(Topic ID: 276622)

Newbie question- Buzzing in synch with alternating high/recent score display

By Bandit78

3 years ago



Topic Stats

  • 8 posts
  • 3 Pinsiders participating
  • Latest reply 3 years ago by barakandl
  • Topic is favorited by 1 Pinsider

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#1 3 years ago

I just had a KISS delivered yesterday (1st machine), during the move the machine has developed a buzzing/hum. The buzzing sound tone alternates between when the high score displays and when the recent score displays. The sound comes out of the speaker and the machine has all new boards and was not humming before being shipped. I did have to disconnect all the cables from the boards in order to get the backbox into the house. During power up/boot period there is no humming, only after booting and the scores alternate does the humming begin. Where should I look.

Nervous Newbie

#2 3 years ago

The sound board has two paths to ground, the normal ground for logic stuff and then 43v to 12v reg has an isolated ground return. When there is grounding problems you get noise out the speaker.

A lot of times people can resolve this by backing the sound board up off the grounded backbox mount. Either leave the screw loose or put an insulator in. But ultimately its usually a ground problem related to connectors. Check rectifier board, backbox ground braid is attached to cabinet, connectors.

In the -next generation 51 sound board bally does not ground the board against the mounting bracket. They have the copper pulled back away from the screw points. I have wondered if it is because the earlier generation can have the symptom you describe.

#3 3 years ago

The sound board is AS-2518-50 replacement, date July 2017, Rev C NVRAM.WEEBLY.COM if that helps

#4 3 years ago

Can't get a better person to help you with your problems!

#5 3 years ago

Absolutely..this is great!

#6 3 years ago

Bingo!!! Loosening the screws did it...THANKS!!!!!

#7 3 years ago

Spoke too soon...now there are no operating lights under the playfield..never touched the lamp driver board.......

#8 3 years ago

When the game is moved and the head comes off some connectors get cycled and could expose connector problems. Find the rectifier board, I think it is still in the bottom right side of the head in this game. The grounds all come back to this board (sound buzz) and the playfield lamps bus voltage and GI return go this board. Give it a good visual inspection for burnt looking connectors.

The always on lamps are "GI" and should read around 6.3V AC

The computer controlled lamps are "switched illumination" or "feature lamps" and around 6.3V DC. With a multimeter you can see if your lamp voltage is missing.

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