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muvaphuka

macrumors newbie
Original poster
Sep 16, 2010
4
0
Hi

Just looking for confirmation of my diagnosis for my iMac fault.
Basically, my iMac has started randomly shutting down completely, shortly after switching it on.
Just before it shuts down, the window pops up asking if I want to shut down, but it still shuts down no matter what option I choose.
I have noticed this doesn't happen if I turn the screen brightness right down, but if I start to crank up the brightness then it shuts down.
I'm fairly certain the power supply is failing, but wanted a second opinion before I bit the bullet and bought a new PSU.
The iMac is out of warranty and I have tried SMC and PRAM reset plus reinstall of OS (Mountain lion)
 
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