powermac g4 not powering on

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Level 1

8 points

powermac g4 not powering on

I have a powermac g4 mdd that until afew days ago has been working just fine however it then started having a boot issue in which it will not respond (no power button light or fans) when the button is pressed. the only way to get it to work is to unplug and replug the powersuply then push the button and it starts fine. I'm positive that the pram battery is dead and there is a red light on the logic board. Any help would be appreciated.

PowerMac, Mac OS X (10.4.11), G4 mdd 2g ram

Posted on Apr 11, 2015 12:24 AM

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Answer 1

Allan Jones

Level 9

68,774 points

Apr 11, 2015 7:22 AM in response to bmrm145

MDD G4s have an above-average rate of power supply failures. This article will help you diagnose the PS to see if it has failed:

http://www.jcsenterprises.com/Japamacs_Page/Blog/D275729F-09DA-4FBB-96B3-BEEEB2C 04619.html

Assuming the PS is OK, move on to the next suspect. The front panel board that contains the power button is also a trouble spot. With some versions you have to push the button "just right." Try pressing the upper right quadrant of the button, then the upper left. Front panel boards are still available on the used/pulled market and are not hard to replace:

http://www.dvwarehouse.com/Apple-Front-Panel-Power-Button-Board-for-PowerMac-G4- MDD-922-5276-820-1339-A-p-31929.html

If you think the FPB is at fault but cannot find a replacement, there is a possible workabout using an old iMac USB keyboard. The early iMacs shipped with the model M2452 keyboard, the only Apple USB boards that have a power button on the keyboard. A long-time Apple tech said the M2452's power button would override a dead button on the front panel board.

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