HAH, what a coincidence. I'm dealing with a short in the same exact GI string. Check the fuse at F-110. Should be a 5 amp slow blow. On mine, I've isolated the short to pin 7 on connector J-121. Just been putting off opening up the playfield and diving in with a multimeter.

If you need a fuse in a pinch, radio shack sells them. As for the fuse list, there should be a slip of paper posted inside your backbox above the driver board.

Was the diode installed with the band the right direction? When you turned the power on and there was something possibly shorted to something while you were moving wires under the playfield? check all the bulbs/targets wires under the playfield just incase something is just barely touching. If it did blow a fuse this is probably the case.

The fuses you can probably get fom the source/Radio shack. Hope thats all it is and you don't have to trace for broken wires.

I don't think the diode is the issue. I'm gonna assume it was for a controlled lamp in the lamp matrix. GI doesn't have a need for diodes, a string is a simple circuit wired in parallel.

Did you play around underneath with the power on? Something probably broke loose and shorted out your fuse. You may be lucky and the issue resolved with the playfield moved back. Try popping in a new fuse first.

To check a fuse, sometimes you can tell if the filament is toast visually. But sometimes that is hard on the slow blow fuses. You need a multimeter and run a continuity check accross the fuse.

I check for GI shorts by first finding the connectors associated with the blown fuse. I then pull the connectors and check ohms to ground by leaving one lead on a good ground point in the cab, and touching the pins on the connectors with the other lead. Meter should stay infinite ohms or OL, if you get a reading, there's a short on that string.

If that doesn't fix your issue, go ahead and read this section on GI troubleshooting for williams WPC games.

http://www.pinrepair.com/wpc/index3.htm#gi

Looks great, glad you found it.