I went to a friend's place and did a few repairs. I am posting so others might benefit.
Centipede-
Track ball doesn't track to the left. Switch X and Y connector to verify that it's the tack ball not the pcb board that is the issue. It was determined that the track ball was the issue. Connector were loose. Replace connectors.
Fire button spotty. Found out the leaf spring switch button was sanded. Replacement was the fix. Use a sheet of paper and with contact cleaner on it and press the switch lightly close. Pull the paper until no more black gunk is smeared on the paper.
Star Wars-
DOA.
Found old foam on the back side of the connector. Washed off with a brush and water. Rinse with alcohol. Let dry. The old foam was use to prevent the back plane of the board from shorting out on the card cage. Old foam was wash off with water first because you don't want melted foam all over your board. Connectors clean with pink eraser. Works now.
Assault -
Diagnostic switch works but the game throw up a square graphic on screen.
2 issues
Switcher 12 volt side was at 13.8 volts- Replace power supply
Replaced the 68000 -12 CPU
Works now
Centipede-
Track ball doesn't track to the left. Switch X and Y connector to verify that it's the tack ball not the pcb board that is the issue. It was determined that the track ball was the issue. Connector were loose. Replace connectors.
Fire button spotty. Found out the leaf spring switch button was sanded. Replacement was the fix. Use a sheet of paper and with contact cleaner on it and press the switch lightly close. Pull the paper until no more black gunk is smeared on the paper.
Star Wars-
DOA.
Found old foam on the back side of the connector. Washed off with a brush and water. Rinse with alcohol. Let dry. The old foam was use to prevent the back plane of the board from shorting out on the card cage. Old foam was wash off with water first because you don't want melted foam all over your board. Connectors clean with pink eraser. Works now.
Assault -
Diagnostic switch works but the game throw up a square graphic on screen.
2 issues
Switcher 12 volt side was at 13.8 volts- Replace power supply
Replaced the 68000 -12 CPU
Works now

