My newly acquired Who Dunnit pinball machine has a strange problem. It plays fine for game after game, but after any extended period of inactivity, the machine will begin to behave strangely. "Autofire" (ball save) will fire over and over, but flippers won't work at all. When you finally switch off the game to reset, the machine always powers up with the following error message:

Check Fuses F115, F116, and Opto 12V Supply.

Fuse F116, a slow-blow 3 amp fuse is always blown. Replace it and the game functions normally again for awhile---then several games later, same problem again.

I've tried burn-in to induce the failure, but nothing happens.

Any clue where to begin troubleshooting this one?

Thanks in advance.

Abby & Les Rayburn
Maylene, AL