OK... Got a good one here..
Board worked perfectly fine, and then decided to show customer, and well, all the sudden it got random sprites.. BG images are fine.
Swapped the 6016? on the Video Board, and the CPU Board, and even swapped the NVRAM.
it will play fine, then random sprites then fine, then random sprites.. almost like a flapping data latch in the object ram load section? any ideas where to look , getting schematics from customer tommorrow, so should be easier to source.
does not appear to be the 4 93422 or 23??? ram chips on video board.
will post video later tonight.
Service History: Got board 100% non-working, had two bad z80's, wrong ram on io/ and two dead roms.
sprite ram does test 100% good in fluke 9010 long ram test.
Board worked perfectly fine, and then decided to show customer, and well, all the sudden it got random sprites.. BG images are fine.
Swapped the 6016? on the Video Board, and the CPU Board, and even swapped the NVRAM.
it will play fine, then random sprites then fine, then random sprites.. almost like a flapping data latch in the object ram load section? any ideas where to look , getting schematics from customer tommorrow, so should be easier to source.
does not appear to be the 4 93422 or 23??? ram chips on video board.
will post video later tonight.
Service History: Got board 100% non-working, had two bad z80's, wrong ram on io/ and two dead roms.
sprite ram does test 100% good in fluke 9010 long ram test.


