Noise from power supply

[ersk3]

Hello


I have a noise from the power supply in my S+ "double diamond". Is it posible to fix? Is it a common problem?


Best regards Erik

[rokgpsman]

What does the noise sound like, is it possibly a fan noise? Does your machine operate correctly, any differences you notice while the noise is happening?

[ersk3]

The noise is 23Hz and loud. I have disconected everything from the power supply and it still makes the same noise. I gues it's broken? The machine operates correctly.

[slots4home]

Could not pm you

My email is 1@slots4home.com if you need one

[cowboygames]

If it's not having an overall adverse effect on operation it could be a cap going bad or the transformer "singing". You can look at the caps to see if anything looks bloated or if you suspect the transformer, try wedging something underneath it like a toothpick or whatever. We used to see occassionally where the distance between the transformer and the board would cause a harmonic resonance. Not on slot machine boards, because I wasn't working on them back then, but tv, amp, radio and whatever power supplies. Somewhere to start anyway...

[rokgpsman]

The noise is 23Hz and loud. I have disconected everything from the power supply and it still makes the same noise. I gues it's broken? The machine operates correctly.

23 Hz?  That's a very low freq, not sure my old ears could hear that low. Sound levels that low are often felt more than heard, like the deep bass sounds in a movie. Did you mean 23 Khz instead?  Anyway, you could take the cover off the power supply and inspect it, like cowboygames said there might be a part that is loosely mounted or a shield has come off, you might see something that is causing the noise. If careful you can take an insulated tool or a plastic wand and press against parts while it is making the noise to isolate where the noise is coming from. Don't press or touch anything in there with your bare finger, even if power supply switch is turned off, unless you are sure what you are doing. But pressing on stuff with an insulated tool is ok.

[ersk3]

23Hz must was worng, about 200hz is correct. I have pressed against the power supply and the noise changes. I have also measured the secondary side, and the readings seems quite a bit of. The voltage on the primary side looks fine, so it looks like the transformer is broken.

[ersk3]

I wonder if it's posible to replace the transformer with this one (see link below). My output gives me 240VAC, so my best guess is that it should work. Any feedback?



http://www.ebay.com/itm/Electric-Output-AC-6-3V-24V-36V-110V-Voltage-Control-Transformer-/310570256078?hash=item484f6e06ce

[ersk3]

Here is the old trafo

[rokgpsman]

I wonder if it's posible to replace the transformer with this one (see link below). My output gives me 240VAC, so my best guess is that it should work. Any feedback?

http://www.ebay.com/itm/Electric-Output-AC-6-3V-24V-36V-110V-Voltage-Control-Transformer-/310570256078?hash=item484f6e06ce

I don't think that ebay transformer is a suitable replacement.

That transformer you linked to has a secondary voltage of 6.3 vac on one of its outputs, your machine transformer drawing says it wants 7.0 vac. Not a huge difference but still not correct. I think that voltage is probably for button lighting, if so they would be somewhat dimmer. But it might also be used for something else. Also, on transformers you have to worry about the power rating of each secondary output. It isn't mentioned in the ebay xfmr auction that I saw. The stuff in your machine connected to the secondary windings will want to draw a certain amount of electrical current, some amount of amps. The replacement xfmr will need to be able to provide these amps, there is usually a rating on each secondary that says something like "24vac at 4.5 amps". This rating is shown in the IGT drawing you posted but I didn't see any mention of secondary power ratings in the ebay auction. The part number for the transformer in the ebay ad is "BK-100VA".  That makes me think the overall power rating on the transformer is 100 volt/amps. But your IGT transformer is rated at about 230 volt/amps (115x.75 + 24x4.5 + 7x5 = 229.25). The ebay transformer is not powerful enough.

Your xfmr doesn't show any sign of leakage or meltdown or burned. And your machine is working ok so it would seem the power supply voltages are ok. When you measured the secondary outputs did you get 115v, 24v and 7v, all are AC voltages? You said it measured "quite a bit off". But this is the main power transformer and your machine is working ok other than the noise, so how can the voltages be way wrong? When you measure the output voltages you need to put both meter leads on the secondary terminals, not have one lead connected to chassis ground like you might do with dc voltage measurements. [sorry if you already know this, just want to make sure since I don't know your experience level]

The xfmr is constructed of many thin metal plates, they are held together with a long screw going thru each corner. Might want to make sure all 4 of these screw are tight. If loose the plates can vibrate and make a noise. Also look for loose mounting of the xfmr to the machine chassis. I'm not sure you have an electrical problem, could be something mechanical. Also, a xfmr can hum loudly if something connected to it is drawing too much electrical current from the secondary winding, but you said the noise occurs even with everything disconnected from all the xfmr secondary outputs, right?

If you want to proceed and replace the transformer I'd first try to find the exact replacement. The folks that deal with slot machine parts can probably provide one. They don't go bad very often, so anyone that has parted out a machine would have them. Look for a tag with the part number somewhere on the transformer. Or if you have the manual for your machine the p/n might be listed in it. Lastly, someone here might know what p/n to use and where to get a replacement.

 

[ersk3]

Problem solved :-)


I found out that the wiring diagram I posted was not correct for my IGT machine. I took out the transformer from another early IGT S+ machine I got, and it was the same readings from the secondary side. I think they might have used the same transformers in the early S+ machines as they used in the S slot. I took on some ventilation tape on the sides of the transformer facing the wall and bottom, and it calmed down the vibrations.

[rokgpsman]

Problem solved :-)


I found out that the wiring diagram I posted was not correct for my IGT maschine. I took out the transformer from another early IGT S+ mashine I got, and it was the same readings from the secondary side. I think they might have used the same transformers in the early S+ machines as they used in the S slot. I took on some ventilation tape on the sides of the transformer fasing the wall and botom, and it calmed down the vibrations.

That's good news, can you post a photo of your fix so someone else with a similar problem will know what might help?  Thanks!

[ersk3]

It took me some time, but here are some photos

[Cashen87]

Hello. I have same issue on my machine. When I power up the machine then its comming a noise from the transformer

[shortrackskater]

Have you read and  tried all the steps that are in this thread, prior to its being resolved?

[Cashen87]

Yes

[shortrackskater]

Ok - Please start a NEW topic on this, and describe the problem. I want to keep this separate as this particular problem is resolved. Also, please note that you read this thread and tried the solutions from this thread. Thank you - moderator.