Imac pro A1862 switch off after apple logo and half progress bar

[sajidmirza]

Hi,
I got a iMac pro A1862 820-00967 in dead conditions, restored in apple configurator successfuly.installed macOS Catalina from internet recovery successfully but after installation it boots with apple logo way to the half of progress bar and shuts down.replugged 2 ssd's of 512GB and cleaned all the RAMs.Still not completely booting.tried PRAM reset but lo luck.Can any one guide me what should I do next.

[reformatt]

Catalina is too old most likely for the BridgeOS that's installed. You should use Shift-Option-Command-R, not CMD + R for recovery. That should install a later version of MAC OS (like Monterey). You can't change the startup security to boot off USB till you have the OS installed and created an Admin account.

I wonder what will happen to all these T2 systems when Apple decide to shut down their end for recovery. I setup all T2 systems to enable boot from USB.

[sajidmirza]

Catalina is too old most likely for the BridgeOS that's installed. You should use Shift-Option-Command-R, not CMD + R for recovery. That should install a later version of MAC OS (like Monterey). You can't change the startup security to boot off USB till you have the OS installed and created an Admin account.

I wonder what will happen to all these T2 systems when Apple decide to shut down their end for recovery. I setup all T2 systems to enable boot from USB.

yeah i have done that too,now its sonoma but still behaves same.reballed T2 chip but of no change
Thanks though

[rui4892]

Good morning, I have one of these machines on the bench, model A1862, with the same symptom mentioned in the initial post, that is, the logo appears and when it starts filling the bar the machine turns off.
This symptom only occurs with the screen connected to the machine, and occurs after the machine's overall consumption reaches 210W.
Without the screen and using a USBC-HDMI adapter the machine is completely usable although the fans are accelerated. In this case, the machine's consumption is around 70-80w.
I'm currently considering replacing the power supply...any suggestions from colleagues are appreciated.

[rui4892]

Good morning, I have one of these machines on the bench, model A1862, with the same symptom mentioned in the initial post, that is, the logo appears and when it starts filling the bar the machine turns off.
This symptom only occurs with the screen connected to the machine, and occurs after the machine's overall consumption reaches 210W.
Without the screen and using a USBC-HDMI adapter the machine is completely usable although the fans are accelerated. In this case, the machine's consumption is around 70-80w.
I'm currently considering replacing the power supply...any suggestions from colleagues are appreciated.

Good morning. The problem is solved. After reading somewhere that it could be a memory problem, I opened the equipment and tested module by module. It has 4 sticks of 32GB each. I cleaned both the RAM and the slots with isopropyl alcohol and tested one at a time. In the end, they all worked and the machine is fully functional with all the RAM (128GB)... The strange thing about this and what still confuses me is that the problem of not loading MACOS and turning itself off only appeared with the screen connected to the equipment.