8 Replies Latest reply: Feb 5, 2013 7:52 AM by 165650
wonky-rat Level 1 Level 1 (0 points)

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.



iMac (27-inch Mid 2011), OS X Mountain Lion (10.8.2)
  • BDAqua Level 10 Level 10 (121,205 points)

    Hello, must be to do with the backlight/inverter, only thing I know of that has halves & connected to Brightness.

  • wonky-rat Level 1 Level 1 (0 points)

    Ah ok thanks for the reply, does seem to be something of the sort just annoying that other people are reporting it works fine when brightness is up!!


    I'm hoping apple will do something but being its out of warranty I'm doubtful they will without extreme costs for labour.


    does anyone know if a replacement board would fix the issue?

    Plus people are saying that EU/UK machines where getting the issue due to higher voltage so leaves me wondering if both inverter and psu need fixing!!

  • andy_gib Level 1 Level 1 (5 points)



    I had something smiler on my 2010 imac. I thought it was the fans and left it for a while until it started getting worse. No other problems other than a clicking sound, more noticeable when screen was turned up. I decided to take it to apple and it turned out it was the PSU unit. Apple replaced it as it was still in warrenty. I think it was around £200 on the invoice

  • wonky-rat Level 1 Level 1 (0 points)

    hi, this is what worries me I'm unsure if its the psu or the inverter board!! I'm a bit annoyed as after a long call to apple they basically said out of warranty by 6months you deal with it!! I can't even go for EU consumers rights as I have to prove the fault was there to begin with!! haha but that would of come to no good as I use my iMac for work so there is no chance of using the consumers act there!!


    Spending this much on a machine you'd expect it to last more than a year and a half!! so glad I've backed apple for the past 10 years and bought plenty of products then get fobbed off like this!!

  • wonky-rat Level 1 Level 1 (0 points)

    have to add I know they offer apple care but the additional £200 is substantial when you're a freelancer!!

  • 165650 Level 1 Level 1 (0 points)

    Hi Wonky-Rat,


    I had a similar problem, only mine developed into the Left Hand side of the screen going dark.  It started last week with a buzzing noise combined with the L/H side flickering from normal brightness to dull and finally permanently dark on the L/H side.


    If you check this discussion forum, 27" iMac/i5 Intel core, built mid  2011 are having the same problem.  I purchased mine Sept 2011.


    I have just spoken to Citizen Advise (0300 3300 650). 


    They quote the following; "If the product is more than 6 months old, then the burden of proof lies with the consumer to prove there is a manufacturing problem".  check out www.adguide.org.uk Under consumer.


    I spoke to Apple Technical yesterday and advised me to take the iMac to the genious bar for a "Service".  But thy confirm Apple have no Recall Notice for my machine, although I have seen a statement from a member of the forum based in San Diaego,Apple have accepted liability.  When presenting this to the Techy, he said it didn't apply to my machine.  Personally, I don't think he can comment on it until Apple allow it.


    I'm going to my local Apple genius bar on Thursday to see what they say.  I'll keep all posted.


    Wish me luck.  One consumer has already paid out £400 to have the problem fixed.

  • wonky-rat Level 1 Level 1 (0 points)

    Hi, thanks for taking the time to reply.


    Yeah they informed me that was the case I would need an engineer to prove the fault was there from start and how can you prove that!!


    The only way for anything to take affect is to get numbers involve so they can recognise it as an error. With over 10 years of purchases of apple products I've always paid the price tag as I expected a higher quality product and this is the first time I've been disappointed and why I contacted apple.


    Things get wear and tear we all have to admit to that but a crucial hardware error like this after (for me) year and a half is unacceptable. The time scale varies.


    Adding from what I've read on other post it seams the error progressively gets worse and worse and ends in non backlit screen!!


    so if others are having this problem then post on here and tell apple as the more who report it the more likely they are going to pay slight attention to what I would assume is a hardware error not user!



  • 165650 Level 1 Level 1 (0 points)



    Ditto your senitments. I've spent £4.5K plus in the last 5 years on Apple products.


    Should you go the repair route, Google "Authorised apple repairs".  I've got a company ready and waiting in the background to uplift and repair and deliver back to me should Apple resist their morale obligations.


    Good luck.