(Topic ID: 231729)

Sing Along - Electrical Issue

By schwism

11 months ago

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  • 19 posts
  • 4 Pinsiders participating
  • Latest reply 10 months ago by schwism
  • Topic is favorited by 1 Pinsider


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Sing Along O relay 2 (resized).jpg
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Sing Along O relay (resized).jpg
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#1 11 months ago

Looking for suggestions for next steps. Game starts fine but at ball zero (before ball 1 is served) Playfield already has power. Flippers work and some scoring works. However, if a relay comes into play it only buzzes. Checked with a DMM and it gets only a fraction of voltage it normally gets. Once ball 1 is launched scoring is normal until end of game. After ball 5 drains normal game over comes up (XB triggers) but balls continue to be served. Scoring goes back to the way it was at ball zero. It appears Playfield somehow gets limited power from an unknown source. I’ve looked at all switches and am running out of ideas. Has anyone had this issue in the past?

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#3 11 months ago

Thanks Mark. On the relays it gets 1.5-2 volts. I get 11 when things are normal.

Hopefully I measured correctly. In the picture TB is at the top, then SB and XB. On XB I measured what is the fifth switch from the top in the picture, top level with red and blue wires. Got 29.4 volts regardless of switch being open or closed. Same on TB. SB is trickier but I seemed to get 29v here as well.

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#6 11 months ago

Thanks for bearing with me. I’m still learning. The lower voltage readings are the inputs for the relay coils. I measured relays C and P. I pulled the G.I. fuses and saw no difference. I measured the input to the O ball return relay. It gets 29v at all times. What would be a good place to get a better reading?

I’m struggling with the SB relay. This looks to be a make/break at 12I on the schematic. The second m/b appears to be at 15D and is not a factor. I see an N.C. switch at 10G that resets ball count and replays which looks fine. I still haven’t found the other N.C. switch. Since SB gets triggered at game start, controls new game stuff and then gets reset by the armature arm it should end up closed at ball zero,right?

Also, I blocked the DS switch at I14 which did cut off power to flippers, outhole and trough but still left power to the Playfield.

#9 11 months ago

Cash, are you sure the actuator switch should be closed? I checked for continuity on my King of Diamonds and it seems to be open. In any event having the switch closed at first doesn’t help. Checked it for continuity when in place and still having same issue. I did make sure bank is properly locked. As background, this issue crept up recently after things were working well. I was working on the machine trying to diagnose why the Y relay won’t hold. Most of my attention was on the score motor.

Mark, I’ll take another look at the ball count unit but I don’t see anything strange there. Re measurements I have a question—is the proper way to measure from the black wire at the transformer and the nonblack lug on the coil? If so I need to check things out some more.

Thanks to both of you for your help and patience. I’m learning a lot!

#11 11 months ago

I’ll take another look at the ball count unit.

Back to the O relay, it is not active at all times but only when it serves up another ball. I clipped the DMM leads to the two coil lugs and checked the voltage when the relay fired. The 29V is what I get when the relay serves up a new ball. This happens every time, even when XB or TB has tripped. When I try the same thing on other relays such as C and P I get the high/low readings I mentioned earlier.

Thanks for the link. I’ll check it out. There’s a wealth of info on the site but it takes a lot of digging to find the good stuff.

#12 11 months ago

Checked the ball count unit. Put leads on the black transformer and on each of the six lugs. Middle 2 each shows 29v when at ball zero and all switches are open. Middle two look to be the switch you mentioned above. Wires are red and red/white.

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#15 11 months ago

Cash, I’m confused about your reply since it just seem to be an excerpt from my post.

Mark, I’ll take a look either tonight or tomorrow. I did try blocking the DS switch when at ball zero. Flippers, ball trough and out hole were dead but other Playfield features were live but at reduced voltage. I’ll check XB and TB but given I have the issue at ball zero I’m not sure they are the factor. SB is trickier since it is make/break and I think should be closed except when game is resetting.

I’ve been wondering about the path just below SB. It looks like score motor switches are open which cuts power to a number of things. May see if they are truly open. Since this issue came up after tinkering with the score motor it is possible something is shorting there.

#16 11 months ago

I tried a number of things today. On DS I blocked the switch while at ball zero. There was no power to flippers, trough or ball return but there was still low voltage scoring. At balls 1 to 5 ball return did work but everything else was the same. Same at game over. I checked XB and switch was open but ball return etc was still active. I can jumper the switch and scoring goes back to normal. Same with TB.

It does sound like a short but I have a feeling it will be a long process to locate it.

#17 11 months ago

I decided to look at a different problem to see if it is a contributing factor.

The problem is that the C and U relays won’t hold. On the schematic in post 1 the area in question is around 5E. The slate wire from the score motor does not have continuity with C. It does between C and U. I tried jumpering between the score motor and C which does work but the score motor never stops running. I measured voltage during the score motor run and it never varied even though the switch opened.

It is possible the slate wire is shorting things?

#19 10 months ago

I finally figured it out. Slate wire from score motor to C was the culprit. Not only was it not showing continuity but it was shorting the score motor switch. Once I unsoldered it at the motor the short went away. Ran a new wire to C but kept slate wire connected there since it runs to U. This resolved the hold issue and even better this took care of the game over issue as well.

I’m still baffled why one wire caused all this but at least things are fine now. Thanks to everyone for their help. Hopefully someone can benefit from this in the future.

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