2012 iMac 27" Can't Start Hardware Test

[pbedrosi]

I just installed new blade and SSD drive, having fan issues (made a post about it). I just want to run the hardware test on the machine.

I shut down the iMac, turn on the iMac while pressing key "D", and spinning globe comes up on the white page, then this error pops up.

 

[SPDucharme]

I have the same problem with the same model iMac. I added two more 8 GB memory cards a few weeks ago. Soon after, the computer began crashing after about ½ hour. Is there an alternative to Apple Hardware Diagnostics?

 

[DeltaMac]

The network/internet diagnostics don't work on some older Macs. I have read that some firmware update inadvertently removed that online testing capability.
You CAN download the hardware test app for your Mac (2012 iMac, 27-inch would be the iMac13,2. It's in the list for download here - https://github.com/upekkha/AppleHardwareTest

 

[SPDucharme]

Thank you very much, DeltaMac.

 

[DeltaMac]

You can also try using your iMac after removing the new memory that you added --- does that fix your crashing issue?
Many Macs can be pretty finicky about RAM. It's often best to stick with brands that are known for good compatibility on the Mac, such as Crucial.

 

[SPDucharme]

Good suggestion - I will try it. I bought the memory from OWC, which I have good experience with. The specs match the Apple memory. I was finding the memory pressure high with only 16 GB, so I expected the extra 16 GB of memory would speed up the iMac. It didn't seem to help.

 

[DeltaMac]

OWC, in my experience, has pretty good tech support.
My suggestion still is good, I think: Use your iMac for a few hours with just the old memory installed.
Then, reinstall the additional memory. Double-check that all sticks are fully seated, then use all your memory. If you continue to get the crashes, contact OWC to get replacement memory. I think if you explain that you have tried with new memory out, then installed again, and you continue to crash with their memory installed, that OWC should easily ship out replacements. Hope that helps you.

 

[SPDucharme]

Follow-up to problems with my late 2012 27 inch imac restarting and spinning cursor. The old and new memory worked fine separately and together.

EtreCheckPro sait that the HD was about to fail, so I made a boot disk on an SD card and the computer ran fine after that. I have ordered a 2 TB SSC from OWC and plan to use that as an external boot drive so I do not have to open up the computer. I may also try to split the internal hybrid drive so that I can put the system on the 120 GB SSD and put everything else on the ecternal SSD.

Thank you DeltaMac for your help.