View Full Version : G4 750mhz won't turn on /accidental unplug

04-09-2009, 03:37 PM
my G4 mac has never had an issue.....

i was moving my desk and i accidently unplugged the surge protector from the wall and my mac shut down while running....i plugged it back in and nothing... no light-no chime- no anything....i looked at the following thread: ( http://www.macgurus.com/forums/showthread.php?t=13867) i tried everything (except unplug overnight) but still no luck......i currently have the battery, ram, video card, pcu and power cord removed.... hoping it my discharge or somethingby morning .....

what exactly happened? it appears that the power supply died but i just don't see how an accidental "unplug" could do this to a mac !

i'm screwed... i just lost my job after 18 years of hard work and can't afford to go to the Apple Store ! help please...

04-09-2009, 05:29 PM
Any electronic device can be destroyed by Sudden Power Outage Syndrome.

The obvious questions that comes to mind is:

Is the motherboard battery dead? (and hence the PROMs possibly corrupted)

You say you tried all the steps. Does that mean that you pulled all PCI cards, memory, drives and power, hit the CUDA reset. Then plug in and power up with nothing installed but a CPU? That is a great way to see if you can force something to happen. If it won't at least give a breaking glass sound of no memory then the problem is base hardware issue such as power supply, motherboard or CPU.


04-09-2009, 05:36 PM
Bummer, I guess I never expected a mac to die from being unplugged while on...it's happen a couple time before with no recourse.......

Yes to everything but the drives...... i'll pull everything else tonight...... then i'll let it set over night ( if that's what you suggest)....

the CUDA reset is the little square button by the battery ( right?) yes, i tried that..... and it has a newer battery ( 4 months ago) ...... I did however have to reset my clock and date which tends to point to a bad battery???? what if the PROMs are corrupt???

i know i'm asking alot here and i appreciate your hekp!

if this baby dies from S.P.O.S., i guess the dreaded mac store is the last result, eh ????

04-09-2009, 08:52 PM
Also, does anyone care to guess what the statistical chances are that this is a smoked power supply? ( caused by the accidental unplug) ????

04-10-2009, 12:04 AM
What else can you tell us? When you push the power button, do you get anything? Lights.....the drives spin up, the fan in the power supply spin up?

Could be the power supply, or it could be a internal fuse or circuit breaker. Having had a couple apart some years back, I seem to recall an internal in-line fuse. The problem is it is a bit of a project to get the PS out and apart to inspect.

Should it be the PS, or something else, if you very handy you may be able to fix it. One thing to consider is that if the PS (or more) is cooked, often a used Mac in complete, working condition than buying parts to fix an old one. So be sure to price out the options before you start a rebuild project.....should it come that.

We can help with the numbers.

04-10-2009, 11:01 AM
Thanks for the input. Absolutely nothing happens when the power button is depressed. No fans, no lights, drives don't spin.... basically dead...

I tried all the voodoo stuff. I unplugged literally everything ( ram, drives, PCI cards, etc...) and let it sit overnight. Still nothing.

However, for any of electrical engineers out there. I did notice that when I initially plug the mac back in, the lights dim for a very brief nano second. Which is usually an indication of a current draw. But again, nothing.

I'm going to pull out the PS today to see if there is any fuses or breaker..... I can't fathom that just an accidental unplug fried anything but as Rick said, anything is possible.

Also, the option of buying another stripped down mac in working condition is definately an option. I have this thing built to the max for music applications and could just start swapping things out. However, a recent job loss has me at a financial disadvantage...UGH

04-11-2009, 03:04 PM
I thought you would like some additional info..... i pulled out the power supply and there was no inline fuse. i also took the power supply apart & nothing..... so, i cut my losses and found my cheapest solution......I bought an indentcal mac online for $109 !!!!!

thanks to those who helped..... if there is any more ideas, I'd like to hear them......

04-11-2009, 06:44 PM
I think you made the right choice. Kind of a pain to have a G4 scrap yard, but cheaper to buy whole, booting machines than the parts from scalpers. Post of here if you need more parts....some of us are getting rid of our G4 parts.