imac 27" i7 mid 2011 rattling / buzzing noise left side
Hi, out of the blue my imac has decided to create a loud rattling / buzzing sound from (facing) left hand side. This sound is increased when the brightness is turned up.
I have checked all my fan speeds and temps which seem correct as this noise starts instantly on start up so its has nothing to do with heat.
Temp: 35C
ODD: 1148rpm
HDD: 1099rpm
CPU: 938rpm
When I turn up all the fans I can hear their noise are increasing but the the problem noise is still apparent in background!
I've done a CMS reset and resetting NVRAM / PRAM, that didn't solve the problem.
People have reported a high pitch sound but mine seems much louder and rattly as it can compete with a fan at full speed!
Also there are no changes in aditional items pluged into my mains supply as I noticed this can also create the noise.
The imac is out of warranty now so I'm hoping there is potential I could fix it my self, have opened macbook pro's and other mac items and not scared to have a look inside if need be.
Hope someone has come accross this as the noise is really really annoying and stoping me from working grrrrrr.
Thanks 🙂
iMac (27-inch Mid 2011), OS X Mountain Lion (10.8.2)