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Thread: Macintosh II Speaker and Audio Output Jack

  1. #1

    Default Macintosh II Speaker and Audio Output Jack

    Greetings All !!



    I finally finished restoring a Macintosh II logic board and all is working great. All except the internal speaker. I got zero audio from the speaker. The audio output jack works but only one channel ? I wasn't sure if this is a mono output or stereo output ? I thought I read online somewhere that it's a stereo output, but can't find that article anymore. Can someone let me know ? Also, if it is stereo, I believe I have a bad channel. Would like to know where the sound chip and DAC is located or anything else I can look at ? The jack tested fine as when there is no connector inserted, I get continuity to the speaker jack.



    Thanks !!

    MaCJaX

  2. #2

    Default

    I think the Mac LC line was the first to have stereo sound.

    Anyway, my Performa 475 has exactly the same issue: output jack works fine, but the internal speaker stays silent.

  3. #3

    Default

    Quote Originally Posted by Timo W. View Post
    I think the Mac LC line was the first to have stereo sound.

    Anyway, my Performa 475 has exactly the same issue: output jack works fine, but the internal speaker stays silent.

    It looks like there is 2 Apple Sound chips associated with this, right next to the speaker terminal. I am having problems figuring out which sound chip is for which side (left or right). It looks the right channel is also shared with the internal speaker. I have a few extra sound chips if you want one for your Performa. Let me know ..

  4. #4

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    Just an FYI for whoever has the same issue. I was able to fix. I had 2 issues. 1st issue was a bad trace from C5 (positive lead) to U14 pin 15. The other was a bad U15 IC. Fixed trace and replaced IC and she's working !! Thanks all !!

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