Taito Elevator Action arcade pcb repair

Game ran and played but with corrupt graphics. I was able to swap the top ROM board with a known working one which made no difference which meant the fault was either on the CPU board (which puts the data into VRAM as well as the addressing of the tilemaps), or on the video board (which uses the VRAM output as well as holding the 6 VRAM chips themselves).

In fact this turned out to be a simple repair – one of the VRAM chips was bad with an address bus fault – so it was just putting out data for the wrong address over the top of everything. With new VRAM installed everything was fine.