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nycdunz · Jul 12, 2005, 11:24 PM

sigh, i went to shut down my g5 today, and now it wont even turn back on, when i press the power button the light shines for like a few seconds and goes right off wtf? all out of nowhere this started happening and my g5 is like 2 months old... i never had this problem before, its the weirdest problem, i even tried unplugging it and plugging it into another outlet, the same thing...

sigh, im having so many problems lately, 1st my airport base station craps out, and then my airport extreme, and now my g5 wont even turn on. I am on my powerbook now, thank god, can someone please tell me what may be wrong? all was fine before i went to shut down my computer... geez

Barney2 · Jul 12, 2005, 11:49 PM

Check to see that your PCB box behind the switch button has not become dislodged.

nycdunz · Jul 13, 2005, 12:10 AM

i left it sitting there for awhile, and turned it back on, and it worked... but now it turns off automatically after a few mins, what gives? sigh... i have a new dual 2.7ghz g5 and it has no PMU button, so i disconnected the power cord from the machine and let it sit for like 10 minutes to reset the SMU or whatever, turned it back on, it worked, and then it shut off on me again... sigh

anybody have any similar problem and know what it can be? what would cause it to turn off like this, and not turn back on at random times, geez...

I will check the power button that you mention, but i highly doubt it... i'm so frustrated right now!

Barney2 · Jul 13, 2005, 07:34 AM

I have seen some users say to reset the PRAM for similar problems (resets to factory default)

Good luck mate!

nycdunz · Jul 13, 2005, 10:29 AM

can anyone please help me? my g5 starts up after i remove the cord for a few mins, but then it shuts off by itself like a few mins later, and then i have to unplug the cord again for a few mins before i can start it back up again, sigh... i don't think my mac has a PMU, because its the newer g5's... what else can i do b4 i take this to apple? which i really dont want to, its a far drive, and this thing is heavy to carry all the way into the mall

, geez... someone please help me out

OogaBooga · Jul 13, 2005, 10:30 AM

Do you have your schedule set to shutdown at a certain time?

nycdunz · Jul 13, 2005, 10:38 AM

nope i don't, i highly doubt it, i cant even power the thing on after it shuts itself off... i have to unplug the cord n let it sit for a few mins before i can turn it back on again... very strange, this happened out of nowhere, never had this problem b4

its not like my computer is old, i just bought this thing like 2 months ago brand new... and its giving me problems already out of the blue. i am very upset and stressed out about this... sigh

Sijmen · Jul 13, 2005, 11:10 AM

Could it be that your system is overheating? I have no experience with PM's but judging these symptoms I would say that the system is preventing some kind of meltdown. So logically something is busted, maybe one of the CPU coolers or even a fan.

nycdunz · Jul 13, 2005, 12:52 PM

i don't think so, i had my machiine off for hours, and it still wouldnt turn on... and when it did, it was only running for about 2 minutes and then shut off again... how can a cpu overheat so quickly? sigh, i really dont know what to do... i will give it another try when i get home from werk,it's been unplugged since last night. i really hope that the problem fixes itself... i do not want to go thru all the hassle of unplugging everything, packing it up and driving far away to the mall and having to carry that thing all the way to the apple store inside the mall...

geez, who would think spending over $3000 on a machine that it would have problems like this already... i'm very disappointed. i have the worst of luck with these things.

GSixZero · Jul 13, 2005, 12:55 PM

Call Apple, it's a hardware failure.

Waragainstsleep · Jul 13, 2005, 01:43 PM

We had one do something similar the other day. Wouldn't boot at all though. Straight out of the box. I searched Apple support for a PMU reset procedure, but didn't find one.
If yours came with a hardware test CD, you could try booting from that. (Booting from any CD will tell you if its hardware or software. (If its software, it should run fine from the disk. If it shuts down again, its hardware.)

Have you checked that the pull out fan module is properly installed? Have you listened to the fans or checked that they are running? Useful thing that plastic inner window. Check RAM and PCI cards are seated properly (ie re-seat them). You could try running it in firewire target mode. A dodgy logic board will somtimes fail to do this. It might also allow you to run some repair utillites on the HD for good measure (Diskwarrior is best, need v3.03 for Tiger). Plus if it runs without shutting off, it again implies an error on the HD.

G5man · Jul 13, 2005, 04:11 PM

do you have a MacAulley mouse? I know one of my friends had one and once their iMac started up it would shut down because of too much power being sucked in by the mouse.

nycdunz · 04:53 PM

ok i just got home from work, plugged in my g5 again, it started up, but then the same thing happens it shuts down on me again... i was lucky enough to load up the console and check my system log, and i see that it says

PMU Forced Shutdown cause = -126

and another one that said

PMU Forced Shutdown cause = -122

not sure what those means, if anyone happens to know what those numbers mean, let me know please. I need to know whats causing my computer to automatically shut down like this. This never happened before. I havent touched anything, installed anything whatsoever. Only thing I did before all this weird shutting down started to happen was update to OS X 10.4.2. But im still skeptical whether to believe that the upgrade cause this to happen. I was able to use 10.4.2 just fine, but when i decided to shut down my computer and to go turn it on again, the led will go on once and go off everytime i press the power button on my g5. Now when i press the power button, no light goes on at all, its like its dead... only way for me to get it to start up is to unplug it from the back. Everytime i replug it back in and press the power button, i hear the fans starting up, etc and then the light goes on... it doesnt go on right away, not sure if this is normal but i never really paid attention to when the led actually goes on....

seanc · Jul 13, 2005, 04:59 PM

Doing a quick google it seems that error -122 is caused by overheating, so it does indeed seem like a fan or something else has failed.

Judging by the speed in which it's switching off, i'd guess the CPU(s) are overheating as they get hot very quickly. Check the fans.

Try moving your G5 to an open space, take off the side and poing a fan inside and see what happens.

If the problems stop or take longer to occur then you know what it is an overheating problem, and that something is not being cooled right.

Good luck,

Sean

nycdunz · Jul 13, 2005, 10:05 PM

i opened up the machine, all fans were running fine... i saw a reset pmu switch, so i tapped it just once, waited a few seconds, plugged it back in, and still the same, now it shuts down even faster, i dont even get a chance to see the apple boot screen, sigh... whats going on, i tried almost everything possible... i even tried to boot up with my hardware cd to run a test, but not even that is possible because my machine shutsdown so fast, i have no chance, geez...

Gelfling · Jul 14, 2005, 02:41 AM

Perhaps the heatsinks are no longer making good contact with the CPUs. Or if you have water cooling, perhaps something has gone wrong with that.

Have you traveled with the mac recently or moved it about, perhaps the movement dislodged the heatsinks somewhat.