John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

While I'm still working monitor issues, one consistent issue is that my Pacman has a loud hum coming from the speaker. I haven't been able to hear any other game sounds yet at all. I've been doing some searching but haven't really found any solid suggestions.

I have replaced a couple of sound-related ic's on the pcb (and will probably replace the amp etc) and have a pcb recap kit on the way as well. Are there any go-to tests that I should focus on? Something specific I should look at first that's maybe more obvious to those more experienced with this issue?

Thanks!!!
Brian


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Make sure it's not the edge connector. Wiggle it while the game is on to see if you can get it to go away. Mine was humming bad and it was the edge connector. Bad connection

What John said. He helped me diagnose that on my Ms. Pac too. It was discovered that moving the wires on the edge connector helped the hum come and go. I even had the hum bar going across the screen.  This should help do the trick if it gets to that extreme:

http://www.therealbobroberts.net/hum.html

That edge connector seems to cause a lot of problems. My Mrs. Pacman won't boot sometimes but if I wiggle the edge connector I can get it to boot. I just need to change the darn thing and get it over with. Sounds like a good idea for any Pacman or Mrs. Pacman.

I just went through this twice this month on two diff pac machines.
on one, I installed a new power supply... went away .. hum bars gone.

on the other.. I swapped it to a switcher and changed the edge connector..
had a loud ass hum before.. now silent with no hum bars.