Mystic
Bally, 1980Gonna need a new transformer for my Mystic. Is that something I get at my local electronics warehouse or would it be a specialty item from a pinball supplier?
Any tips on safely removing and replacing the transformer without getting zapped?
Quoted from undrdog:Gonna need a new transformer for my Mystic. Is that something I get at my local electronics warehouse or would it be a specialty item from a pinball supplier?
Nope. It's a specialty transformer. Most pinball places aren't going to carry it any longer. Marco has been out of stock on the E-122-125 forever. https://www.marcospecialties.com/pinball-parts/E-122-125 Best bet is going to be to keep an eye out on Ebay or PS marketplace for a used one.
Quoted from undrdog:Any tips on safely removing and replacing the transformer without getting zapped?
Obviously, don't change it while its plugged in.
Quoted from undrdog:Gonna need a new transformer for my Mystic
Why do you say that? They rarely go bad. Usually when there are electrical issues, it's typically due to the rectifier board.
Quoted from undrdog:Is that something I get at my local electronics warehouse or would it be a specialty item from a pinball supplier?
Neither. They have not been remade. You would likely need to source a used one.
Quoted from undrdog:Any tips on safely removing and replacing the transformer without getting zapped?
Transformers don't retain a charge. Turn off the power, unplug the game, and disconnect the connectors and wires.
Prepare for some sticker shock. You used to be able to buy a used transformer assembly for $25 or so.... I'm told by a parts selling buddy that transformers are fetching big bucks these days.
Make sure it's bad first, of course, they actually rarely go bad.
Quoted from slochar:Prepare for some sticker shock. You used to be able to buy a used transformer assembly for $25 or so.... I'm told by a parts selling buddy that transformers are fetching big bucks these days.
They seem to go for around $125-$200 these days.
I always thought this was a good video.
The schematics will help you know what AC voltages you should have at the transformer itself.
-Mike
Quoted from ForceFlow:Why do you say that? They rarely go bad. Usually when there are electrical issues, it's typically due to the rectifier board.
The machine hums, intermittently. It is getting louder and more frequent. Sounds like it is coming from there.
The machine is in a building that is new to us. My back up power supply showed incoming voltages in the 137 range. Should be 110. Electrician confirmed the problem and had the power company come out. They put a new box on the pole for our block and now our incoming voltage is correct.
I thought that the high voltage coming into the building may have made any problem with the pinball worse.
My first impulse is to get it fixed. But, I could let it go until the bad part fails.
Humming from speakers,soundboard or transformer itself?
Speakers humming could be a bad ground. If the humming is in tune with the playfield lights it could be a ground loop.
Sound boards can give off an odd hum also indicating a bad ground or ground loop.
Replacing the very outdated capacitors is another idea to freshen things up and not have any leakage and get the signals smoothed out again.
I have seen transformers somehow loosen up and give off a hum from the plates.
If that is the issue it's as simple as unplugging the machine and tightening the bolts.
-Mike
Coming from the transformer. It’s not the speakers. Besides, it hums when the machine is up, but there is no game going. Mystic doesn’t make sound unless there is a game.
I'm onboard with the other comments regarding if it's really bad. A transformer can buzz when there's an excessive load on it. Are you able to pull some fuses on the output side of the transformer (to remove the load) and see if it still buzzes?
Are the bolts that hold the transformer assembly together tight? Loose laminations can cause buzzing. Not the screws that mount it, the ones that go through the metal plates.
Quoted from undrdog:Coming from the transformer.
Use to work on old yard lights at gas stations. The ballast would hum very loud when it was time to replace them. They were identical to the transformers in pinball machines.
Quoted from bssbllr:Use to work on old yard lights at gas stations. The ballast would hum very loud when it was time to replace them. They were identical to the transformers in pinball machines.
I'm not sure that I would equate the two things--they perform different functions, and a ballast has internal components that can fail. A transformer is just wound wire.
Another hobby that uses big power transformers is home audio. There could likely be someone in the Dallas area that is experienced rebuilding/rewinding power transformers. The audio transformers are very similar in build with all kinds of secondary outputs.
Quoted from twhtalm:Another hobby that uses big power transformers is home audio.
Wow! Great idea! There are two or three places around here that specialize in vintage audio repair.
Quoted from ForceFlow:I'm not sure that I would equate the two things--they perform different functions
A Transformer transforms amperage and voltages up and down.
A ballast supplies a stable power supply.
The ballast I used to work on for metal Halides and HPS where big with wound wire as well. When they went bad they would hum.
48395808-6048-4706-97C4-CF01F24C7769 (resized).jpegQuoted from undrdog:Wow! Great idea! There are two or three places around here that specialize in vintage audio repair.
Reach out and I'm sure any one of them could point you in the right direction. Be careful not to get hooked on high end home audio, there is no price ceiling.
If tightening the bolts that hold the metal plate core together doesn't minimise the hum, there is interesting info here about trying to rebuild the core:
https://pinside.com/pinball/forum/topic/transformer-refurbish-suggestions
See post #13 and related posts regarding isolating the plates.
Quoted from undrdog:I’ll try tightening the screws & see if that does it. Maybe I’ll get lucky. Stay tuned...
How did that work for you?
And, the lucky winner is... Skidave
Quoted from Skidave:Are the bolts that hold the transformer assembly together tight? Loose laminations can cause buzzing. Not the screws that mount it, the ones that go through the metal plates.
Tightened the the screws. Didn't get blown up. The machine has been on for about half an hour and there is no humming.
A big Thank You to everyone for all of your insights and suggestions. You folks are the greatest.
Awesome! I work on old audio gear (vacuum tube stuff) and build my own tube amps. It seems the old stuff never has vibrating laminations. New transformers sometimes vibrate because hardware is not as tight as it should...and it costs a ton!
Its starting to hum again. Would it offend the pinball gods if I put some locktite on the screws? Any reason not to?
The set screws on the right flipper keep having to be tightened, too. Any reason not to put locktite on it?
Quoted from undrdog:Its starting to hum again. Would it offend the pinball gods if I put some locktite on the screws? Any reason not to?
The set screws on the right flipper keep having to be tightened, too. Any reason not to put locktite on it?
Locktite on the transformer, sure. On the flipper.. no. Rebuild the flipper instead. If you locktite it, you will have a HELL of a time rebuilding it later.
Quoted from frunch:You really gotta tighten the hell out the set screws too. You may want to try a new pair of flipper bats if the problem still persists (or consider rebuilding, as above poster suggested)
The bats are quite old. Keeping the old one was supposed to allow me to tighten the set screws back into their accustomed groove, but its not working that well. Maybe I didn't find the groove, but I've tried three times now.
What started it all was the plastic bats needed to be replaced. The left flipper is fine. The right one gets loose.
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