[ottyee]

I just bought a 20" imac 2.4 and there is a hum coming from the computer when the brightness is adjusted up and down. The noise goes away when the brightness is turned all the way up. As i turn the brightness down the noise return and sometimes goes away. I've read on the apple support forum that it could be a bad inverter, is this true? Any help would be appreciated. Thanks in advance

[macryan]

Be sure that you have nothing in close proximity that might cause interference.

You might also try a different outlet.

HTH

[Veltliner]

Originally Posted by ottyee 

I just bought a 20" imac 2.4 and there is a hum coming from the computer when the brightness is adjusted up and down. The noise goes away when the brightness is turned all the way up. As i turn the brightness down the noise return and sometimes goes away. I've read on the apple support forum that it could be a bad inverter, is this true? Any help would be appreciated. Thanks in advance

I have the same issue on my 24" iMac and as soon as I can I will lug myself and my iMac to the Apple store to get it fixed.

Can you provide a copy of the post about the inverter being bad? So I can give the url of that post to the apple repair tech.

That sounds like a good tip. Because I had an non-apple, but apple certified tech going over my iMac, and he didn't find anything.

Add-on: inverter. What exactly does it invert? Where does it sit?

PS: it also gets noisy, when the screen dims before going to sleep, doesn't it? Like in your case, it disappears, when you set screen brightness to full (unfortunately this is totally unsuitable for photo editing).

[ibook_steve]

An LCD inverter is a circuit that generates the high voltage required to ignite and power fluorescent backlit LCD displays. Inverters can hum if a component on the inverter board has problems (the capacitors).

Steve

[Veltliner]

Originally Posted by ibook_steve 

An LCD inverter is a circuit that generates the high voltage required to ignite and power fluorescent backlit LCD displays. Inverters can hum if a component on the inverter board has problems (the capacitors).

Steve

Thanks. Now I'm well equipped for my apple store appointment.