Received a call from Dave Kerr regarding the Mod 80. He says he has a few 1702 EPROMS and maybe a few odds and ends left, but not much else. Plan to meet him at HAMEX in Brampton on the 18th.
I finally figured out how to drive this teletype using an Arduino. Here is a short video showing it working.
Wrote letter to Dave Kerr (VE3FJK), the original owner of the Mod 80. Hopefully, he can answer a few questions I have.
Worked on Mod 8-9 board. Did some reading of the material that I got from Zbigniew. Turns out that it’s a ROM EPROM and RAM boards all in one. It has a mystery chip (all markings rubbed out). According to the info from MMM, it’s likely an 8316 ROM. Will have to try and read it and see what’s on it. There is also a single 1702A EPROM chip on it as well.
De-soldered the ROM chip and fitted a socket. I also added remaining 1702A chip sockets and replaced a broken 0.33 uF cap.
Wired up a power connector and lines from TTY in+, TTY in-, TTY out+, TTY out- lines and powered up the UGC-129 teletype machine. Machine appears to power up well. Ran some tests but ink wad too dry to really tell much. Resurrected ink with WD 40. Sometimes the beast prints well, and other times it prints garage characters. Turns out that the stepper motor used to rotate the print octagonal die behind the paper over or undershoots and is not perfectly aligned. I hope it’s a stepper motor issue and not a control circuit one. Troubleshooting that will be difficult without schematics.
The stepper in question is a 5 wire motor with an encoder. Hopefully, to troubleshoot, I can swap it for the page advance stepper which appears to be the same type.
She's alive! Powered up the teletype and ran it through a few tests.
Visited Professor Zbigniew Stachniak at York University to gather more info on the Mod 80. He has a tremendous amount of documentation and an example of almost every different board made for the Mod 8/80 including the Mod 8-1, 8-2, 8-3, 8-5, 8-6 & 8-7. He offered to foot the bill if I designed up board layouts in a format that could be sent to a board manufacturer to make reproduction boards.
Found out a bit more about the mysterious Mod 8-9 board. It was an incredibly productive visit. Expecting to receive some scans of the material that he has shortly.
Started some restoration work on this early microcomputer (circa 1974). Soldered in a proper teletype connector (the big shiny bit), a replacement Darlington transistor, and repaired some damaged traces. Just waiting for the proper Molex socket and that should be it for this board. Then it’s on to the different daughter cards.
I think I’ve found geek heaven! The Toronto Electronics Surplus store near Keele and Lawrence. I love exploring places like this. You never know what interesting things you might find! Managed to find an old teletype machine. An AN/UGC-129.
Charles Baetsen holds a Bachelor and a Master's degree in Engineering Physics from McMaster University in Hamilton, Canada.