Pit Fighter Repair Logs
Symptom: Game controls not working
Replaced bad 74LS244 ICs at locations 70B and 75B. Tested board.
Symptom: Garbled graphics
Swapped IC S30 with a parts board to fix. Burned a replacement GAL for the parts board.
Symptom: No video output
Traced the missing video signal back to the output latches. Signal was on the input side but not crossing the IC. The clock signal was missing on the latches. Replaced the GAL at 65D to fix.
Symptom: Loses most sounds after heating up
Most audio signals disappeared after playing the game for about 10 minutes. Cooling spray had no effect. The audio signals would come & go. Sometimes they would work but most of the time they wouldn't. IRQ lines were going dead when the sounds disappeared. Replaced the 6502A CPU on the sound board to fix.