The graphic issue with vertical stripes could be the video ram buffer chips which are the rows of TC51832AFL in locations 9M-9X and 12M-12X, or the nearby LS374 chips, that's if the corrupt lines are shimmering as the video ram is double buffered. Another possibly more likely candidate are the mask roms on the OBJ memory expansion daughter board. Could need the surface mount chips resoldering, or in my case I've had a few of those mask rom chips just die as I believe they're made by Fujitsu. Also check for dry solder joints on the connector for that daughter board. Try swapping the rom expansion from the board with the blue issue.
Missing blue colour could be the surface mount filter array FL15 near the JAMMA edge connector has cracked or has a dry joint. These just seem to randomly break. Also check the video DAC resistor SIL arrays, there's three of them near the SHAPE mask rom at 5M.
lix2022-05-30 13:34:09
