[col010]

Lately (the past 2 months) my G5 (dual) has been suddenly shutting-down. The system log reports a "PMU forced shutdown, cause = -122".

Seems to be a lot of posts relating to this problem (HELLLOO APPLE...) But the striking thing is that no one has claimed vistory over this EVIL ILLNESS!

There are an assortment of "remedies" suggested out there but noting conclusive. Could it be that those that resolved the problem just dissappear into bliss and forget to post a follow-up? I forgive them -- but not Apple: their site just lists instructions on resetting the PMU (Resetting the PRAM and the PMU have done nothing ).

Could it be a marginal Power Supply?
A dying battery?

Logic board problems?

Firewire wierdness?

Some theorize that it could be an sudden drop-outs in my home electrical supply. Ok, that could theortically cause a sudden freak-out of the PMU.. but if that's the case, why is it happening now all-of-a-sudden after a year of no-complaint servce? I live in a modern home in a modern city and i never have blackout, brownouts, dips/surges in pwer -- nothing, not even a lightning storm. I've even shut down all home appliances to see if that is triggering a surge.
Many people think there is some link btwn whatever software upgrade they've recently done and this issue -- I have seen fingers pointed at the latest upgrade of Quicktime, Tiger, Panther, spotlight and even iTunes.

I give up (almost).
Does anyone have any deeper insight into this issue, suggested solutions etc ???

[Macola]

Since I started the original thread last year, I'll post my results. Note that mine was a GigE model originally (upgraded to a dual 1.4 G4) so your situation may be different.

I replaced the power supply and the problem went away. I have used the Mac since then for about a year now, running 24/7, and just recently it started having problems again--this time it wouldn't start up reliably. Since I had moved to another Mac as my primary machine, I decided not to spend any more money fixing it. Instead, I moved the guts into an old Sawtooth that I had lying around and left it at that.

[col010]

thanks for the update!

[Big Mac]

It makes sense that a power supply defect would be triggering random PMU shut downs. In a previous era of computing power supply problems could cause random restarts, but I bet the more sophisticated power management circuitry and software in modern machines causes shutdowns due to power supply issues instead.

[Abit667]

I'm getting this on my dual g4 867.

Just got the first one like 2 minutes ago, really weird since I just read this thread and then it happened, first thing I checked was dmesg and there it was.