Atari Centipede lands in the forest, audio repair

Centipede audio fix

I bought Matt C’s Centipede from him! Of the classic arcade titles, I think Donkey Kong and Centipede are my #1’s. They’re the games I remember playing as a little kid the most. Both games have cool sounds for the time and were good looking machines. The Centipede machine was close to solid, the big thing missing was sound. Matt had taken a shot at it, but never finished.

I bought a cap kit from my friend Buffett, to recap the G07 monitor while I was at it. Compared to the other monitors I’ve been dealing with recently like Sanwa 29E31S and Wells Gardner K9200 the G07 was a breeze.

On to the sound issue. First thing was fuses were blowing on the AR2 board which is a power supply / audio amp combined. So I needed to tackle this. Nothing looked out of place, everything seemed okay. Threw it in with a new fuse and it blew. I then tried it again and rapidly removed power and felt components. One of the caps was very warm, which seemed odd. I looked at it closer and one of them was installed backwards. Matt had recapped it, but looking at the board everything was right. But two caps were configured in a way that seemed odd circuit wise to me. I pulled up pics of the PCB and sure enough one was backwards based on pictures. But the board has a + screened right in between them both with no -, I can see where this error came from.

Put it back in. Fired it up !!! Oh yea, annnnnnnnnnd. No audio.

Someone had installed a home brew hack to move the volume potentiometer onto the front with a small hole where the sound can be adjusted without opening the cabinet. I decided to split the problem in half, and fed the audio from there to an external speaker. Got sound. So it’s the potentiometer! So I checked sound after it and… it still worked. So it wasn’t that. Huh? Pulled the speaker and one of the copper braided leads going to the speaker was fully missing. Just totally gone. Ordered a new speaker, and a new track ball. Sound was back! And track ball was solid. And it’s now in the home lineup and won’t be leaving!

Thanks Buffett and Matt !!!

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