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Performa 575 Board, no sound, cap + short to ground?

protivakid

New member
Have a 575 board here and the audio stopped working, system power-on sound, internal speakers, and both headphone jacks, nothing at all.

Looking at the board I can see the SMD component at L2 has leaked. It reads 101 which I believe this is a 100μH inductor but PLEASE correct me if I am wrong. I was planning to re-cap before I saw the inductor but I also noticed the + side of the top cap closest to the expansion is shorting to ground... guessing this isn't correct and not sure if it means there's another problem as well.

Q1 - Can anyone with a good 575 board confirm the positive side of that cap does NOT short to ground?

Q2 - Can anyone confirm the L2 inductor value and correct package so I can order a replacement?
 

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protivakid

New member
I thought this board had some life in it but perhaps not. Anyhow to those finding this thread down the road, a fellow user was able to confirm that the + cap pad I marked does indeed short to ground on his board as well. He also sold me two 101 inductors and with them I was able to restore audio to this mac.
 

Phipli

Well-known member
Note that the sound circuit has positive and negative voltages, so where you see the + connected to ground may be the cap between -5v (??) and gnd. In that case gnd is the higher voltage.

I've got dead sound on a 630 board, not had a chance to work on it lately.


There is a short somewhere and I've removed the DFAC II, some caps and the negative rail regulator and not found it yet. More effort needed!
 
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