Test a lamp socket diode in place
Steps
- Turn the game off; the bulb can stay in and the diode stays soldered.
- Set the meter to diode test and place the black probe on the banded end.
- Put the red probe on the other end: expect roughly 0.4 to 0.6 V.
- Swap the probes: the meter should read open (no value).
- Any other result means the 1N4004 should be replaced. Diodes on 555 lamp boards test the same way.
Systems
Related tips
- Test each lamp column driver with a test lamp
- Lamp diodes sit on small boards at each socket
- Diode orientation on #44/47 lamp sockets, and 555 sockets
- Testing a lamp diode
- Test a 1N400x diode on a coil, lamp socket or switch
- Two lamps flash together in the single lamp test
- Lamps in a row or column light twice per sweep
- Why diodes on 555 lamp boards crack
Source: Repairing DataEast 1987 (Laser War) to Sega 1995 (Batman Forever), Part Three, Clay Harrell (pinrepair.com)