PCB Repair Logs Lethal Enforcers
As always first thing I look for on any PCB im about to repair is the F branded Fujitsu logic chips. This brand is the devil! 95% of the problems on pcbs I've repaired over the years are due to these. Doesn't even matter what type of Fujitsu logic either, they are all dying.
Problem: Board constantly resetting, won't boot.
Fix: Dead 74ls138 @ J2 (F chip )
Problem: Games running but has graphics corruption and vertical lines through the graphics.
Fix: Very common problem I'm finding on any board with Mask roms. Doing a mask rom test revealed a bad rom @ V8. Put a 42 pin socket in and replaced it with another mask rom I had on a parts LE board. The equivalent EPROM for LE is 27C800 8 meg 16 bit rom.
Problem: Colours messed up.
Fix: Dead outputs on 74ls151's @ J8 and J10. Seen this issue before and the other pcb I looked at was loaded with all F branded 151's . I expect the rest of the 151's will die on this board soon enough.
Problem: Player 1 trigger not working.
Fix: Using the schematics I traced the problem back to a bad 74ls253 @ M3 (F chip)<Bbr>