After shopping out my TZ (specifically after changing the rubber rings on the mini pf), my machine started to flake out. At first, it was resetting after a few seconds of play or when both flipper buttons were pressed at the same time. After a few power cycles, I got the "Check Fuses F115 and F116, J112 and Opto 12v Supply" error. Fuses looked good. A switch test revealed that none of the opto switches were working. Next I started checking the voltages on the power driver board. the 12v and 5v test points were registering double what they should have. When I touched my multimeter to the 20v test point at TP7, the machine went nearly dead; all insert, GI, backbox lights went out and no DMD. Only a couple of my mods stayed lit (Robby and the mind orbits shooter rod). I cycled the power and still everything out. Then the speakers started to emit high pitched static. The volume starts off low and gets louder and louder very quickly. I thought maybe just my opto board was fried but now I fear the whole machine is toast.... any help would be greatly appreciated.

No...definitely not. Machine was off and unplugged during the entire shop out.

Update... Looks like my multimeter was on the fritz and that is why I was having issues with the strange TP readings. I must have blown F115 when testing TP7. After replacing the fuse, all of my lights are back on but I still have the "Check Fuses" error and none of the optos are workning. I have verified that I have power at the MPU board and under the playfield at one of the Opto power connectors. A couple of new things: when I power on the machine, the gumball motor kicks on and does not stop; the outhole solenoid powers on and stays on (and quickly overheats) and the clock is not working. When I perform a switch test, switches in the same row and column as the failed optos are all testing fine, which would seem to rule out the MPU board. Could all of this be related to a bad opto board?

Thank You! Okay...so I had a faulty mod piggy backing on the driver board connector that drives the optos. Removed it and all optos are back in working order including the clock. The gumball motor and outhole solenoid are still continuously running/locking on. Any thoughts?

So I have checked the wiring and everything seems to be in order there. I can trace both of the issues back to J107 on the power driver board. It provides power to the gumball motor and the outhole solenoid. It also provides power to 13 other solenoids. 7 on the same pin as the outhole. None of the others are locking. I have metered the power output on J107 and it seems to be extremely high at 80v. It should be +50 on two pins and +20 on the other. Is there any way to test the transistor?

Yes. Both of these issues started only after I shorted my 20v test point. I believe the initial "Check fuses" issue was caused by a switch that was stuck closed on the mini PF after I replaced one of the rubber rings. At that time, I did not have any blown fuses. When I shorted the 20v TP, F115 blew and I lost power to all of the playfield components. After replacing the fuse, power came back and the gumball and outhole issues started. I am guessing that I have fried whatever is regulating the power to J107. The gumball motor is driven directly from the 20v pin on J107 and the outhole solenoid is the first in the chain on one of the 50v pins. Strange thing is the other 50v pin does not seem to be locking any of the solenoids that it drives.