iMac 27 " booting problem

[vish2575]

I have iMac 27" late 2012 model, recently I am facing problem of freezing and booting of my iMac, tried all possible diagnoses, formatted hard drive, logic board diagnose also showing no problem found. Now taken to the Apple authorised service center, they have also done all diagnoses and now they are saying that the logic board has to be change which is costing 42k in India, my Mac not in warranty so anybody can please suggest what can be done, thanks

 

[pm-r]

If you can find, borrow or use a good known compatible drive with 10.8.2 or later to boot from and test otherwise, their diagnosis is probably correct.

But it wouldn't hurt to do some searching on something like:
iMac 27" late 2012 possible logic board problem

https://www.google.ca/search?client...&oe=UTF-8&gfe_rd=cr&ei=KqAgVeOfMe7siALOnoGwDg