Asteroids speaker hum

Shavenyak

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Is it common to have a loud hum from the speakers on this game? Mine's louder than the hum on my DK. Any way to reduce it?
 
It's not normal. You may have a bad connection (mine sometimes hummed until I re-pinned the edge connector). Or you may have a bad audio amplifier on the AR board.
 
While you are following the other suggestions, also check the audio connector on the AR. You might need to re-flow the solder joints. I've seen this cure the hum as well.

Bill
 
there should be a checklist of stuff for Asteroids hum.

i'd start with:

- cap/rebuild the AR; reflow any questionable solder. set voltage to +5 at the main PCB.
- check all resistors and diodes on the AR; i recently fixed a hum by replacing a bad diode.
- replace "big blue" capacitor.
- clean PCB edge connector.
- check molex connector pins. replace any suspect pins, especially on the edge connector molex.
- disconnect the marquee light, the monitor, and the coin door to eliminate them as suspects for bad grounds.
- recap the main PCB.

good luck!
 
there should be a checklist of stuff for Asteroids hum.

i'd start with:

- cap/rebuild the AR; reflow any questionable solder. set voltage to +5 at the main PCB.
- check all resistors and diodes on the AR; i recently fixed a hum by replacing a bad diode.
- replace "big blue" capacitor.
- clean PCB edge connector.
- check molex connector pins. replace any suspect pins, especially on the edge connector molex.
- disconnect the marquee light, the monitor, and the coin door to eliminate them as suspects for bad grounds.
- recap the main PCB.

good luck!

All good suggestions but if none of them work you might have one or both audio amp chips bad. Make sure you have the correct A/R board.
It's easy to test, I unplugged the edge connector from my asteroids board, also unplugged the monitor, turned the volume pot all the way up then powered up the game. With power to the A/R board find the 2 pins on the harness edge connector for the sound inputs 1 and 2 and take a bare wire in hand and touch to input 1. you should hear a loud audio hum like the input of a guitar amp. Then touch audio input 2 and you should hear the same sound. In my case one was loud and one was not. One of the Amps was bad so I replaced both. The audio amps are set up in a push pull configuration and if one amp is bad this causes an imbalance which induces the hum. That's what worked for me.
 
I took the liberty of re-ordering your list (roughly from easiest to most difficult) and adding amplifier replacment...

- clean PCB edge connector.
- disconnect the marquee light, the monitor, and the coin door to eliminate them as suspects for bad grounds.
- replace "big blue" capacitor.
- check molex connector pins. replace any suspect pins, especially on the edge connector molex.
- cap/rebuild the AR; reflow any questionable solder. set voltage to +5 at the main PCB.
- replace TDA2002 amplifer ICs on AR board (TDA2003 can be substituted)
- check all resistors and diodes on the AR; i recently fixed a hum by replacing a bad diode.
- recap the main PCB.
 
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