Konami GT arcade pcb repair

Game would boot to a corrupt screen then reset.  Comparison to MAME suggested it was trying to draw the ROM check screen, so it was possible the RAM used for the screen itself was bad and the reason for the corruption.

The game has 3 TC5535P-A RAM chips on the video board – I held the 68000 CPU in reset so I could use a logic probe on the RAM without worrying about writes getting in the way.  It was obvious one of the chips had a very weak data output so it was replaced and everything worked.  The TC5535 actually seems to be quite a rare chip now – luckily I had a spare from a Nintendo VS board.