This Power Mac G4 has Mirrored Drive Doors.

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Sound not Working Neither on startup or in OS

I recently acquired a Power Mac G4 MDD in which the sound does not work.

I'm fairly new with Macs, so I don't know what to try

The speaker on the computer looks blown, but any external speakers I try don't work on any of the ports.

I've tried putting in an SB Audigy and Audigy 2, neither of them got picked up in Mac OS

The only resemblance of sound is a little speaker pop on startup

I'm stumped, can anyone help?

Answered! View the answer I have this problem too

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Let's first see if it is the preferences. Go to System Preferences > Sound and see how it is set for out put. Plug the external speakers in (make sure they are not ones than need a special driver). Put the sound on line out. Make sure you selected the speaker port and not the microphone port. Let me know your results.

If I need to I can play with one of my two MDD machines. Are you running 10.5.8?

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I tried this, and it was switching between line out and internal speaker.

No, I'm running 10.4.11, but I'll try 10.5 in a few days


Also, if it helps, it lags when I press volume up and down on the keyboard.


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I think I found the problem

Yesterday, I was using this computer with the ADC monitor I got with it, and all of a sudden, the bottom backlight went out.

I was confused, so I rebooted the thing, the monitor was fine at first, then it went out again.

I decided to test another video card, same problem.

I hooked up that monitor to my 2002 G4 QuickSilver, and then it worked just fine, so I believe the power supply is failing, and thus might be the reason for the audio not working.

Could I possibly use the PSU from my QuickSilver to test if it was the PSU, or would it consume too much power?

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If the power supply pins and voltages are the same for both computers then it will likely work ok for the test. The wattage rating should be in the same ballpark, either higher for the good supply or > 75% of the rating of the bad one. I don't know if Macs use a standard ATX pin connection but see if the wire colors match between supplies before using. Power supplies don't usually fail by getting weaker but maybe something in the Power Mac G4 is drawing too much current or a voltage is out of spec. Check the voltages with a DVM if you have one and they should be within +/-5% of rating. Here is one site that might help. (no www.)


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Robinton Santos will be eternally grateful.
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