I finally summoned the courage to disassemble and de-gum the bonus unit (had cleaned as best as I could without fully removing the shaft but was still hanging up occasionally). I'm confident I got everything back together and properly aligned, and that thing snaps back with authority now!

However, now when I fire the machine up it runs through the reset cycle and then immediately starts firing off 100 points over and over while the score motor runs.

I don't think anything I touched would cause this so I'm confused and not sure if it's just a coincidence brought on by tipping the playfield all the way up against the back box and down?

The only 100 point items are the 2 standup targets as far as I know. The drops score 300, which, actually I don't know how that works to repeat the 100 3x for each of those. The loop I'm stuck in now is a slower repeat than the quick 3x staccato of scoring 300 though.

Any advice?

Also I know it's something on the playfield, if I unplug the Jones connectors to the field it doesn't get stuck in the loop.

Solar City

No pauses, just the same repeating ding ding ding ding over and over at the same pace as the score motor. C appears to be firing at the same pace, D looks like it's not doing anything.

To be clear there is a pause, but it's the same consistent pause between every ding. No groups of three or five, just the same consistent rhythm.

Finally had a chance to spend some time on this again. There was a wire near one of the upper drop targets that had moved and was pressing on a switch causing the issue. Thanks for the ideas!