Atari C-380 Video Pinball no sound

[wjalex4]

I have an Atari C-380 Video Pinball console.  The system seems to work fine, except there is no sound.  This unit has an internal speaker (does not use the TV for sound.)  I thought maybe I had a bad speaker, but tried another speaker and still no sound whatsoever... no static, no clicks, nothing.  I have checked for cold solder joints and such, but have not the problem.

 

Does anyone have any suggestions?  Thank you.

[Voxel]

Just to make it clear my response is speculation as I do not own one of these.

 

I'll assume you are providing the correct rated power the console requires.

 

I'll assume that you're using the RF out and say that my first point would be the tuning pot in the RF modulator.  I don't know if you need to pop the top off the modulator to locate it or if there is a hole to access it.

 

Next I'll assume you have a basic multimeter.

 

I would also work my way backward in the circuit from the speaker to the IC pin and check my next culprit which would be the audio capacitor, but as I don't know this console I'm not even sure if/where there may be a suspect capacitor and what type.

 

I would finally check the IC pin responsible, and see the voltage pulses when a signal is output (i.e. play the game and initiate collisions while checking the pin).  I would check it on the IC, and the socket pin its' in (you could just check the two for continuity).