(Topic ID: 150548)

TECH: Bally Early SS switch issue

By drscottsmith

8 years ago



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#1 8 years ago

Ok - another quirk that has me completely stumped - probably with the simplest of answers. This Star Trek has an alltek board in it.

When the game starts (or in any test mode) the lower middle bumper pulls in and vibrates. Sometimes it will rapid fire. Also, usually on each initial pulse of the coil, the right bumper fires as well, but does not hold down...neither "lock" on as if the transistor is fried, just pulse rapidly.

Here's the weird part - if i CLOSE the contacts on the bumper spoon switch, the coil releases and all is well. Both other bumper coils work fine. When I let the switch open, it immediately starts the behavior again. Almost behaves exactly opposite from what it is supposed to do.

From what I can tell the wiring is good, but maybe I am missing something.

Thanks all -

-scott

#2 8 years ago

If it has a disk capacitor on the spoon switch (looks like a penny with legs) try lifting one lead.

#3 8 years ago

Cap is my guess too. It's causing spurious switch closures and the MPU is rapid firing the pop bumper. By holding the switch closed you are shorting across the cap, effectively removing it from the circuit. The bumper will fire once, then the MPU will ignore the switch until it opens again.

#4 8 years ago

Makes perfect sense and it does have a cap. Will try that and report.

Thanks!

-scott

#5 8 years ago

That was it! Thanks all!

#6 8 years ago

The clipped cap is good for now, but be sure to replace it for max performance.

#7 8 years ago

One thing that annoys me is having to behind the last guy(s) and unsolder the wound up cap leads that were snipped off. I've seen up to three sets! I cringe when someone says "clip the lead." It's easier to remove the twisted lead if you have excess lead to grab onto with the hemos. Just a personal rant for your enjoyment....

#8 8 years ago
Quoted from cody_chunn:

One thing that annoys me is having to behind the last guy(s) and unsolder the wound up cap leads that were snipped off.

Pic needed.

#9 8 years ago
Quoted from cody_chunn:

One thing that annoys me is having to behind the last guy(s) and unsolder the wound up cap leads that were snipped off. I've seen up to three sets! I cringe when someone says "clip the lead." It's easier to remove the twisted lead if you have excess lead to grab onto with the hemos. Just a personal rant for your enjoyment....

^TRUE DAT^ C'mon people, clean off all your old crap.

#10 8 years ago

Will do - thanks again all!

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