It's alive!
All solenoids, lamps and switches working. Was quite the day of troubleshooting. I lucked out and found someone on IRC who was VERY knowledgable with the heart of a teacher and got walked through troubleshooting the WPC driver board. Learned bunches.
Upon further diagnosis, I found out the entire Row 1 of the lamp matrix was stuck on - but the transistor was fine! The lamp matrix is 12 volts, but it 'strobes' 18 volts to produce 12. When the column or row locks on, it eventually draws enough to blow the fuse. So, the stuck row caused the fuse to blow. Pulled the lamps in that column, replaced the fuse, and the game was fine again.
Apparently, this board got nailed REALLY hard by something before it came to me. I had a problem with 3 flashers and 1 coil locking on as well, and after looking at the schematic, I found that the lamp row, 3 flashers and coil all connected to D0 on the driver board. After hooking up the logic probe, it was obvious that something was pulling D0 low when it should be pulsing.
I ended up replacing U1, U2, U3, U4 and U5 because pin 2 on all these chips was shorted. Logic probe kept finding a bad chip and D0 was pulled low instead of pulsing, I'd remove the chip and retest, and it'd still be pulled low! Long story and I'm not gonna go into it, but the driver board took 3-4 hours to straighten out.
Adjusted 3 switches, replaced a bulb that was burnt out, reflowed the solder on the DMD driver board (had an intermittent problem with the DMD driver garbling images/text and failing the RAM test until it'd been on for 10-15 minutes, as expected, there was a cold solder joint) and now, it is 100%.
Time to return to assembly :)
