This one has me a little stumped. The Torpedo upkickers (Honda and Bison) on the lower half of the playfield are randomly weak and seem to be getting weaker as time goes on. They always work, but the ball often kicks to the drain or the close flipper. There are still times when the ball flies out properly just make the problem harder to solve.
When they first started dropping the ball occasionally, I replaced the sleeves and inspected everything. That didn't help. So then I replaced the coils, the sleeves and the upkicker rods and springs... no difference.
The problem doesn't seem mechanical at all. To me it seems like there isn't enough of a boost of electrical power when it's needed. Even the sound is pathetic when this happens. My best guess is a dying capacitor, but I'm not sure which one to go after. The big black one on the driver board seems like a place to start, but randomly replacing things has produced 0 results so far.
I'm putting this out there to see what you all think. Unfortunately, I only have one system3 and can't just do some board swapping to see what works. If there are any Richmond VA based System3 folks that want to play board swap at my house, I can pay them in beer.