Quoted from PinballManiac40:Just trying to help identify which coils/flashers use power from the F104. Although, the diagrams from Tlamb should show the same results.
If you have no coils/flashers firing during the tests, make sure you close the coin door for these tests.
The blanking circuit on power up will not keep a locked on transistor from frying a coil.
Ah, gotcha on the fuse. I thought we'd established what F104 fed, but maybe not.
True on the blanking, but if it were a locked on transistor, he would hear the coil turn on during power up. He hasn't mentioned this. He said he checked the coils for shorts and there were none, so it doesn't sound like it's a combination of locked up transistor AND shorted coil that wouldn't turn on.
A good test, might be to watch F104 and see if it blows before or after the blanking completes. Because if it immediately blows on power up before the MPU boots, then it's a good bet that it's a shorted transistor. If it blows after the MPU has booted, then it's likely a shorted flasher in attract mode.
I still vote for removing J122, and possibly the other connectors as the previous poster suggested, and then reinstalling one at a time. Would narrow the scope.