Color classic headphone/speaker out weirdness

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Color classic headphone/speaker out weirdness

So I had to replace a bad Dfac2 chip on my color classic board to get any audio. When I plug a speaker or headphone set into the audio out I am expecting to get stereo audio out and the internal speaker to cut out.. But the internal speaker keeps playing audio and the audio out only plays audio via the left channel (left earphone). 

 

Is this normal behavior?

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Mono

According to the Apple Service Source manual for the Color Classic, it has monophonic audio only.

https://www.applerepairmanuals.com/the_manuals_are_in_here/Color_Classic.pdf

This is in contrast to the SE/30 which has stereo sound from the ASC (Apple Sound Chip).

I would expect that the audio out jack is of the TS type (tip, shield) rather than the stereo TRS type. You can look inside the jack or count the pins that attach it to the board.

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Thats some comfort however

Thats some comfort however what about the internal speaker not cutting out when a speaker cable is connected to audio out and they both play audio?

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normaled or not

To detect when a plug is inserted into an audio jack, the usual way is to use "normaled" connections, but it is possible to do it differently. I would try to use a TS (mono) plug, it might only be able to detect that kind.

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I will try with a mono plug

I will try with a mono plug and see what happens

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Thats a negative. I think the

Thats a negative. I think the next step is to replace the audio jack. But before I go to that length. Can someone with a Macintosh Color classic please test a pair of head phones on the audio out jack in back and see if they get audio for one, and if the internal speaker still plays audio or cuts out? Thanks

 

Edit: When I use the same headphones on the audio jack of my LC575 (arent they from the same era?) it works fine and in stereo and the internal speaker cuts out.

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replaced the jack, no change

replaced the jack, no change whatsoever. I am at a loss. Its not the audio jack

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Ok maybe I found something.so
Ok maybe I found something.so I found that pins 37 and 38 on U5 (DFAC2) are shorted (have continuity). Using magnification I can find no solder causing the short.Going by the schematic page 11, pins 37 and 38 goto the headphone jack.So the first photo shows what pins on the jack have continuity when no headphone is inserted.

 

And when the headphone jack is inserted the continuity on the jack changes to this: 

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