Color Classic - No audio

[gomez6211]

Hello all,

I recently purchased a color classic, but the sound doesn't seem to work. I connected the actual speaker to a waveform generator I have, so I know it works. I traced back the wires to the analog board, but could find nothing wrong with it. I tried connecting some headphones the port in the back, but no sound comes out of those either. I really want to get this thing working so I can perform the Mystic upgrade. I would appreciate any help y'all could offer.

 

[Bolle]

when you go mystic you swap in another mobo and that should bring the sound back hmm?

 

[tomlee59]

I'm sure you already checked the following, but just in case not...

1) Make sure you don't have the sound slider on minimum, and verify that you're not muting the thing.

2) IIRC, there is a coupling capacitor between the audio driver and the speaker. During your tracing, you undoubtedly encountered it. That capacitor has a habit of dying, so if you can't find anything wrong, just replace the cap and see what happens.

 

[Bolle]

but when the cap dies it should make all kind of weirdo sounds cause the cap is only for filtering, shouldn´t it?

 

[paws]

Don't you mean 'non audio'?

 

[tomlee59]

but when the cap dies it should make all kind of weirdo sounds cause the cap is only for filtering, shouldn´t it?

Normally, yes, but the cap I'm referring to in this case would be in series with the speaker, not a bypass across the power supply. If this cap dies, you get no (or very weak) sound. Now, having said that, I am not at all certain that there is such a cap in this model. I'd promised Stuart Bell to extract a schematic from an analog board he arranged to have delivered, but as with many of my projects, it's for some other day...

 

[TheNeil]

Have you checked for capacitor leakage on the motherboard?