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No sound on Classic II even after recapping

jack

Well-known member
Hello 68k MLA folks,

I recently aquired a Classic II (actually a Performa 200...). When I first got it, no startup chime and vertical bars, the usual symptoms of leaky capacitors.

Cleaning the logic board allowed it to start and System 7 works great on it, but there was no sound. I connected my cell-phone using alagator clips to the speaker and was able to play music on it (at low volume), so I figure the speaker was ok. Figured some of the caps needed replacing, so I went and replaced all the caps on the logic board.

Even after replacing all the capacitors on the logic board, I still can't get any sound to work. Any ideas what to check next?

Thanks.

 

Macdrone

Well-known member
the physical speaker.  If you do a search there is already a thread somewhere on this.  In fact it was talked about around 2 weeks ago again.  I pulled one from an LC and drilled out the rivets and put in a newer known working speaker and all was well.

 

Macdrone

Well-known member
Not sure then, might still have cap goo under the sound chip, or a bad trace.  Does the sound port on the back work?

 

jack

Well-known member
Not sure then, might still have cap goo under the sound chip, or a bad trace.  Does the sound port on the back work?
When I plugged in a pair of headphones, I was able to get the system sounds out of the sound port, although very faintly. Was this port designed for a pair of amplified speakers (as opposed to headphones)? If so, that could be why the sound was so quiet.

Anyway, this was an improvement over before I had recapped the board. When I originally did it, there was no sound even out of the sound out port.

do you have pics of your board?
classicii_newcaps.jpg.4138ec631f2246a972d96a33547e795d.jpg


There she is...

It's much cleaner than when I got this thing (used to belong to a heavy smoker. there was about an inch of black grime on it when I got it.)

 

jack

Well-known member
Cap goo. Faint sound is bad caps usually, but goo I think could be another possibility?
Poured quite a bit of rubbing alcohol on the board, aiming to get as much as I could underneath the DFAC. After letting that dry, was not able to change the result of the audio.

Which pins on the connector to the analog board are for the speaker. If I could block those pins from connecting, I could narrow down the problem of the faint audio through the sound out jack to just the logic board (or confirm that the analog board is interfering).

 
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jack

Well-known member
So this logic board has been through massive amounts of cleaning now... I doubt there's any cap goo anywhere left.

I did notice that I must have accidentally lifted a solder pad on C5 when I recapped it. I traced the positive terminal of that capacitor to a spot on the rear of the logic board it connected to and added in some bodge wire. Didn't help any.

Anyone have any other ideas? If not, I've got another Classic II coming in the mail eventually that I can swap out plenty of parts with to see if I can figure out the issue.

 
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