Intermittent 100 point relay sticking Target Alpha

By Metropolis

1 week ago


  • 11 posts
  • 3 Pinsiders participating
  • Latest reply 3 days ago by Metropolis
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Target Alpha score control relays (resized).jpg

#1 7 days ago

My machine has been playing great for a couple months, now all of the sudden, about every third game or so if you hit a rollover or drop target it will just keep ringing up the hundreds until you shut the game off.

#2 7 days ago

It looks like all of the rollovers and drop targets fire one of the two Score Control relays (C or D) shown in the schematic below.

Either one of those relays will cause the score motor to start turning and award points. What may be happening in your case is that once fired, the C or D relay isn't being released. So the score motor awards points, sees that the relay is still closed so it awards more points, over and over. You can verify this by watching the C and D relays to see if they ever release once activated.
Target Alpha score control relays (resized).jpg

The one switch that should release both the C and D relays is on the score motor at position 2B, circled in red above. If that switch doesn't open you'll get the behavior you're seeing.


#3 7 days ago

Ok, I checked that... it's opening well.

#4 7 days ago

It's really random, could be 3 or 5 or six games. Then all of the sudden in the middle of a game, hit a rollover or a drop target and it happens.

#5 7 days ago
Quoted from Metropolis:

Ok, I checked that... it's opening well.

It's not just the switch. It could be bent solder tabs, bare wire, solder blobs or anything else that could short across the switch.
What about the C and D relays? Are either of them active when you have the problem?

#6 6 days ago

Are the screws tight on the C and D switch stacks? and each has a M/B sw. that should be checked closely.

#7 6 days ago

Hopefully I got this, more games will tell as it's an intermittent problem...I cleaned tightened and adjusted 2b and c and d first it got better but would show up again. The fact that it got better showed me this is the area of the I went back twice so far tweeking... thanks for helping...will post back in a few days when I know for sure the problem is resolved.

#8 5 days ago

Check for floating contacts by crimping the switches involved. I had that problem on either C or D.

#9 5 days ago

So I got to around twelve games in and it did it again, I gave the c and d a crimp... I'll try to play more than twelve games tonight and see...

#10 4 days ago

Made it to 12 games and it happened again, going to take the 2b switch stack off the score motor...go over it really good...if that doesn't work, I wonder if a wire may be suspect. I'll try to jumper back to the relays and see if it goes away.

#11 3 days ago

It's been a couple days and it's been playing great now so I'm going to mark this as resolved. Thank you so much for the help!

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