PMU Reset


Would anyone know the correct way to do a PMU reset on an Imac G3 Graphite, 650mhz?
I sold this computer on Ebay, and the buyer was unable to power it up. He sent it back. I brought it to the Apple store. The tech took the computer in the back and reset the PMU. It was then able to boot up without any problems. I sent it back to the buyer and he is still unable to boot it up. I told him to hold the PMU reset button for a few seconds and then release it. He tried it multiple times and is still not able to power up.
Are we missing a step here?

We are aware of where the PMU reset button is (in the memory compartment).

Any help would be apreciated.


Yep, I just did one one my powerbook but it was via the keyboard. No magic buttons anywhere, I you sure you are doing it right?


There are 2 ways of doing it. One way is with the keyboard (like you did Lurk). One is with a button (I think called a CUDA button). It is there and is not called a magic button.
The problem is that the computer won't boot up at all. So holding these buttons down won't help.
The main problem is that I don't have the computer here with me (the Ebay buyer has it, and has been very patient with me). I'm pretty sure if I had it, I would be able to boot it. It's just that I need to pass some info to him.
When you press the PMU reset. Do you try to restart at the same time? Or do you wait a few second?


The Late: SuperMacMod
Yes, the CUDA button on the Logic Board. After pressing the button, you don't have to wait to restart.

Resetting the logic board can resolve many system problems. Whenever you have a
unit that fails to power up, you should follow this procedure

1 Unplug the computer.
2 Disconnect the cable that runs from the power supply to the
power filter board on the bottom side of the logic board/mass
storage chassis.
3 Press the Power On button on the front of the unit.
4 Remove the logic board/mass storage chassis from the unit.
5 Remove the battery from the logic board.
6 Wait at least 10 minutes before replacing the battery.


Thanks for replying.
Is this a long process? Please forgive me. I don't have the computer on hand to perform this. I know when I took it to the Apple store the tech took the computer in the back for only a few minutes. Can the logic board/mass storage chassis easily be removed? And is this accessable from the memory compartment? Or will the computer have to taken apart?
So after step 6 I would then try and restart the computer?


bobw, this is a Graphite iMac, which would make this much simpler than for an older iMac.
Just - -
1. Disconnect the power cord, pull the battery. If you have a voltmeter, it should be more than 3.3 volts DC. A low battery can prevent boot. I like to leave the battery out for a few minutes. Put the battery back in.
2. Press and release the PMU reset switch (S1) once on the logic board. Do NOT press the PMU reset switch a second time because it could crash the PMU chip.
3. WAIT ten seconds before connecting the power cord and powering the computer on.
If there are no other problems preventing boot - should work...


Mac of the SubGenius! :-)
Just a hunch: find out if this person is familiar with Macs. I've seen people tell me they couldn't turn on the Mac only to find out that it was because they didn't KNOW how to turn it on. So many people are used to the PCs with the power buttons on the front and all that they don't realize that some Macs require to be turned on from the keyboard if the keyboard has the power button. THis isn't always the case, but with those secific keyboards it usually is. You might have to explain to the buyer how to actually turn it on.

Yes, it sounds silly, but you'd be amazed!