Problem with mid-2011 iMac

Hello all!



I have a mid-2011, 21.5" iMac. If I turn it on it starts up to the screen with network, recovery and hard drive options. None of them work.



If I click either of the drives it continues for a few moments, and then there is some 'static' in a band across the about an inch of the screen (logic board problem?), and then restarts, and then nothing, just grey. I can't start in safe mode. Resetting NVRAM does nothing. I have no peripherals connected and I removed the additional RAM.



I initially thought it was a hard drive failure, but I can access the data in Target Disk Mode. I have plenty of backups etc...
In diagnostic mode I get a different failure each test, such as: 4sns/1/40000000: TAOP-52.308


How can I diagnose the problem?



Thanks!

 

Thanks. I just gave up and arrived back at home with a new iMac. The more I thought about it the more it seemed like a hardware problem that wasn't going to be easily solved, and it was more or less time for a new one anyway.
So: 3.3GHz i5, 27", 2tb fusion, M395