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iBook G4 won't boot after PMU reset

Message #1 - Posted 2005/12/28 - Richard Burke

iBook G4, 933 MHz, OSX 10.4.3

The battery life was getting really low so I reset the PMU, in hopes it might help...

First time after the reset, the iBook started, then asked me to reset time and date. I tried to - and it froze. I force-rebooted (no choice), and all I got was a screen that gradually went from dark to blotchy bright white, and then to purple. The hard drive never started up, nothing. I reset the PMU again. Same thing. I only get the blotchy screen. I've now tried several times.

I started the iBook in target mode and checked - everything still seems to be where it should be on the drive. But, wierdly, the 'target' sign on the iBook's screen got all broken up.

Any ideas what I can do? I'm getting a little desperate, cos I need to use the machine daily.

TIA

Richard

Message #2 - Posted 2005/12/28 - morenuf

Previously, Richard Burke wrote:

iBook G4, 933 MHz, OSX 10.4.3

The battery life was getting really low so I reset the PMU, in hopes it might help...

First time after the reset, the iBook started, then asked me to reset time and date. I tried to - and it froze. I force-rebooted (no choice), and all I got was a screen that gradually went from dark to blotchy bright white, and then to purple. The hard drive never started up, nothing. I reset the PMU again. Same thing. I only get the blotchy screen. I've now tried several times.

I started the iBook in target mode and checked - everything still seems to be where it should be on the drive. But, wierdly, the 'target' sign on the iBook's screen got all broken up.

Any ideas what I can do? I'm getting a little desperate, cos I need to use the machine daily.

TIA

Richard

Not certain, but if the PMU is corrupt it can drain even a new battery with a day instead of 3-5 years. Pressing the PMU(on a desktop) too many times can lead to a corrupt or otherwise unhappy PMU.

Could it be that your battery is dead or perhaps run dead your accidental too many presses of PMU?

Can you check your battery or replace it? Should be a 3.6volt lithium battery on desktops (not sure what is in a laptop).

The PMU controls many startup functions as well as the PRAM. If it is screwed up or the battery dead many Macs cannot start correctly or at all. On desktops no video is a common symptom of dead PRAM battery or PMU corruption.

A PMU reset will reset the PRAM so asking for you to set the date & time is normal.

Good Luck

Morenuf

morenuf@nobodyhome.com.invalid

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