I've been working on a Time Machine that has had an issue with Flashers 7,8, and 9 locking on upon boot and the laser kick not working (laser kick would lock on upon boot, but then would disengage when the blanking turned on and never engage thereafter in game or coil test).

Anyways, the diode on this looked to have been replaced at one time and I thought that it may have been installed backwards and causing my issue so, like an idiot, I flipped the diode and re-booted the pin. The coil locked on as usual, but after the machine booted to blanking, the coil remained engaged and I started to smell smoke so I quickly turned off the machine and reversed the diode back to its original position. Re-booting, F5 on the PPB immediately blew, where I believe this is due to the laser kick coil now being shorted. So now I've cut out the laser kick coil and capped both lines to it and F5 no longer blows, however, the knocker coil engages upon boot and shuts off during blanking (this may have been occurring before without me noticing due to my focus on the laser kick, so not quite sure on this one).

So here's the new issue that's occurred after all of this. When I go to test each coil individual, the knocker and the ball eject (and possible others) engage on every other coil fire in the test. What's more, when I touch the coils to the ball eject and knocker, even when just leaving the game in attract mode, they are getting hot ridiculously fast. With all this being said, what all could I have damaged by reversing that one diode and any ideas on what I should start checking first? It's hard to test with power on, as I don't want to leave it on too long with it overheating and start shorting various coils. I have spares of each board and have already tried swapping the PPB, but no change. I'm also a bit nervous of doing these boards swaps in case the issue is with a coil back-feeding and possibly damaging components on the boards.

bump for any feedback or guidance on this

I wish I had seen your post earlier, as you were definitely correct about the IC, and that would have saved me some time tracing everything back. Also found a few other problems when I had the MPU board out. Hopefully this will help anyone who may encounter something like this in the future:

The flasher issues were being caused by a bad TTL7408 that controlled them, so I replaced this with a 14pin socket and a new chip. When I had the board out, Q46 also read bad, so replaced that, which fixed the solenoids firing on side L (I think it's that side), except the kickback and VUK were still firing on that side. I then found that Q5 was bad on the PPB, where after replacing this, all SEEMS to work now. I'll post more if any other issues come up, but am pretty happy with the outcome thus far.