclBC7LeIangvfpbPhN1SzSpZDB2WVNiqGp2Gh3AJkMY_fr6Tq3gdsMp9aiaP2ld6a3QD3ldhLd65Qr_st587m6bh0cinyOfkbL1zyDK_ywGXDW7kdtCUZUXOjOjWcd8/s1600/A8AD1CB7-7FC1-4F9F-8499-41E40F5293A2.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4uUFk3IzAbMqrclBC7LeIangvfpbPhN1SzSpZDB2WVNiqGp2Gh3AJkMY_fr6Tq3gdsMp9aiaP2ld6a3QD3ldhLd65Qr_st587m6bh0cinyOfkbL1zyDK_ywGXDW7kdtCUZUXOjOjWcd8/s640/A8AD1CB7-7FC1-4F9F-8499-41E40F5293A2.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Here’s a pic showing a dinky little 22mm block that runs inside the boom to give me a 2;1 outhaul:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7GJyfUancgNtqMkTAL4h_t3_sCbD0piS4KL-TVsub-JO17pWY6Zvi56jmxOJY_siFmFJFz7jvcIVyb3ga61v2F_7q-DnoVKwm_4j04sFLWryhOkqOzBZAKRoi2RLY2h7vzpoxm2h5T7c/s1600/B4020071-E775-44E1-BE45-D555DEC16975.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7GJyfUancgNtqMkTAL4h_t3_sCbD0piS4KL-TVsub-JO17pWY6Zvi56jmxOJY_siFmFJFz7jvcIVyb3ga61v2F_7q-DnoVKwm_4j04sFLWryhOkqOzBZAKRoi2RLY2h7vzpoxm2h5T7c/s640/B4020071-E775-44E1-BE45-D555DEC16975.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
Here’s my mainsheet. I’m using 8mm double-braid, in a 3.5:1 system, using a 40mm block with becket on the bridle, running to a double 40mm block at the end of the mast, then a 40mm block mid-way along the mast runs the line down to a 55mm high-zoot factor ratchet block at the back of the centerboard case, which I hold down with a dyneema soft shackle.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgC65Tm6NieV17QdoWhyphenhyphen-5wz-5f7-TZPMHS8NsO68pd-4bVZHvIM4pq3v2zi_edSUu3SQ7FFip_D426zkJ-8y0jfRCgf3hPxYYCpMFP5OUiGmX22xsizOHl0xzRHQAmOwpOilbNVumWVo/s1600/4A04E9FC-6187-496B-BEB7-1AB363D19FA8.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgC65Tm6NieV17QdoWhyphenhyphen-5wz-5f7-TZPMHS8NsO68pd-4bVZHvIM4pq3v2zi_edSUu3SQ7FFip_D426zkJ-8y0jfRCgf3hPxYYCpMFP5OUiGmX22xsizOHl0xzRHQAmOwpOilbNVumWVo/s640/4A04E9FC-6187-496B-BEB7-1AB363D19FA8.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBaXHA-EywBhgSJPoKCPgiznRt4An23B2tAI-1ovolZKkVRf2fLSQ2KxvW8thVN0Sk0UxgdL5MHha_4g7MOMy8cwpmzBFR408OSdZITQ_LKWDweqDToj1kxw4UKGfnVx9IDWAC6uoxhHg/s1600/F616CC61-DC00-4B18-AF3F-10E0D86E0F46.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBaXHA-EywBhgSJPoKCPgiznRt4An23B2tAI-1ovolZKkVRf2fLSQ2KxvW8thVN0Sk0UxgdL5MHha_4g7MOMy8cwpmzBFR408OSdZITQ_LKWDweqDToj1kxw4UKGfnVx9IDWAC6uoxhHg/s640/F616CC61-DC00-4B18-AF3F-10E0D86E0F46.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
I’m holding off until I get the sails before I install the jib sheet blocks, so I can locate them just so.<p>
Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-20618164387982367032020-04-19T07:06:00.001+08:002020-04-19T07:33:40.762+08:00Meet KatieSo I made a decision in record time and have ordered plans for <a href="https://www.harrybryan.com/products/katie">Katie, by Harry Bryan.</a><p>
There's a lovely video tour of Katie available at <a href="https://www.offcenterharbor.com/videos/tour-aboard-katie-harry-bryans-gaff-sloop/?prev=yes">Off Center Harbour.</a><p>
Katie is a good compromise between draft and stability. She makes use of a lead keel plus a centerboard. My only reservations with Katie is that the cabin is a tad small (Harry designed her to have a big cockpit instead) and I can tolerate a bit more draft than she has in order to improve stability.
