5 Replies Latest reply: Jun 7, 2013 7:32 AM by jwukitsch
jwukitsch Level 2 Level 2

When I try to boot up iMac G5 PowerMac, it turns on the sleep light, no screen and then all of the fans get into turbo mode. Please help!!

Reply by BDAqua on Jan 10, 2013 10:24 AM Helpful

Is the light blinking in a pattern?


Fans will come on full speed if no OS is loaded to control them.


Can you count the beeps or flashes?


1 beep = no RAM installed

2 beeps = incompatible RAM types

3 beeps = no good banks

4 beeps = no good boot images in the boot ROM (and/or bad sys config block)

5 beeps = processor is not usable


In addition to the beeps, on some computers the power LED will flash a corresponding number of times plus one. The LED will repeat the sequence after approximately a 5-second pause. The tones are only played once.


Note: In this case, a flash is considered to be 1/4 second or 250 ms or greater in length.




Does anything show on screen if you hold alt key at bootup?

Reply by BDAqua on Jan 10, 2013 6:15 PM Helpful

No screen light at all?


iMac G5 SMU reset...



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