(Topic ID: 76716)

'Special' problem on King of Diamonds

By heatwave

5 years ago

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  • 7 posts
  • 2 Pinsiders participating
  • Latest reply 5 years ago by DirtFlipper
  • Topic is favorited by 3 Pinsiders


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#1 5 years ago

I've had a '67 KOD for a few years that has played great and no issues with the scoring/awarding of specials. Suddenly a few weeks ago, the game stopped lighting/awarding specials for either the 2-9 or 2-Ace sequence.

I switched to 3-ball as a diagnostic and it awards for the 2-Ace special but not the 2-9. By the way, all the relays in the head are tripping as they should.

Here is what I have checked so far (with no solution):

- Visually inspected and lightly tugged wires on the 3-5 ball jones plug. They all seem OK
- Inspected the playfield to cabinet and cabinet to back box jones plugs. They all seem OK
- Inspected the 2-9 (YB) and Sequence Complete (ZB) relays in the cabinet. They all seem OK and will 'force-fire' when jumped from another coil (I used the 50pt coil). When triggered in this manner, the specials 'work'.

I have schematics although I will admit to being not that great at tracing on them.

Would appreciate any and all input - I'm pretty stumped. I keep the game in good shape although I have not played it as much lately. Live in the St Louis suburbs if anyone wants to check it out and play some other nice EM's! (Quick Draw, Heat Wave and Nags).

Thanks - Greg

#2 5 years ago

Since you say the game stopped lighting the special, that might be a simpler path to debug first. The Right (and Left) 'Special When Lit' lights are controlled by switches on the 'YB' relay and the Alternating relay ('A):


I've highlighted in yellow the logic path. When the game is set on 5-ball, the Right 'Special' light should be on when the Alternating relay is off (switch is normally closed), but the 'YB' relay is engaged (closing the switch there).

The 'YB' relay is the 2-9 sequence relay. So if that relay is not tripping after completing the sequence, then that suggests there's one or more switches not making good contact among the 2-9 relays.

So which path to pursue depends on whether 'YB' is activating when 2-9 are completed.

Since the game had been working, but sat un-played for awhile, then a possible scenario is that one or more switches in the 2-9 relay switch stacks simply oxidized, preventing good contact (even though they are closing). Cleaning the switch contacts would be the remedy (e.g., burnish with a flexstone). There's also a normally closed switch on 'YB' in series with the 2-9 switches that needs to have good contact.

If the game is set on 3-ball, then that will just circumvent the Alternating relay, and light both the Right and the Left specials when 'YB' is engaged.

The first question then is whether 'YB' trips when 2 through 9 are completed.

#3 5 years ago

Dirt Flipper -

Thanks for the input.

Right now the YB relay does NOT trip when 2-9 is completed (in either 3 or 5 ball). I can trigger it by jumping from another coil (I used the 50 pt coil) and then the specials light as they should.

I checked the normally closed switch on YB but I will check/clean again and also clean all the switches on the 2-9 relays in the head.

Will report back - thanks again, this is a stumper to me.

PS - also seems odd that the 2-Ace special works fine on 3-ball but NOT on 5-ball.

#4 5 years ago

OK, so if YB is not tripping on its own, then it's likely an oxidized switch contact on one or more of the 2-9 relays (and/or possibly the NC switch on YB). So even though they may 'look' like they're closing, it's amazing what some oxidation will do to mess stuff up.

On 5-ball, the 2-9 relays AND the 10-A relays need to all trip (and switches close) to activate the Sequence Completed relay ('ZB') (plus a NC switch on ZB).

On 3-ball, only the 10-A relays need to trip to activate ZB, and then YB is activated separately by having 2-9 trip.

So I think that's still likely consistent with a dirty contact among the 2-9 relays.


#5 5 years ago

You could further isolate which one(s) it is by jumpering from each successive 2-9 relay to YB. So if you jumper from say, 9B to YB, and it fails, then it's the NC switch on YB. If it works, then jumper from 8B to YB. Keep moving along until it fails, and then it's the previous one at fault.

#6 5 years ago

DirtFlipper -


I flexstoned all of the contacts on the 2-9 relays. Plus while doing this I noticed a piece of a flattened rivet on the 'actuator' arm (next to the yellow nylon roller) that when tripped was making contact with the switch stack on the #5 relay. Don't know if that was an issue but I fixed that as well.

Now works perfectly on both 3-ball and 5-ball.

Thanks so much for the help. I can usually identify and fix 90% of my issues but really appreciate the input on the other 10%!

Greg -

PS - really nice collection you have. I have a Nags as well and used to have an Abra Ca Dabra and Jacks Open. My issue is space.

#7 5 years ago

Excellent, nice to hear you were able to resolve it. Now, just keep playing it regularly so the contacts don't oxidize again.

Space is always the challenge. Wish I could keep them all!

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