So some quick doodling on the picture of the plans that I have to illustrate my changed:<p>
Firstly I scaled her vertically by 105%. This small change adds about 25mm of draft (from 480mm to 505mm) and 25mm of freeboard. It also gives me an extra 50mm of headroom in the cabin.<p>
Then I add ballast to bring her waterline up by 25mm. That resets the freeboard to 480mm, and now my draft is 530mm.<p>
My keel extension will add about 50mm on the bottom of the boat, giving me a total draft of around 580mm. I reckon this is still trailerable. It's certainly a lot less than the 900-1200mm draft of other designs I've been looking at.<p>
Harry mentions that Katie originally suffered from mild weather helm. He cured that in the original by adding keel at the rudder end. I propose extending the centerboard back by around 250mm to deal with this. Additionally because of the taller keel we're able to drop the centerboard down a tad so most of the centerboard case inside the cabin is at floor height.<p>
Finally we simply extend the cabin by moving it's bulkhead back around 500mm.<p>
The results of my doodles is shown below:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcqx3QCAUdxgDrEaPaTv8eJMWkaFXovnsFiyU4bQ9FpbcHsedSiLDFEiOjQOwMHKwiJ5-08q8IREugWXa7O94aoii9Z2R9JJaLZuE_Y4Ams2ASWXzjY525TBrtpmtChOzJ69goxLRnLmU/s1600/Screen+Shot+2020-04-19+at+6.39.01+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcqx3QCAUdxgDrEaPaTv8eJMWkaFXovnsFiyU4bQ9FpbcHsedSiLDFEiOjQOwMHKwiJ5-08q8IREugWXa7O94aoii9Z2R9JJaLZuE_Y4Ams2ASWXzjY525TBrtpmtChOzJ69goxLRnLmU/s640/Screen+Shot+2020-04-19+at+6.39.01+am.png" width="640" height="378" data-original-width="1600" data-original-height="944" /></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-43040957885504837932020-04-17T10:37:00.000+08:002020-04-17T10:37:13.601+08:00The dawning realisation of life without a boat to build.One of the truly shocking realisatons of late is that shortly Elena will be built, and then I won't have a boat to build any more.<p>
That's utterly unacceptable.<p>
I'm thinking now of starting on a small "pocket cruiser". Something that I can pull out of the water and keep in the back yard under the pergola when I'm not cruising in it, but still with enough size, weight, and cabin to really go places.<p>
Also I'm fed up with plywood, so I want to make a boat from cut timber. Clinker is the romantic ideal, but strip built is probably going to be a lot more amenable to keeping out of the water for extended periods, so I don't completely get away from epoxy.<p>
I asked for ideas on the woodenboat forum, and have been inundated with suggestions. Seems a lot of people have been thinking along these very same lines.<p>
Here's a spreadsheet tabulating most of them.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-KN2Ol4tiNJS3PkM9v_IawL2k8qX8xsajGipoDGcTZcDntqO_L9pOKRKC41uekAfliQWG6VcPe3gVobVg4KCyayLD8p09wA0_rPtHfeAbgVXidhRLp-b-JJeOpsqM0EnhooBWzNCEnoM/s1600/Screen+Shot+2020-04-17+at+10.31.24+am.