Got for repair this original Robocop 2 PCB by Data East :
Board booted up and plays but sprites were completely absent :
Sprites are generated by the surface mounted custom ASIC marked '52' :
Schematics for this board are not available but I was able to find the pinout of this custom IC on the ones of Desert Assault.There are some input timing signals to the '52' custom IC, when I went to probe them I found pin 98 (labeled 'VCNT' on schematics) stuck high :
I traced the pin back and found on the path a gouged trace on solder side :
I patched the trace with some wire wrapping wire and sprites came back :
Job done, anpther repair successful accomplished.
