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Chester Jan 28, 2013 06:19 AM
Imac G5 will not boot after power outage
Imac G5 20 inch isight ...
this happened before and I found help from some one who posted a method of removing all connections to the Mac ... including the power chord ... then ... something like hold in the start button for some time ... replacing the connections and pressing the start button ... It worked but I forgot the sequence.
Any one with the answer?

chris v Jan 28, 2013 09:41 AM
That's probably the pram reset instructions for an Intel iMac --

From Here:

Reset your computer's PRAM (parameter RAM) by doing the following:
If you iMac is on, turn it off by pressing the power button until the computer turns off. You should hear the fans stop working.
Press the power button to restart your computer and immediately hold down the Command, Option, P, and R keys simultaneously. Make sure to keep holding down all four keys while the computer starts up.
When you hear the startup sound for the second time, let go of the keys. If you don't hear a second startup sound, repeat these three steps again; the second startup sound indicates that you have successfully reset the computer's PRAM.

If it continues to give you problems, you should open it up and have a look at the capacitors -- they went bad on lots of these. Google for "iMac bad capacitor" and you'll find plenty of info on how to identify them.
P Jan 28, 2013 05:22 PM
No, I think he's describing the SMU reset procedure. That seems like the right thing to do if the iMac won't boot. If so, this is how.
Chester Jan 28, 2013 07:52 PM
With multiple attempts, after peripherals were unplugged,... I plugged in while depressing the start button, ... released it ... pressed it again and ... that wonderful C chord! Backup completed and now to the store for a new battery fur the UPS that I will use this time.

Thank you P for the link :

"try resetting the SMU. To reset the SMU on one of these iMacs:
Turn off the computer by choosing Shut Down from the Apple menu, or by holding the power button until the computer turns off.
Unplug all cables from the computer, including the power cord.
Wait 10 seconds.
Plug in the power cord while simultaneously pressing and holding the power button on the back of the computer.
Let go of the power button.
Press the power button once more to start up your iMac."
chris v Jan 29, 2013 04:12 PM
I stand corrected! Glad it worked.
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