Centipede Sound

Pinster

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(Reposting this snippet from the General forum)

New vid owner of a nice Centipede. The sound isn't working.

I checked continuity on the leads to the volume control by the coin door, FINE. I tried tapping in with an external speaker, nothing. I tapped a bit here and there on the cab, and HEY - sound for a brief moment. What the heck! Okay, great sign ... well after tapping away and jiggling connectors I found that when the slam-switch is held in you get sound. Lot's of what sounds like a high-pitched whine, but it's definitely game sounds underneath. So now I'm real puzzled; slam switch off=NO SOUND, slam-switch depress=SOUND. Any ideas???

Any help greatly appreciated.

Brian
 
(Reposting this snippet from the General forum)

New vid owner of a nice Centipede. The sound isn't working.

I checked continuity on the leads to the volume control by the coin door, FINE. I tried tapping in with an external speaker, nothing. I tapped a bit here and there on the cab, and HEY - sound for a brief moment. What the heck! Okay, great sign ... well after tapping away and jiggling connectors I found that when the slam-switch is held in you get sound. Lot's of what sounds like a high-pitched whine, but it's definitely game sounds underneath. So now I'm real puzzled; slam switch off=NO SOUND, slam-switch depress=SOUND. Any ideas???

Any help greatly appreciated.

Brian

sound I cant help u with

off topic where in NJ are ya? I had to drive to MD for my centipede saw u got yours local.

Most of the sellers on ebay in NJ want outrageous prices for their machines. I always have to expand my search to neighboring states usually.
 
sound I cant help u with

off topic where in NJ are ya? I had to drive to MD for my centipede saw u got yours local.

Most of the sellers on ebay in NJ want outrageous prices for their machines. I always have to expand my search to neighboring states usually.

I'm in Oakland, work in Branchburg /Somerville where the Centipede was.
 
Maybe the ground is not making it to the volume pot? Check your connections to the volume pot and make sure the pot itself is working correctly. When you close the slam switch is it rebooting?
 
Maybe the ground is not making it to the volume pot? Check your connections to the volume pot and make sure the pot itself is working correctly. When you close the slam switch is it rebooting?

Tried bypassing the pot and also checked it out, all appears good. Very puzzled on the sound behavior. Anyone with a working spare AR-II to sell or lend to isolate the problem?

Thanks,

Brian
 
Tried bypassing the pot and also checked it out, all appears good. Very puzzled on the sound behavior. Anyone with a working spare AR-II to sell or lend to isolate the problem?

Thanks,

Brian

If you get sound when the slam switch is closed then the amplifier section of the AR-II is fine. Your missing the sounds from the game board. Theres a good chance that the IC at C3 is your problem. On some older games each sound was created by a small circuit. It could be that the slam tilt sound is one of those sounds and everything else comes from the IC (it doesnt look like it though). If that IC is only generating that sound then its either bad or the data paths to the IC are broken or damaged.

Are you HOLDING the slam switch shut to get sound or just closing it quickly and letting it go?
 
If you get sound when the slam switch is closed then the amplifier section of the AR-II is fine. Your missing the sounds from the game board. Theres a good chance that the IC at C3 is your problem. On some older games each sound was created by a small circuit. It could be that the slam tilt sound is one of those sounds and everything else comes from the IC (it doesnt look like it though). If that IC is only generating that sound then its either bad or the data paths to the IC are broken or damaged.

Are you HOLDING the slam switch shut to get sound or just closing it quickly and letting it go?

Yes, I have to hold the slam switch to get sound. But when I hold it in it does play all the game sounds, plus the whine from what I assume is the slam tilt sound.
 
Yes, I have to hold the slam switch to get sound. But when I hold it in it does play all the game sounds, plus the whine from what I assume is the slam tilt sound.

Thats odd. Still makes me think that its a board problem and probably with that IC I was talking about.
 
That HAS to be a board problem, the shot sound is distorted too. Theres an OpAmp at K10 but I dont see a mute curcuit or anything on it so its got to be the IC at C3. C3 is a large IC and is probably in a socket. Maybe try re-seating it and see if that clears things up.
 
That HAS to be a board problem, the shot sound is distorted too. Theres an OpAmp at K10 but I dont see a mute curcuit or anything on it so its got to be the IC at C3. C3 is a large IC and is probably in a socket. Maybe try re-seating it and see if that clears things up.

Thanks for all the help. I tried reseating c3 ... Unfortunately no luck.
 
Woooohoooo!!

Update: it's fixed!

Took a gamble and purchased the guts of another Centipede on the cheap, including untested CPU PCB and AR-II. Started swapping boards ... It was the AR-II. Everything works great. Played a few two-player games with the wife and had a blast.

This is our first vid. Shopping for more.

Brian
 
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