Alpharetta, GA
Actually, what this is telling you is the game THINKS all the optos are not working ...
How does it know that? It's looking for the switch input signals. You have +12 on your optos, so your issue isn't there.
+12 for the optos comes from the +12 unregulated supply.
However, in your case, your issue is in the switch matrix itself, which is a different power supply circuit.
On WPC games (both classic and 95), the lamp matrix +18 provides the feed to a 7812 voltage regulator, which provides +12 digital to the CPU for use on the switches. All switches. Direct, coin, flipper, and matrix.
+12 digital has its own fuse ... try replacing it. If it immediately blows again, chances are the ULN2803 on the cpu is fried ...
