2012 5,1 hangs after Apple logo

[Hps1]

Hello there,

I just received a 2012 5,1 (12c 3.46ghz/64gb/500 & 1TB SSDs/GT 120 (soon to be replaced obviously))

The system would not boot the Sierra USB stick installer I made per Apple's instructions. So I installed Sierra to an SSD via a USB enclosure, which boots fine on my other Macs, but on the 5,1 it hangs after the Apple logo. No progress bar. Goes straight from Apple logo/blank progress bar to black screen. Computer is still on, keyboard lights still on, no video signal. Very strange. Attempting to start Recovery mode hits the same snag.

What am I missing here?

Thanks for any help!
HP

 

[ActionableMango]

I just received a 2012 5,1 (12c 3.46ghz/64gb/500 & 1TB SSDs/GT 120 (soon to be replaced obviously))

I don't know about your problem, but I will say that no 2012 5,1 ever came with a GT120. I suspect you got lied to about the age of the computer. It is probably a 2009 flashed with 5,1 firmware to accept Westmere CPUs. The 2009 came with a GT120.

Is it just Sierra that you are having a problem with? For example will this MP boot any other OS?

 

[Hps1]

I checked the serial and the result was indeed a mid 2012 model. That was the first thing I checked as I'd been worrying that might be the case. Guessing they just chucked the 120 in there so it had something.

I've downloaded Snow Leopard but as my other macs are running Sierra I'll have to do some digging around on how to create boot media (The installer won't open in Sierra)

 

[F1Mac]

There was no 3.46 option for the 12-core Mid 2012 MacPro, so the CPUs have been replaced, and the mid-2012, indeed never came with a GT120, it was an HD-5770. Out of curiosity, check your EMC number on the back of the computer what does it say?

 

[DearthnVader]

Did you try booting in verbose mode?

Hold Command+V at startup.

You might try to enable remote login on your Sierra USB drive, and use ssh to try dmesg, or have a look at the Console Logs.

You really have to get us some type of error message to go by.

 

[Hps1]

Here is the serial info:

A1289 EMC 2629 100
C07HT1A0F4MC

...So a 2012 with upgraded CPUs, correct me if I'm wrong.

This issue appears to be some sort of rookie error.

I plugged the SSD into another Mac, enabled screen sharing, put the SSD back in the 5,1, and what do you know? It is running fine. I wondered why the keyboard/system still seemed alive...

Switched the resolution to 1080p and the screen came to life. Seems the issue is either a) the GT120 doesn't want to spit 2560x1440 onto the monitor I have despite listing the res as a capability, or b) DVI to HDMI is incapable of it. I've ordered a MDP->DP cable to test (although it is sort of moot, just a stop gap until MVC finally get the 1080 TIs out).

Thank you both for the help nonetheless.
HP

 

[DearthnVader]

That's about what I figured, from what you described, it seemed like a video issue, rather than a system freeze of a kernel panic.

Glad you go it working.

 

[adam9c1]

Can you boot in verbose mode?

 

[Hps1]

Adam

All is well - it was simply a cable issue - thanks though