Centipede Sound issue

Kawydud

Member
Joined
Mar 13, 2010
Messages
970
Reaction score
10
Location
Strykersville, New York
I have an original centipede that I purchased that works great other than the sound. While playing the game it sounds like the speaker is blown, crackling sounds, not clear. I recapped the ARII board with a kit from Bob Roberts. Still same problem. The only that I can see that might be causing it is that I have 6 volts DC instead of 5. Not sure if the voltage can be reduced without a new power supply, still has the original. Would the 6 volts be causing my sound issues, or is 6 volts acceptable?

Thanks
 
6V is indead quite high. I've heard of Centipedes running up to 7V but that can't be good on the long run. The sense circuit causes this. I suggest a sense mod (like described here: http://www.stickycarpet.com/pinx/ar2mods.html). After that you can regulate the 5V manually. Check also the -5V and 12V because they feed directly into the lm324 which is often the cause for sound troubles on Centipedes.

cheers, prc
 
You need to turn down the 5v on the ARII using the pot at R8. Measure the voltage on the main board while adjusting the voltage on the ARII. If your ARII is rebuilt and your edge connectors are in good shape, I wouldn't do the "sense mod". There has been plenty written about it here, if you search you can get both sides to that story.
 
As mentioned, check the 12VDC and -5VDC rails.....these two voltages (only) feed one chip, the noted LM324. I'd also look at the audio amps...TDA2002. There's two of these on the A/R II board.

Also, 6VDC is way too high. There should be an adjustment pot on the A/R II board. Turn that sucker down.

Edward
 
Back
Top Bottom