This is probably simple, but better to ask vs replacing a lot of TIP102's, pre-drivers, and logic over and over again.
Special solenoids aren't locking on at pwr on here, but Q75 blows up when triggered.
I initially replaced q75 as it was blown previously. Replaced the 4401 pre-driver and 7402 @ u45 as well, as the high signals on IJ18 were not present. Everything else tested fine in the area. Tested out U50 and U49 as well. Pop coil to Q75 was melted previously, replaced coil. Coils have proper voltages, aux pwr board coil diodes are good, TIP36Cs for slings are good. Switches tested ok. Fuse values are correct everywhere. I figured all was well.
But when in test mode, activating Q75 via pop switch causes it to violently fail, take out pre-driver + U45 7402. It seemed almost delayed, whereas I didn't see it coming to shut the game off immediately. All other special solenoids did not activate either, minus the right sling. Q75 was the last switch tested and it blew up and I had to replace the driver, pre-driver and U45 again.
With IJ18 & 19 disconnected, everything else is fine. I have barakandI's solenoid saver on the way before I test again.
Any ideas where to inspect next? PIAs? I've usually seen this the other way around where coils just lock at pwr on, and replacing upstream logic + drivers takes care of it.