VERY noisy 20" iMac after PMU reset...

[Huw]

I've just been on the phone with apple, following the probems I've had with my iMac randomly switching itself on at night... anywaym they told me to reset the PMU (the unplug, and pressing the power button while unplugged etc), and that maybe the reset would fix the problem.

Anyway, after doing the reset, the fan on my iMac seems to be stuck on full speed, and is making so much noise its rediculous!!

Is this normal after a PMU reset? Will the fan shut up after a while? or should I just give apple a call back?

Cheers

 

[Viira]

same thing had happened to me when I did that, but I just read here:

https://forums.macrumors.com/posts/2960049/
and
https://forums.macrumors.com/posts/2960056/

that holding down the power button and plugging in the power cord is not the way to reset to PMU on the 17" 20" and 24" iMacs, its only for the G5

anyone wish to clarify?
and so then what exactly would the holding down the power button reset?

 

[iMeowbot]

Here is the reset procedure for the iMacintels. SMC is what those wacky kids are calling the PMU now.

 

[Huw]

Here is the reset procedure for the iMacintels. SMC is what those wacky kids are calling the PMU now.

What happens say, if the person that I phoned at apple told me to hold the power button down while plugging it in, and since doing so, the fan wont switch off?

Will holding down the power button fry the PMU/SMC or something? is there anyway to fix this?

 

[iMeowbot]

What happens say, if the person that I phoned at apple told me to hold the power button down while plugging it in, and since doing so, the fan wont switch off?

Will holding down the power button fry the PMU/SMC or something? is there anyway to fix this?

I don't think anything has been fried, the full speed fans seem like a default that would be safest for keeping the insides cool.

By the way, that procedure above is for the Intel iMacs, is that what you have? If you have a G5 model, here is the SMU reset procedure (SMU is yet another wacky name for a PMU).

Why not try the documented reset for your model and see what happens? Maybe that will be the end of the problem and you won't have to worry more.

 

[Pete Dog]

thanks imeowbot

Wow thanks I have an intel based imac which i thought for a while was a G5 so I was following the instructions for the G5 smu-or-whatever-it-is reset. the fans went wild! but by following the link above and doing the correct reset for intels, it's quiet as a mouse-ish. the moral: don't mistake your intel for a G5.