I've got a restored, clean, Surf Champ that does not countdown the double bonus correctly. Single and triple bonus are fine. However, 90+% of the time, the double bonus short-changes me. What should be a 20k bonus might give 14-18k. I've cleaned the motor switches, bonus unit, and 1000-pt relay. It does this for all players.

On the working single and triple bonus step-down, the bonus subtract coil pulses once per bonus number, however it tries to pulse twice per number on the double bonus which in turn makes the bonus unit seem to skip some numbers. Not sure what actually pulses the 1000 pts during the bonus countdown. I have the schematics, but not an expert. Thanks for any help.

Thank you, but it is set on 5-ball.

The first part is verified. Yes-5k per 120 degrees on single bonus, 4K on double and 3k on triple. Sometimes I’m getting all 4K per cycle on the double.

9b alone is engaged when I’ve got double qualified

10b and 11b activate at start of ball 5 which gives you double bonus off the bat

If you earn the triple bonus on ball 5, 9b and 8b also activate.

Not sure if this is what’s supposed to happen.
For some reason, just not getting the 4 pulses per cycle every time on the double.

So 8b is not engaging on the double. Only on triple. 8b does not have its own coil as it piggybacks off of 10b when it’s activated.
I’ve searched high and low and cannot find anyone else who had this issue. I’ve had a few Surfers and Surf Champs over the years and this is a first!

During double bonus, it's off by even and odd amounts, because maybe 1 out of 4 times if I have just 1 bonus light lit, instead of 2k, I get only 1k. Thank you very much for spending the time to try and figure this out. Much appreciated!

Finally solved!!! I actually had a secondary problem of the ball count not advancing about once a game. Both issues ended up being related. The problem causing both was with the score motor 2C switch stack actuator. It was in the ‘S’ position like all of the other 4 or 5 actuators on the score motor stacks, but it turns out that 2C is the only one that’s supposed to be in the ‘L’ position. Saw it on a Pinside thread elsewhere today where someone had that issue on another Gottlieb pin of same era. I think it was 'DaMoib' who gave that correct fix too so thank you! The detailed score motor card in the Surf Champ manual specifically calls out for all the other actuator positions to be in the ‘S’ spot, yet says nothing about the 2C stack-almost assuming the ‘L’ to be the default. Very tricky one to figure out.