here are the pictures
the story step by step again:
1. A "checksum M01" problem appeared.
- I changed the accumulator.
- I loaded in the machine parameters.
2. The machine worked for 2 weeks, suddenly
duirng the work procedure it became "frozen".
- I had to switch the machine off.
3. After switching on the display looked like the chess table (pictures attached).
- Power supply (+5V,+12 V, +-15 V) were OK
- BUT: Accu backup was broken. I corrected it.
4. After switching on it said: RAM-Failure.
- I changed the RAM. (16 pieces - HM62256)
5. Switching on: chess table on the display again!
6. I tried to switch on with CPU and video card only.
Chess table remained.
7. I changed the EPROMs.
Chess table remained.
Finally, I do not have any more idea. I was thinking about to localize the card, which has the problem.
I am looking for a CPU card (Type: 4022 226 2390).
Can anyone help me?
Best regards,
Kiss