My iMac Screen occasionally flickers and dims

[AllanGreen]

For the last month my iMac has begun to occasionally flicker for about 1 second and then dim slightly. After about 5 minutes it has returned to its normal brightness.
Its not causing too much of a problem, but its obviously not right.
I wonder if its on its way to the knackers yard or wether its a victim of my upgrade to Yosemite.
Has anyone a similar problem, or ideas?

 

[pm-r]

Lots of users have had similar problem if you want to check:
https://www.google.ca/search?client...&oe=UTF-8&gfe_rd=cr&ei=d-6dVMOkDsKFoQTO7oCoBg
or more specifically for your iMac model try:
https://www.google.ca/search?client...&oe=UTF-8&gfe_rd=cr&ei=Ku-dVJ-tAYXDoAS_uIHIDA

But you could start with a PRAM and SMC resets and also try booting into Safe Boot Mode and see if either fixes your problem.

 

[AllanGreen]

Thanks for the help,
Just one thing, Whats a SMC Reset

 

[harryb2448]

Google is a marvel:-


Intel-based Macs: Resetting the System Management Controller (SMC) - Apple Support

 

[pm-r]

Google is a marvel:-


Intel-based Macs: Resetting the System Management Controller (SMC) - Apple Support

+1. Thanks.
And as they say - Google is your friend.

May everyone's HAPPY NEW YEAR searches find whatever they need.

Let me google that for you

 

[AllanGreen]

To be honest the google sites don't help as I don't have a problem as they describe. My screen just flickers and dims once every half hour or so. Not on one side as the googlers describe. I also tried switching off and restarting (SMC) but nothing changed.
So
I wiped it all and reloaded Yosemite - Still no change
I wiped it again and installed Mountain Lion and "Yey" my problem as gone, well at least for now it seems. Now all I have to work out is how to retrieve my Yosemited files off my Time Machine!; But at least I know I don't have to bin my Mac.