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Maila87

macrumors member
Original poster
Jan 2, 2010
31
0
Hi,
I have second iMac 27" i5 with buzzing sound. Now the sound coms from the centre of the back top of iMac. The first one produced sound from the left corner, when the backlight is off, or the backlight is below the full intensity.

I tried everything, resseting PRAM, another power cable, disconnecting USB cables. Reinstalling system, changing RAM for 4 GB from my MacBook Pro. I also tried APC backup solution and power iMac just from battery and moved iMac to my neighbour.

Only one fix works temporarily and it is changing the speed of fans by SMC FAN.

What it could be?
 
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