Quoted from PogoFX:
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.[quoted image]
Those multi led super brite pop bumper boards always cause buzzing in my past experience. The lighting in my SS always causes some level of hum, much less with led because it draws much less current. My personal thought is resistance in the old dirty wire harness connectors. When I first got my space shuttle the speaker hum was awful and would oscillate with the attract mode lighting sequence. After cleaning and tightening all the wire harnesses it seemed to get rid of the hum almost completely. After about 6 months to a year the hum returned somewhat but at a much more tolerable level. Cleaning the pins and connectors with contact cleaner and tightening the connectors on the wire harnesses seem to help dramatically. Monkeying around tightening and loosening and lifting the soundboard from the back box had no effect whatsoever