Hi Dave,
The optos on WPC games can go intermittent. Another way to test the optos is to run the 1st switch test in diags. Leave it on this screen for 1/2 hour or so and see if any optos/switches trigger by themselves. You can also block each opto with a piece of paper and see if it responds correctly.
The GI connectors do burn on these games after a lot of use but this will normally cause GI lighting problems and shouldn't cause a problem with optos.
regards Derek
