Tell whether a phantom closure is on the CPU board or the playfield
Steps
- Unplug CN8 and CN10 from the CPU board and enter switch edge test.
- From the manual, find the row and column of the switch that sets off the phantom event.
- Join that row and column pin on the CPU board connectors with a jumper and a diode, as in the column and row tests.
- If the phantom switch does not appear, look for the fault under the playfield; if it does, the CPU board is at fault.
- On the CPU board, test the 1k x 8 network RA6, which can cause intermittent phantom closures; replace it if in doubt.
Systems
Related tips
- Switch row or column error: CPU board or playfield?
- Switch column (drive) circuit on the CPU board
- Switch row (return) circuit on the CPU board
- CPU connector CN8: switch column pins and wire colours
- CPU connector CN10: switch row pins and wire colours
- One switch column dead: parts to check in order
- One switch row dead: parts to check in order
- Whole switch column dead after working under the playfield
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)