Wolfman9291
Member
- Joined
- Sep 13, 2022
- Messages
- 22
Hello all I picked up some Kaypro equipment recently and I’m currently working on a 2x. The issue I’m having is no display. I started looking at the crt board and found no high voltage checked all the transistors and caps on the board along with the traces and everything looked good I replaced several electrolytic just to be safe, I was told that the high voltage is controlled by the horizontal portion of the board. I then pulled the o scope and fluke meter out. Theres 5 volts dc on the vertical but no signal. The video and horizontal are at zero volts and no signal. I then changed out the video ram and installed a blank character prom to do the 9, screen fill. Still nothing. Could a bad 6545 video controller stop this? Now I don’t think the computer is running. The voltages are good but the drives don’t seek. Would a bad z80 processor or bad boot prom stop the whole machine? This is my first cpm machine and I got a whole bunch of disks with it. I have the technical manual downloaded all ic’s were pulled and reseated one at a time and the board traces and solder joints were checked. Thanks all!