download CHUD Tools then massive power failure

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download CHUD Tools then massive power failure

HELP, PLEASE!!!
I've had my MACs for about 6 years now and never had any real problems. Recently however I noticed the G4 starting running quite hot and loud so I decided to use CHUD tools to cool it down a bit. I downloaded the app and ran the 'previous CHUD versions' checker as instructed. As soon as I clicked on it the machine shut down and I've been unable to restart since. (I don't think it actualy launched and I didn't get as far as installing the actual tools app)

The power light has a solid white light on when depressed, but goes no further. I've investigated the cause quite thoroughly and read all the forums about the G4 PSU failure,PRAM reset,battery changing,CPU reseting etc. I've done all of those and have the +5v trivkle on pin 1 of 24 of the PSU.
I've also tried a different hard drive in the machine - trying to ascertain whether it is the CHUD tools causing the problem (software/hardware problem?)and it still won't power up. Therefore I think that it's just a crazy coincidence that I launched CHUD and then had this failure as the 'non-CHUD infected' drive should have enabled the machine to launch I think.
So I'm wondering, I think it has to be either the PSU or power switch itself. I have the 5v trickle as mentioned, but are there further tests I can do on a 24 pin supply to confirm its status please?
If not, Is there a way of testing the power switch on the front of the machine please?
THANKS VERY MUCH IN ADVANCE FOR ANY HELP!
regards
Dan

g4 MDD dual 1.25, Mac OS X (10.5.7)

Posted on Jun 8, 2009 3:57 AM

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Answer 1

Denis Eddy

Level 4

3,571 points

Jun 25, 2009 10:17 PM in response to DannyBoyCook

Even if by 'PRAM reset' you mean use of the PMU switch, you may not have hit upon the single most useful first approach to an MDD that fails to start up: resetting the MLB.

Switch off mains power at the wall or power-board. Open the door and ground yourself on the internal metalwork, Remove the PRAM battery. Unplug the mains cable at the Mac end. (This is Apple's recommendation, but I don't follow it because Australian GPOs—power outlets—are universally grounded three-pin sockets. If your GPO tests as reliably grounded, as well as switched, you don't need to do so, either.)

Wait at least 10min. Replug the mains cable into the Mac (if you separated it above), but do not yet switch on mains power. Ground yourself again. Restore the PRAM battery only if it shows above 3.3V in circuit. Otherwise, replace it with a new battery. Wait 20sec. Press the PMU reset switch for 1sec once, and once only. If the switch bounces it will be interpreted by the PMU as two presses, with an entirely wrong outcome. The PMU is extremely sensitive to stray charge, so make sure that the hand that presses the button is also in contact with the metalwork of the door.

Close the door, switch on the mains supply and start up the Mac from the touch-sensitive 'button' on the ADC display. Given nothing worse than the Mac's former confusion as the cause of its failure, you should be up and away. If not, failure of your PSU is a distinct possibility.

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