Speaker Humm problems.

[cwellsatl]

So this is my first post... I have 4 Pachislo machines that I bought at a coin op auction over ten years ago. I finally made room for some of them in my man cave. But one of them has a very annoying speaker hum to it. It is an IGT Popper King. Which I think is about a 1998 model. It only has a single speaker in it. I was thinking about replacing the speaker. But figured I would ask here to see if there is some thing else I could to figure out how to make the hum go away or minimize the sound.

Also looking for a door lock for it if anyone has a spare. It seems to be one of those that is welded to a bar. Which i don't have.

Thanks in advance

[luckydog]

try reversing the power cord in the outlet or maybe ground the transformer?

[stampeed valkyrie]

Also trace the wiring from the speaker to the source... does it come close or make contact with any power or higher voltage wires..
you may be able to quiet or remove the hum by separating them.

[cwellsatl]

try reversing the power cord in the outlet or maybe ground the transformer?

reversing the cord did not help. looks like there is a third poll on the transformer. So I'm guessing that is for a ground. And I can see where a ground was cut on the base plate. So I will give that a try. Thanks for your input.

[cwellsatl]

I pulled the speaker wire completely out where it could not touch anything. Still humms.

[mandoman]

reversing the cord did not help. looks like there is a third poll on the transformer. So I'm guessing that is for a ground. And I can see where a ground was cut on the base plate. So I will give that a try. Thanks for your input.

Careful connecting a ground wire to a transformer. The "third poll" could be a tap for a different voltage. The cut ground/green wire connected to your frame is common. That one you can connect to ground.

[stampeed valkyrie]

The hum is usually caused by an unshielded ground.
Could also be a bad or cheap Pot..

You can try taking the Pot out of the loop and see if that solves it.

[cwellsatl]

The hum is usually caused by an unshielded ground.
Could also be a bad or cheap Pot..

You can try taking the Pot out of the loop and see if that solves it.

Ok thanks for the reply. I am going to work on this over the weekend. Probably a ground issue. However I am not exactly sure what a "pot" is? Please forgive my ignorance.

[stampeed valkyrie]

Pot is shorthand for Potentiometer (sp?) or the volume control. Usually wired in series with the speaker.

[Wayne-Ooo]

Don't know if this Topic would be similar to your problem.

[cwellsatl]

Pot is shorthand for Potentiometer (sp?) or the volume control. Usually wired in series with the speaker.

So. I grounded the machine and did not fix the problem. So then I changed the speaker. still did not fix it. Finally I bought a Pot on ebay and wired it into the unit. If i turn the sound all the way up i hear the Humm still. But if i turn it down just a fraction the humm is unnoticeable. thanks for your input. Im in good shape now.

[stampeed valkyrie]

You might also be experiencing an issue called harmonic distortion.. This was very common with cheap and low end audio amplifiers, there are probably audiophiles on here that can chime in further..

Glad to see it working to your satisfaction.