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Thread: Apple IIgs with Quiet sound output.

  1. #11
    Join Date
    Jan 2012
    Location
    Connecticut, USA
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    Quote Originally Posted by cruff View Post
    The signal to the speaker goes through the headphone jack which disconnects it if a plug is inserted. If those contacts are oxidized or corroded, that would also reduce the signal to the speaker. You could test it by connecting the speaker between the audio ground (J17 pin 2) and the junction of SC6 (22 uF) and SR12 (220), bypassing the headphone jack.
    Cruff I took your advice and tested the speaker bypassing the headphone jack and noticed an immediate improvement. I used some small cleaning brushes from harbor freight (https://www.harborfreight.com/airbru...-pc-68155.html) to clean the headphone jack vigorously. Upon restarting the system as I had the volume at 100% It was quite loud and I noticed something as well; there was a bit of background noise with the volume at maximum. I lowered the volume down to stock setting and it was better but still a bit low. I cleaned a bit more and the volume is not acceptable at the stock level. I will followup with some deoxit as well.

    I would never have assumed the culprit was the seldom used headphone jack, thanks so much for pointing me in the right direction!
    Mick
    Last edited by VERAULT; January 2nd, 2020 at 10:56 AM.

  2. #12
    Join Date
    Dec 2012
    Location
    Colorado
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    Good news. The headphone jack is used as a switch to lower the drive level when a plug is inserted into the jack to avoid overdriving headphones. When there is no plug inserted, there are two internal contacts that bypass the attenuation components to drive the speaker at a higher level.

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