Atari ASSAULT - game works, no sound

ZEN

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So I pick up an Assault today, game plays works great no sound, I check the power supply , good voltages, check the jamma harness, good there. I get static on the speaker that is adjustable with the rehostat knob on the test panel, static feedback gets louder and softer..., no change in static from the volume pot on the board. Pull the board, reset the voice chip, check schematics, no visible issues on the boards audio section... The static would indicate the amplifier is working yes? Not sure what else is there...other than a component shotgun..uugh. Anyone have any experiece with these or know where to start....thanks in advance everyone...
 
First thing I would do is try the board in a different JAMMA rig, just to be sure the problem isn't in the speaker, wiring, or rheostat. Also note that there is a volume control on the PCB too, as well as balance (not used in Assault since it's mono), bass, and treble.
 
Forgot to mention that I did test audio in test mode, no sound. As noted before, the pot on the board makes no change at all, I could not find any info if there are sound roms on this or not, I know its NAMCO System 2..

there are 2 ICs in the sound section..both soldered in....ill get a pic for you guys of the schematics..
 

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Sorry to be a pest as Im not too familiar with the advanced jamma stuff, but I cant see to find the sound rom in the set, also I assume the 6809 you speak of is right in the middle of the cpu board?
 
Sorry to be a pest as Im not too familiar with the advanced jamma stuff, but I cant see to find the sound rom in the set, also I assume the 6809 you speak of is right in the middle of the cpu board?

Sounds about right (I don't have a board here anymore to check). There's only one 6809, and its ROM should be right beside it. Probably labeled "SND0".
 
Found some 6809's on some baby pac videots that I have laying around, tried them, they did not work, one was no change , one was a slightly diff version of the 6809 and it wouldnt boot with that one, and I know its good, another klover offered to re-burn the rom for me... other than that, I can find any broken traces, the amplifier gets warm on the heatsink, so Ill try the other two controller chips on the audio section I guess, just looking at the schematics, not sure if they failed it would completely kill sound but I dont know....
 
An oscilloscope would be your friend in this situation. Without one, visiting a friend who has a jamma setup and a scope would be your best course of action.

Bill
 
An oscilloscope would be your friend in this situation. Without one, visiting a friend who has a jamma setup and a scope would be your best course of action.

Bill

+1

With audio problems the scope is your best friend. You can see the audio in a picture form and a pic is worth 1,000 words.
 
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