Grand Prix
Williams, 1976The problem I am having is with the right bonus unit. If i turn the game on and hit the start button everything resets as it should except the right Bonus unit will drop back to 0 then it pops back up to 5000 like it should but then drops right back down to 0. The left bonus unit does as it should and kicks up to 5000 and stays there. Any ideas of what could be going on?
snyper2099, I did a search on here Pinside for Grand Prix bonus unit and got one result which is the one I started. I have worked on 3 other Grand Prix in the past and had no issues with any of the bonus units.
Quoted from pinballman3:the right Bonus unit will drop back to 0 then it pops back up to 5000 like it should but then drops right back down to 0.
Let's assume that it's just receiving too many reset pulses:
Grand Prix R Bonus reset (resized).jpg
Since the Left Bonus Reset is working properly we can eliminate the Outhole relay and Reset relay switches at the top. I'd start by examining the two switches in red to make sure they're opening and closing as expected.
/Mark
Quoted from pinballman3:snyper2099, I did a search on here Pinside for Grand Prix bonus unit and got one result which is the one I started. I have worked on 3 other Grand Prix in the past and had no issues with any of the bonus units.
Lol, every single one that I’ve ever owned or played had bonus problems.
I figured i would jump on this thread as i am having a nagging bonus issue as well..... the left side works at it should....step up twice or 3 times depending on the setting chosen for top hole but the right side will only step up once regardless of setting. Now it looks like it gets stepped up by 3 c but this controls both L & R step up at same time decided by switch on change relay. Any help would be great.
The Left and Right Bonus Unit Step Up solenoids are driven by the Left and Right Advance relays. If you watch the Left Advance relay or attach a bulb tester to it you should see it activate 2 or 3 times (depending on your setting) when the left advance is lit and the top hole switch is closed. Compare that to what happens when the right advance is lit and the top hole switch is closed. Does the Right Advance relay behave the same way? Or does it pulse once and maybe stay active longer?
Quoted from snyper2099:Lol, every single one that I’ve ever owned or played had bonus problems.
You can come play mine. Works just fine.
Actually i got it working....here i thought the issue was on the bottom side but ended up being a closed switch on the right side bonus switch under right plastic. I had gone through the top side switches and adjusted when it first showed up but had forgotten one of the other guys changed to colour rubbers and i didnt even think to regap switches after that.
That even fixed a issue with right spinner not counting the same bonus as the left spinner with same amount of spins and here i was cursing those spinner relays and couldnt find any issues. Oh well every relay and units have all been gone through and cleaned/gapped now so should be good for many years.
Gotta love working on EM's
Quoted from MarkG:Compare that to what happens when the right advance is lit and the top hole switch is closed. Does the Right Advance relay behave the same way? Or does it pulse once and maybe stay active longer?
To answer that question it was just pulsing the right once quickly
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