Burnin' Rubber (Bump 'N Jump) repair

This was bought in a job lot and listed as untested, I thought there was a good chance it would work after making a jamma adapter for it but no such luck.

Powered it on and got nothing but a black screen, I could coin up and there was music so it was mostly working. Checking with a logic probe I had sync but no red, green or blue, all three pins were floating.

I decided to check the bottom pcb with the trusty hp logic comparator, this was a little tricky as the top board covers most of the bottom one. I was able to flip the top pcb to the right being careful not to short anything to the jamma adapter. I eventually found a bad 74LS74 at B11.

Bad 74LS74 removed.

New one fitted.

 Repair complete.