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-KN2Ol4tiNJS3PkM9v_IawL2k8qX8xsajGipoDGcTZcDntqO_L9pOKRKC41uekAfliQWG6VcPe3gVobVg4KCyayLD8p09wA0_rPtHfeAbgVXidhRLp-b-JJeOpsqM0EnhooBWzNCEnoM/s640/Screen+Shot+2020-04-17+at+10.31.24+am.png" width="640" height="368" data-original-width="1600" data-original-height="919" /></a></div>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0tag:blogger.com,1999:blog-924768814112596827.post-70573881025363365032020-04-13T14:25:00.002+08:002020-04-17T13:52:02.378+08:00Shroud attachment detailsBeing stuck in the house, and being almost out of epoxy, I’m working on odds and sods. One of these is the shroud attachment. My copy of “Sensible Cruising Designs” by Herreshoff, shows a short cut for attaching shrouds using two plates and a clevis pin, rather than a shackle. Ditching the shackle eliminates a potential rattle, so it sounds good to me.<p>
So this is what that looks like for Elena:<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhufAtCFJVnv9soAsEWBmf9MP6A4rjat-nNDHG6MVonfGlXVGBNerTY23A2QvRKWIT7IyyYNbQqSZlZhIhq2eO22wXHQEloQyP_WXYABtwYXg461E8UhEwIbvQ9D5p3VAlqPj5BDEZNwIU/s1600/CAFDEC37-9BFF-4E56-A88E-3C914E42BEBD.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhufAtCFJVnv9soAsEWBmf9MP6A4rjat-nNDHG6MVonfGlXVGBNerTY23A2QvRKWIT7IyyYNbQqSZlZhIhq2eO22wXHQEloQyP_WXYABtwYXg461E8UhEwIbvQ9D5p3VAlqPj5BDEZNwIU/s640/CAFDEC37-9BFF-4E56-A88E-3C914E42BEBD.jpeg" width="640" height="479" data-original-width="1280" data-original-height="958" /></a></div>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg659UzlVWuZoDojsNWxOXd7Hdyn1Bz06PLf2156OiatGt-TFqY2cM6KYkKWUAahVRerh8sfT8Yydr6Ev0rsqyR1Tpx7BVlEaihlbnwrXkoj1tNmCvKFhBZdn_egi98lxcYtfgZyyAuugM/s1600/E430C661-16AF-4C07-87FB-3E4E351A3570.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg659UzlVWuZoDojsNWxOXd7Hdyn1Bz06PLf2156OiatGt-TFqY2cM6KYkKWUAahVRerh8sfT8Yydr6Ev0rsqyR1Tpx7BVlEaihlbnwrXkoj1tNmCvKFhBZdn_egi98lxcYtfgZyyAuugM/s640/E430C661-16AF-4C07-87FB-3E4E351A3570.jpeg" width="640" height="480" data-original-width="1280" data-original-height="960" /></a></div>
I’m not super happy with the forestay attachment. I had a lot if difficulty bending the bronze strap neatly, and it shows. It’s not a particularly good fit, either.<p>
I’m wondering if perhaps a cooler way to do this might be a loop of Dyneema rather than bronze.<p>
Edit: I made a 20cm bridle from 5mm dyneema. This is the shortest I could do maintaining 20:1 bury in the brummel lock splices. The eyes go over some 12mm dia bronze tubes, which sit under the shroud attachments. I reckon this is much nicer.<p>
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgK45Zu3nIQtn_fRJ-EXbQgFQE2catES09IvnDiWiOiNaHHlzwsFuYJlg77p0PSyqbCBD87XI0fktqsvE236vfbalHAGImY1r0-PJTCn0qsFJ8ariD5Y3RYudEpEs9Ha3qsz3iWCs7SRdk/s1600/4ED58682-265A-433A-AE73-53D7DF1E554A.jpeg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgK45Zu3nIQtn_fRJ-EXbQgFQE2catES09IvnDiWiOiNaHHlzwsFuYJlg77p0PSyqbCBD87XI0fktqsvE236vfbalHAGImY1r0-PJTCn0qsFJ8ariD5Y3RYudEpEs9Ha3qsz3iWCs7SRdk/s640/4ED58682-265A-433A-AE73-53D7DF1E554A.jpeg" width="640" height="621" data-original-width="1600" data-original-height="1552" /></a></div>
It’s certainly miles simpler, not to mention lighter. If I want to easily detach the forestay, I could even use a small gaff saddle shackle.<p>Suzyhttp://www.blogger.com/profile/00333995326888139134noreply@blogger.com0