One switch does not show in the switch test.
A single switch does not register
Cause: Bashed-together or misadjusted contacts, a broken microswitch, a wire off the lug, a bad diode, or a broken chain wire.
Checks
- From above, check whether an airborne ball has bent the contacts.
- On a microswitch, check the actuator arm and listen for a click; no click means it is broken or misadjusted.
- Check the wires are soldered, and check continuity to the next switch on the same column (green) or row (white) wire.
- Meter the switch: from the common lug (the one the diode band goes to) to the normally open lug should beep only when pressed; to the normally closed lug only when released.
- Diode-test the switch diode.
- Check other switches in the same row and column.
Fix
- Clean leaf contacts by pulling a business card between them; never file them, they are gold plated.
- Replace the switch if it is faulty. If a whole row or column is dead, the fault is likely on the CPU board.
Systems
Related tips
- Most switch matrix faults show up as row faults
- One switch shows closed though it is open
- A string of switches all stopped working
- What a bad switch diode does
- Switch only works now and then in switch test: reflow and clean it
- An entire switch row shows closed all the time
- Which switches are outside the switch matrix
- 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)