OP

Quoted from xeneize:

Finally figured out the left curtain issue!
After verifying power to the coil, verfiying connectivity to the header pin, checking both the coil and the diode for power and orientation, then swapping them out, and then disassembling the mech and reassembling, I was still stumped. The right hand side had always worked and would pull back "most" of the bead strands on the right, but not all of them. I chalked it up to being a poorly designed gimmick.
After exhausting all other ideas, I just held a magnet up to the beads - and guess what - 7 of the 10 of them didn't budge. For whatever reason, the majority of the beads weren't ferrous. I had a fresh set on hand to install once everything was cleaned up - purely for cosmetic purposes. Set a magnet next to those, and they all respond. So, there you have it - sometimes the answer is a simple one and the least likely to be suspected.
Now, if I can manage to conquer the reset issue - once and for all - this game will actually be 100% again.

OP

Quoted from xeneize:

cadillacmusic

I concur. Last night I did more testing and it definitely only happens when more than one coil is activated. The factory spec autolaunch coil was most likely triggering it by itself as it is the most powerful coil in the machine.

Game had been in a fire, but the boards were replaced with new, factory boards by the previous owner. All of the female connector pins have been replaced. I can measure the voltage at the chip in question - are you referring to U-218? Is there a leg in particular where I should measure, or just put one lead to ground and use the other to probe all legs.
terryb

I do have a Fluke DMM so I should have an adequate tool. Where do you recommend I clip my leads to get the most accurate reading during gameplay?
Thanks, guys!