King_Corduroy wrote:Hello guys today I went around to the local recycling centre and spotted this laying in the pile of junk! I couldn't believe it! […]
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Hello guys today I went around to the local recycling centre and spotted this laying in the pile of junk! I couldn't believe it!
Unfortunately there was no keyboard with it and I cannot get it to do anything for the life of me, I looked at the manual online but it's pretty darn vague as to what could possibly be the issue. So basically since this is my first time ever using or owning a serial terminal I kind of want to know what I'm looking for here to know if it is indeed alive. I'm probably going to hold onto it either way (especially if I can get a hold of the matching keyboard somehow.
Also how can it be used today if indeed it does end up working?
Here are some pictures I took of it after (and during) I cleaned it up:
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I was one of the designers of this terminal. I designed the keyboard and wrote some of the code. My ASCII initials are in the character generator at character location $FF. The overriding design goal on this project (code name "Pegasus") was to produce a terminal cheaper than the LSI ADM-3 and its ilk. So, single main PCB with all the circuitry on it (HV CRT, AC line voltage and microprocessor), no video subchassis, we rolled our own keyboard.
The keyboard is custom, so your best bet is to try to find another terminal and keyboard. It's a very inexpensive design, just a shift register and some analog muxes across a capacitive key array. The processor shifts a one through the shift register, and the analog muxes will see a pulse if there's a key pressed. Being a capacitive keyboard, the analog muxes that detect the pulse are high impedance and they will eaily pick up the flyback pulse if the keyboard is placed on top of the terminal...except that I carefully wrote the code not to scan the keyboard during the time the flyback pulse is generated.
I uploaded the manual and main board schematic here:
https://www.scribd.com/doc/146282825/Data-Gen … eference-Series
The power supply is a custom off-line switcher, designed by a guy named Mike Ingemi. This was before switching power supplies came in nice IC packages, and it's a work of art. However, it can fail. Another failure mode is related to the fact that the HV anode connector for the CRT is located right on top of the microprocessor when the lid is closed! In retrospect, not a great idea. That's what the little metal shield is about.