Randomly my mid 2011 27" iMac screen goes gray, flickers and then locks up with green vertical strips. Only way to get back to normal is reboot into recovery and then reboot again. Any ideas? I have done a complete clean OS install which lasts a few days then same thing happens.
Mac Pro, macOS High Sierra (10.13.1), 32GB Ram
Yeah, well that's the problem with AHT. If it reports a problem you can be pretty sure there is one. But reporting no problem there could still be one. Apple has much more sensitive tests they can run. I'd suggest taking it to Apple Authorized Service Provider.
Try an NVRAM reset:
Run Apple Hardware Test:
How to use Apple Hardware Test on your Mac - Apple Support
You may need the original discs that shipped with your Mac.
I have tried that several times also.
Did that, reported back with no issues.
Just not sure if its worth spending the $ on this old timer. Does Apple repair still have that flat rate deal? Will they test it for free?
Apple itself won't take it, they don't do repair on Macs that old. That's why I suggest an AASP. The diagnosis should be free, but you should get in touch and ask them their policy.
Is there a link to AASP's in my area?
Thank you
2011 27" iMac screen goes gray with green stripes
