27891Re: Bill's workshop
- Oct 29, 2012--- In email@example.com, "Jeffrey Brace" <ark72axow@...> wrote:
>Nice write-up Jeff! I really wanted to be there for the PET
> From: Evan Koblentz
> Sent: Sunday, October 28, 2012 4:04 PM
> > What I really want to know is who won the first-to-smoke award. Otherwise,
> > my title from last time carries over. :)
> I got there 11pm on Saturday, so unless something happened before I got
> there, then the honor goes to Bill Degnan. He smoked his arm. Actually he
> burned his arm on a soldering iron, so I don't know if that counts ;) Ian
> and I joked that we should burn the Commodore logo into his arm as a badge
> of honor ;)
> Bill can fill you in on what went on before I got there. But...
> Ian Primus fixed and cleaned his Zenith Terminal.
> Bill and John worked on getting the teletype working with the Altair 8800.
> It printed a "D" ! Everyone was in great anticipation of the "D" coming out
> and there were great cheers. We are such geeks. :) They can give you more
> Doug worked on his TRS-80. I'm not sure if he got it completely working.
> I'm not sure what others were working on, but we stayed up until 2am and
> then Doug left. The rest of us went to sleep and woke up at 9am. I woke up a
> bit later.
> So I got out the MARCH PET. And Ian Primus got to work on it. I greatly
> assisted him and learned from him. Bill provided documentation and two
> parts. Ian got it to work ! The problem was with the monitor. Ian replaced
> a 10k ohm resister that had burned out (that was the smell that Jeff Frady
> smelled many moons ago) and the monitor pretty much worked after replacing
> the resistor. But the video was still jumpy, so he replaced a 1 micro Farad
> capacitor that looked a little worn. But the monitor was still jumpy. After
> some switching around a know good monitor and board (provided by me), we
> realized that the monitor or its board inside the monitor was not the
> problem. One minute the video was stable and the next (after checking to
> make sure there was a secure connection) the video was jump again. I noticed
> after this happened three or four times and pointed it out to Ian. So he
> realized what was wrong. It was the soldering of the video connector on the
> motherboard. Specifically the video monitor's connection to motherboard. It
> needed some extra solder to make a good connection. Ian also soldered up
> some other places that looked like it needed it. So it's pretty much working
> and we had time to test the cassette drive. But were not able to fix in
> time. We also noticed that some keys on the keyboard didn't quite work. So I
> will look into cleaning it, would should be doable for me with some time.
> Another thing was Bill Degnan was going to try to use his PETvet to diagnose
> what was wrong with my PET. He was hesitant because, after using in *his*
> PET, it stopped working. Ian noticed how the 6502 easily came out of it. Ian
> noticed that the pins on the PET VET were too big and stretched out the
> socket on the mother board. So the original 6502 didn't have a good
> connection in the socket. So Ian was able to replace the socket and thereby
> fix Bills PET. Ian can explain the exact technical terms. So if anyone is
> going to get a PETvet, beware and take precautions. I will have to
> investigate further to see if anyone else has had these problems. I will try
> to contact the guy who did the VCF exhibit with the PET VET. For anyone that
> doesn't know the PETvet is a RAM and ROM replacement board for the Commodore
> PET, and potentially other 6502 based microcomputers. The PETvet connects to
> the 6502 socket in your PET, and allows you to select your boot ROM via
> jumper settings. It also allows you to view the memory of a running PET
> using the replacement RAM by halting the CPU and sending the memory contents
> over a serial port. This web site has more info:
> We wrapped it up and left around 5pm.
> Thanks to Bill Degnan for hosting ! It is very generous and hospitable. I
> think that everyone sometimes just needs the right environment to be
> productive in fixing computers (free from other distractions). When we are
> at our own home, then we get distracted by day to day things. An environment
> like this allows everyone to focus on one thing.
> I look forward to researching more about the PET and going to the next
> workshop. It gave me an understanding and a basis to start with my research
> about PETs and other aspects.
> Jeff Brace
work, thanks for detailing it here.
I had my TRS-80 Model I keyboard about 1/3 off the circuit board
while there before we bailed Sat night/Sun morning.
(But not before busting Bills "wedding china" coffee mug ARGH)
Got it all removed last night! 18 inches of solder wick later
and painstakingly careful prying.
Now I can get at each individual switch. Hard but worth it.
Researching switches now some TRS-80 site folks are helping me
find other keyboards w/ the same switches that might be far less
beat. Or I can refurb these.
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