Covers: North Dakota, South Dakota, Nebraska, Kansas, Minesota, Iowa, Missouri, Wisconsin, Illinois, Michigan, Indiana and Ohio
I have a machine with the SASI host adapter but no hard drive unit and would like to replace it with an FDC so I can use it as a floppy based system. Thanks!
Would be interested in other parts for it as well (keyboard, drives, etc.)
Please contact me at: a s c 1 3 5 (at) yahoo (dot) com or Discord @amardeep_ac9mf
I wait your answer after your question in private message
Did some further work on the machine. The power supply had some cracking Rifa line filters so I replaced those. Nice steady output on all the rails. The CRT filament glows but there is no high voltage. The flyback transformer was hanging off the board. It looks like one of the two mounting bolts had sheared. I fixed that and closely examined the transformer leads for breakage. They looked okay but still no high voltage. The service manual doesn't have a schematic for the video driver board. So I guess that's a dead end. I'll try replacing the horizontal output transistor (assuming the one on the heatsink is it) and if that doesn't work I'll put an LCD in it and sell the CRT tube.
Did some further work on the machine. The power supply had some cracking Rifa line filters so I replaced those. Nice steady output on all the rails. The CRT filament glows but there is no high voltage. The flyback transformer was hanging off the board. It looks like one of the two mounting bolts had sheared. I fixed that and closely examined the transformer leads for breakage. They looked okay but still no high voltage. The service manual doesn't have a schematic for the video driver board. So I guess that's a dead end. I'll try replacing the horizontal output transistor (assuming the one on the heatsink is it) and if that doesn't work I'll put an LCD in it and sell the CRT tube.
Is the CPU board putting out reasonable waveforms for horizontal?
Is the CPU board putting out reasonable waveforms for horizontal?
Well, I didn't get that far since the high voltage wasn't working I just put it away until I figure out what to do next. I'll try the HOT as a longshot but if that doesn't work I'll just ditch the CRT. Troubleshooting the mainboard should be okay since it's all discrete logic and I even have full E size schematic prints for it. Sadly that drawing set (an advantage of once living down the street from the Xerox campus) is missing the FDC circuit. The online copy leaves much to be desired.
Maybe I'm misunderstanding your troubleshooting process (or the hardware), but to my understanding there won't be any high voltage without a horizontal drive waveform.
