I recently purchased a Pioneer. The game is in good shape and almost everything appears to be working properly, except...

Like many Gottlieb games of this era, you receive double bonus on the last ball. (I'm currently set for 5-ball play, so that's the fifth ball.) Problem is that when the 4th ball drains and it switches to ball 5, the "Double Bonus" light on the playfield lights very weakly and I can hear a buzzing sound from underneath the playfield. Sounds like a relay is vibrating. Sometimes it will click, the buzzing stops and "Double Bonus" lights up strong and it scores double bonus when the ball drains.

But most of the time, the relay continues buzzing and when the ball drains, it only scores single bonus. I've tried to replicate this with the playfield raised and the buzzing definitely seems to be coming from the bank of relays underneath the playfield which includes the "Double Bonus" relay as well as the five star rollover relays. I assume the buzzing is coming from the "Double Bonus" relay but can't say for certain.

Any guess on what's happening here? According to my reading of the schematic, the "Double Bonus" relay is NC, but the way the relay is positioned it's difficult to tell if the switches are all closed. What's the best way of working on those relays?

FYI - I've had a similar issue with my Surf Champ, where, on the last ball, I will hear a relay buzzing underneath the playfield and the "Double Bonus" light will flicker. Usually if I hit the flipper button a couple of times, it will jar the relay, I'll hear a click, the buzzing will stop and "Double Bonus" lights up fully. I'm guessing it's the same issue.

Thanks for any suggestions!

Pioneer Double Bonus Relay (resized).jpg

The "5" lights up, but it is also weak, just like the "Double Bonus" light. Almost like it's not getting enough juice, if that makes sense.

I did what I could to try to file the contacts on the switches on the Double Bonus relay. But it's really tough to get at.

Played a couple more time since then. When it goes to ball 5, there's still a buzzing relay for a couple seconds, then a "CLICK" sound and the buzzing stops, and both lights turn to being solidly lit. As mentioned, I have the same sort of intermittent problem with my Surf Champ when it gets to ball 5.

HowardR - Unfortunately, I'm still not fluent in schematics. Am I correct that I should start with the BL-RED wire on the AX relay to the GR-WH wire on that relay to make sure that switch is closed? Then, if it is, go from the BL-RED wire on AX relay to the YELLOW wire on the Q relay to make sure that switch is closed? And then where? (Not sure if I'm reading that correctly.)

Thanks for your help and patience...