720 sound problem

Bodie

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My 720 has no sound except coinup (taco bell sound), also zero control from stick, anything jumping or crashing distorts slightly.
I have tested the harness, +5 is great, reversed speaker wires to verify speakers, and have continuity through the harness. In test mode I hear sounds and speech, but is garbled at the end of words.
I have tried three different LETA chips (may all be bad).
Buttons and coinup works fine.
Any Ideas will be appreciated.
Thanks!

Update : fixed sounds by replacing chip 6116 row 1 second from last chip on CPU PCB.

Update 2: fixed control, the plugs on the optic board had been reversed. I was getting good voltage so i switched them. Wala its works!

Any Ideas on the other problem?
 
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you might try replacing your dual coupler board. does the stick zero out in test mode?(im sure it dosent just asking?)

i would start with the dual coupler board. did you check your voltage at the coupler board?

cr
 
Are you refering to the optic board? I have not tested any voltages there. Not sure how to test that board. I can find a ground, then can I test each point on the 2 plug as positive?
Thanks!
 
yes dual optic board, check your voltage there if its below 5+ you might try turing up your voltage. my guess is your optic board is fried.


cr
 
If you happen to need new opto's, I have NOS ones that are used on 720 and other later Atari games. They are part# C020290.

Brian
 
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graphic problem

Anything jumping or crashing distorts slightly have went through all roms, and still have graphic glitch.

Any Ideas would be appreciated.
 
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