The only thing I can see is the R Eject Relay. Either sticking or self energizing switch too close. You can put a strip of paper in self energizing switch to see.

I agree that it looks like the Right Eject relay is not releasing. Based on the schematic I think the eject holes are supposed to advance the Bonus by two steps:
Blue Chip Bonus SU (resized).jpg
There are two Score Motor switches wired in parallel that will both fire the Bonus Step Up solenoid when the Center or Right Eject relays fire.

BTW, the schematic on IPDB.com could be better. If you have a good copy consider having it scanned and sending a copy to them.

/Mark

I spent some time this afternoon on it.

Ejects seem to be doing better I think they might have been mechanically hung up at their respective relays and needed some exercise in releasing. Switch stacks on the score motor seem sound but verified too.

We are still working on the 10s and 100s scoring simultaneously.

Did you check the 9th position switch on the 10's reel? If it's always closed it will make the 100's turn also.

Yes it’s working fine. It has to be somewhere on the playfield. We have that tiny Jones plug hooked up wire by wire with alligator clips. If I sever the top right it starts working fine. Alternating relay appears fine and in adjustment too. Nothing obviously crushed

If either the B or C switch on the Change relay is out of adjustment so all 3 terminals are connected together, the 10 and 100 point relays will activate together.

pasted_image (resized).png

I isolated both options with tape still does it. Next time I’m at Dave’s I’m considering cutting the wires from the blades. Not the common though