Fix 2002 iMac power problem with PMU reset

Feb 28, '02 12:45:08AM

Contributed by: Anonymous

Although not strictly OS X related, many readers will probably be using OS X on the new iMacs, so we felt this important to pass along...

I just received a new G4 flat panel iMac. After loading a beta driver for Kensington Mouseworks, I went to restart my iMac and and ended up with a hung-up system (spinning beach ball on blue screen).

I shut down via the power switch, but when I attempted to restart with the power switch, alas no power! I contacted Mac Technical Support, Mac's Tech department spoke with their engineering department and it seems that the new iMac uses a chip circuit for power management.

To remedy this problem you must open the bottom of your iMac. Next to the memory slot, there is a tiny rectangular button under a protective plastic covering. Press this just once, and power will be restored.

[Editor's warning: "A MacInTouch reader warned about gratuitous use of the flat panel iMac's hidden, special reset switch, something Apple Support sometimes has customers use when the computer fails to operate. This operation apparently resets the "PMU" (Power Management Unit) but can cause serious problems if not performed in precisely the correct way, with the power cord removed and with a waiting time after the push - and it should never be pushed twice in a row, because it could "crash" the PMU. (The operation also resets PRAM, so settings, such as time and date, must be re-entered.)" ]

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