Thanks in advance for a little help with sound buzzing. I get a pretty loud hum as the pin cycles through the lights in between games. Since I need to pull the Sys 9 board and replace a power transistor for a pop bumper, I was going to replace several of the radial capacitors on the lower right of the board (C2,5,7,24,53). I know old caps can be one source of the problem.

But I've since discovered that the culprit for about 95% of the buzzing. It occurs when the pop bumper lights illuminate through the sequence. They had been replace by a previous owner with LED's (I think BriteCaps EVO). If I pull these lights out, it eliminates the 95% of the buzzing or humming.

So my question is, does this change my approach? Would different lights here fix the issue? Maybe someone can chime in that has these lights. I'll probably still go ahead and replace the caps, but might put that off since I don't have those on hand yet if the lights are the culprit.

Also if I unplug the sound board (Swemmer 147-4-19) the buzzing stops. Not sure if that adds anything, but thought I'd mention that also since that's where I started my troubleshooting.

Pop Bumper (resized).JPG

Is there an LED replacement that's better or is this typical of this style? Definitely could just take them out, but wondering if they are specifically the problem or just emphasizing another issue like the caps. I've gone through the grounds pretty well. The rest of lights are LED's and I get very little buzz but it's just these that seem to be the issue. If there's a better choice that folks have good luck with, I'll switch. Thanks, still learning.

Thanks. I'm gonna replace the caps this weekend since I'll have the board out. If the buzzing is still there, I definitely check those out and likely get some.

Thanks, yep, that's one of the first things I did after reading a little. And I really tried check to make sure everything was grounding good. Did find the braided ground cable from the bottom cabinet was no longer connected to the backing, so not all the grounds were common. Fixed that but didn't help the buzzing. I'll double check that stuff again though.

Thanks. Good info. I'll clean the contacts when I lift the board for my transistor repair. Yep, I fooled around tightening and lifting the sound board also to no avail. Honestly its not noticeable while playing, only when the game is sitting idle that you really hear it.

So what's the secret to removing the connectors from the Sys 9 board???? I can't get these things off. I tried inserting a little piece of plastic I made to lift the clips, but I can't get these things to budge. I'm afraid of wrecking the clips. I can see a few are already broken here and there. What's the technique or tool to use? I wasn't expecting this to slow me down.

clip (resized).jpg

Thanks, that got it. It was an SOB but eventually got it moving. I was a little worried to keep at it at first since I wasn't sure the clips would release. A very tiny flat head under one side to give it a nudge helped.