Williams Comet audio hum

I never did get rid of the hum in my Comet. Grounded everything, etc. I think it is a fairly common issue. I'll look forward to hearing a solution!
 
Well darn, does yours have volume issues? The knob that is supposed to control the volume in mine is useless. Does nothing and it's stuck on LOUD.
 
Well darn, does yours have volume issues? The knob that is supposed to control the volume in mine is useless. Does nothing and it's stuck on LOUD.

There are two volume controls, one in the head and one in the main body. THe one in the head controls balance of voice vs sound. Mess with that. If the main volume does nothing look to testing / replacing.
 
System 11s in general have a significant hum.

Comet is a System 9. But definitely make sure that you have good ground contact on all of your PCB's in your backbox. If you're missing screws securing the PCB then add them in.
 
Mine hums with the lights, like you can hear the attract sequences. It's kind of funny. :p Very quiet though. Doesn't bug me. With all the games on and people moving around (or even without) you can't even come close to hearing it, I just notice during late nights with the games on alone to fix something.
 
All I can say is wow! I capped my power supply in my Comet last night. Plugged the board back in today, turned it on, and thought well shit.. I didn't hear anything but silence. Thought oh well I killed that board. Started a game to play it and it sounds amazing! It's truly quiet as a mouse now! It was making all kinda hum sounds before. They would go in and out and some kept humming the entire time. I did every cap in the power supply along with reflowed all the connectors while I was there. Seems my flippers are much stronger as well. Always nice to work on a game and the results are better then expected! So yea cap those power supply's and do them all! There is a bunch on that board. For the record they all tested good as well on the bench with my cap tester!
 
It works for me everytime. Those electrolytic capacitors tend to dry out inside after 10 years or more. I buy fresh ones from Mouser that way I know they will last a long time.

Rodger Kilgore
 
All I can say is wow! I capped my power supply in my Comet last night. Plugged the board back in today, turned it on, and thought well shit.. I didn't hear anything but silence. Thought oh well I killed that board. Started a game to play it and it sounds amazing! It's truly quiet as a mouse now! It was making all kinda hum sounds before. They would go in and out and some kept humming the entire time. I did every cap in the power supply along with reflowed all the connectors while I was there. Seems my flippers are much stronger as well. Always nice to work on a game and the results are better then expected! So yea cap those power supply's and do them all! There is a bunch on that board. For the record they all tested good as well on the bench with my cap tester!

I take it you bought all the caps off of mouser or is there a cap kit available?
 
I take it you bought all the caps off of mouser or is there a cap kit available?

Yes I got them all from Mouser. I have 2 kits in fishing lure type plastic boxes I made for my monitors and pins that have most basic cap values. I keep a little mixed inventory of them both so between the 2 I can cap almost anything out there. I know a few of those caps are expensive from Mouser! I'm still blown away how silent this game became. It always had some type of hum or buzz going on. Great Plains has some kits for the games as well. https://www.greatplainselectronics.com/products.asp?cat=45
 
Fixed it!

So my hum was from the old volume knob. As soon as I replaced it the entire problem was fixed! It's called a potentiometer- 5K Ohm Rotary Linear. I got mine at actionpinball.com part #POT5K1. 5 min fix
 
Fixed hum!!!

So I replaced the volume knob inside the cabinet because it wasnt working properly, and it instantly fixed the hum! Got mine at actionpinball.com part #POT5K1 - Potentiometer 5k ohm rotary linear taper, 15mm shaft universal. Seems like the wire from it and main board pin connector could also b a culprit. Now, I can go from almost no volume at all to louder than ever b4!
 
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