(Topic ID: 231729)

Sing Along - Electrical Issue


By schwism

10 months ago



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  • 19 posts
  • 4 Pinsiders participating
  • Latest reply 9 months ago by schwism
  • Topic is favorited by 1 Pinsider

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Sing Along O relay 2 (resized).jpg
311497EC-6E61-42DE-B557-234CF9D66942 (resized).jpeg
Sing Along O relay (resized).jpg
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Sing Along power rails (resized).jpg
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96BCCEC5-AD90-4D03-9B04-888843CE8A2C (resized).jpeg

#1 10 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?

8D5393BF-0603-4CEE-8CD4-45858A941079 (resized).jpeg96BCCEC5-AD90-4D03-9B04-888843CE8A2C (resized).jpeg
#2 10 months ago
Quoted from schwism:

Checked with a DMM and it gets only a fraction of voltage it normally gets.

What voltage does it get? Is it ~6VAC for the lights, or something else?
Sing Along power rails (resized).jpg
Before the ball is served, or after the game has ended and you still have power on the playfield, what voltages do you measure between the black wire on the left and the 4 points shown on the right?

/Mark

#3 10 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.

F62C8EB4-9644-4E47-BEC3-1DEE138098DC (resized).jpeg
#4 10 months ago
Quoted from schwism:

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

Where exactly are you measuring AC voltage? Maybe show us on the schematic. None of those values are anything I'd expect. The 29 volts you measured between the 25 volt rails is more like it. If you remove the two fuses in the 6 volt/GI circuit do you still get those low voltage readings?

#5 10 months ago
Quoted from MarkG:

Where exactly are you measuring AC voltage? Maybe show us on the schematic. None of those values are anything I'd expect. The 29 volts you measured between the 25 volt rails is more like it. If you remove the two fuses in the 6 volt/GI circuit do you still get those low voltage readings?

29v is the 24v rail these days, or maybe high tap

#6 10 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.

#7 10 months ago
Quoted from schwism:

I measured the input to the O ball return relay. It gets 29v at all times.

Is the O relay active at all times? If there are 29 volts between its solder lugs the coil is getting power and should be firing:
Sing Along O relay (resized).jpg
Are you sure you're measuring the voltage between the black wire and the yellow wire? If that's the case either the Outhole switch or the holder switch on the O relay is stuck closed.

As for the low voltage on the other relays, notice the Zero Position Ball Cont Unit switch shown above. Are all of the relays that show a low voltage above this switch on the schematic? This switch is intended to cut power to most of the game when there are no balls left. It could be that your switch is mangled so that it shorts somehow when it should be open. Or maybe the fish paper insulation on the switch, or the plastic sleeve on the pin on the stepper gear is worn and there may be a high resistance path through even in the zero position. If that's the case the switch and/or the pin might get warm if left on long enough. You could also shut off the power and measure the resistance across that switch in the zero and other positions.

#8 10 months ago

Check the actuator switch on the SB relay. It should be in closed position till tripped.

Easiest hope-make sure that bank is locked correctly into position w/wing nuts. If not it can wreak havoc also.

Very tricky switch to check and adjust. I always test continuity to make sure working correctly.(POWER OFF)Remember when working on that bank when you flip it up to adjust switch(s)!gravity may come into play when latching back in place.

Make sure switch stack screws are tight. If not, tighten the one closest to the blade first. Tough switch to see and adjust. Clean contacts. If switch needs adjustment, adjust the short blade. If somebody had messed with switch prior and bent the long blade then yes, you may have to adjust it. When adjusting with blade bender, keep bender as close to switch stack. Check continuity in closed position and open position. Continuity when closed, no continuity when open.

Hope this maybe of some help if in fact it is the SB relay switch.

#9 10 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!

#10 10 months ago
Quoted from schwism:

I’ll take another look at the ball count unit but I don’t see anything strange there.

Shorts are often hidden from view so only a meter can show conclusively whether or not they're there.

Quoted from schwism:

is the proper way to measure from the black wire at the transformer and the nonblack lug on the coil?

If you're measuring the AC voltage across a coil you just need to carefully touch or clip your meter probes to the two coil solder lugs. In the case of the O relay one lug is soldered to the common black power rail that probably goes back to the transformer. The other lug is soldered to a yellow wire that goes to a holder switch on the O relay and to another switch on the score motor. You could in theory measure the same voltage between the transformer and the score motor switch for example, but including all that extra circuitry is unnecessary and may introduce more uncertainty into the problem.

Another way to test if a coil is getting power is to use a light tester as described at: https://pinside.com/pinball/forum/topic/em-pinball-circuits-basics-to-not-so-basic/page/2#post-3184715

#11 10 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 10 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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#13 10 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.

I came back here to correct.....CRAP YES open not closed. I apologize. Sorry for any confusion. I know it should have been open not closed at reset. Sorry it didn’t help.

#14 10 months ago

I think I'm getting into the weeks a bit. There seems to be a lot of extra details that don't necessarily go together like the low voltage measurements. So for the moment lets dig into the O relay. If I understand correctly it fires even after the game ends. That means there must be a path somehow between the red-white wire in the lower right corner, and the red wire in the upper right corner:
Sing Along O relay 2 (resized).jpg
When the game is in game over mode and the outhole switch still works, you should be able to slip a piece of folded paper between the contacts of any of the switches along the right side of the schematic (DS, XB, TB or SB) and be able to stop the O relay from firing. If that's not the case, which of those four do disable the O relay and which don't?
It sounds like you have a short but it's hard to tell if it's through a switch or through something else like the frame of the trip relay bank for example.

Added 10 months ago:

Should have started, "I think I'm getting into the weeds a bit."...

#15 10 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 9 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 9 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?

#18 9 months ago
Quoted from schwism:

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.

What playfield features were live? It would help if you put together a complete list. Then we can see what they have in common.

Quoted from schwism:

Since this issue came up after tinkering with the score motor it is possible something is shorting there.

What did you do to the score motor? Can you undo it or retrace your steps?

Quoted from schwism:

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?

I don't follow most of this. Since most things have two terminals you need to clarify which terminals you're referring to, preferably with wire color. "jumpering between the score motor and C" is too vague.

If you manually close either the C or U relays, they should lock on and start the score motor turning. They should relax when the score motor 2B switch opens right at the end of the score motor's 120 degree turn. Do they not do that?

#19 9 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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