(Topic ID: 364634)

GTB Pop Bumper ON Circuit

By schudel5

13 days ago



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  • 2 Pinsiders participating
  • Latest reply 13 days ago by schudel5
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#1 13 days ago

So I've been troubleshooting an issue on a friend's 300. Sometimes the pop bumpers lock on. So looking at the schematic, I'm not sure if I understand what Gottlieb was trying to do here.

So the pop bumper spoon switches (yellow highlight) are both in parallel and energize the B relay. The B relay has two contacts to drive each pop bumper independently (blue and purple highlight). The B relay also is in the 10 point relay circuit, but also has another set of contacts going to a NC set of contacts labeled "on left pop bumper" and "on right pop bumper" (green highlight) in parallel that also energizes the B relay. This set of contacts is under the pop switch and opens when the rod/ring/yoke are down.

So after going through everything it ends up there's something whacky with that B contact ahead of the "on left and right pop bumper" switches. The B contact is open but sometimes the B relay locks on and the pops lock on. If I jiggle the wires to the B contact it'll release.

So what is the purpose of the green highlighted line? If I put a piece of paper in the B contact in the green line it still works fine and never locks on. I thought it was to keep the pop coil from locking on but apparently it doesn't do that. Not sure what the green highlighted circuit is supposed to accomplish.

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#2 13 days ago
Quoted from schudel5:

what is the purpose of the green highlighted line?

It makes sure the pop bumpers give the ball full power.

#3 13 days ago
Quoted from HowardR:

It makes sure the pop bumpers give the ball full power.

Ok. I guess I can see that now. Thanks for the explanation. Now I need to figure out the short around that particular B switch causing the lock on condition.

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