[Discussion about Jonathan's S-100 workshop in the CDL facility.] I spent time in Jon's workshop, mostly observing. I also enjoyed seeing the IMSAIs in repair. And it's good to see people learning to build kits from components. Jon and I tag-teamed on one IMSAI fix. He was looking up details on a front-panel signal that wasn't pulsing; but could not find an early IMSAI schematic. While he was looking, I reverse-engineered the circuit to trace it backwards. He found the problem from the schematic, just as I traced it back, to the same one-shot 74121. Replacing it solved the problem; apparently 40-year-old monostables tend to fail, Jon said at the time. There were a number of people in the workshop, exercising their collective knowledge of these early vintage computers. It was good to see them all, not just the S-100 machines. And it should be noted: there was a nice exhibit of early S-100 computers, thanks to Mike Loewen. I'm certainly in favor of another workshop devoted to more 1970's computers, if not only S-100 computers. If it's done during a swapmeet, I suggest not much work will get done in the morning, people will be swapping. So that eats into a day of repair. Regards, Herb Johnson sometimes called "Dr. S-100" -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT comcast DOT net