Mac OS 9 Lives

Mac OS 9 Discussion => Hardware => Topic started by: blazer1878 on May 11, 2026, 09:15:40 AM

Title: Powermac G4 Sawtooth shuts down after a second
Post by: blazer1878 on May 11, 2026, 09:15:40 AM

For some reason this powermac turns off after a second. Firstly it started to freeze and kernel panic, then it gave up. I replaced psu 2 times using guide from atxg4.com, but it still does this. Nothing is connected apart from cpu and power, psu should be functional.

Title: Re: Powermac G4 Sawtooth shuts down after a second
Post by: blazer1878 on June 07, 2026, 03:23:19 PM

Pls help as i don't want to gut this powermac to put board with laptop core duo cpu in it  >:(

Title: Re: Powermac G4 Sawtooth shuts down after a second
Post by: ovalking on June 08, 2026, 05:16:06 AM

Is the power button working ok? e.g. sometimes they stick and don't retract properly.

Title: Re: Powermac G4 Sawtooth shuts down after a second
Post by: blazer1878 on June 08, 2026, 02:07:21 PM

It does, i don't think that it's issue with powerbutton, as it is constant

Title: Re: Powermac G4 Sawtooth shuts down after a second
Post by: smilesdavis on June 11, 2026, 01:23:58 AM

Sounds like hardware degradation

* CPU daughtercard
* CPU VRM / voltage regulation -> vheck caps corrosion burnt mosfets
* Logic board fault byebye
* Reseat CPU card
* PMU reset (once)
* do a Minimal config test