68kMLA Classic Interface

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Performa 575 audio troubleshooting
Posted by: ereuter on 2026-08-14 08:32:50 I have a 575 that had been in storage since 2001. I have recapped the logic board and only found one leaky cap (C16) that had eaten the MINUS5V trace in the vicinity of the edge connector. I fixed the trace and -5V is showing up where it should. All of the other voltages also look good in the audio section (op-amps, and the DFAC-II chip). I'm getting very faint but undistorted audio from the speakers. Front headphones seem to work, but then it doesn't go back to the speakers. CD audio is garbled. I have a feeling the OUTSENSE logic may be part of this. And I'd also like to get to the amplifier for the speakers and front headphones. - What does OUTSENSE actually do? It's logic signal. Does it just change the output gain? - How can I access the speakers and headphone jack on the front? There's a metal shield over it and I can't figure out how to remove it. - Is the amplifier for the front on the analog board, or a separate board? I haven't found schematics for anything by the logic board. Other thoughts? Thanks- Eric
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