Resolved Red diodes OVTMP CPU A and OVTMP CPU B on cMP 5,1 mono 3,46 GHz

[Mic-M4c]

Hi fokls !

I hope you go well.

I was installing Sequoia on a cMP 5,1 mono-processor 3,46GHz with OCLP 2.2.0.
While configuring some preferences, the Mac Pro suddenly shut down with those 2 red diodes flashing : OVTMP CPU A and OVTMP CPU B.

PSU diode and 5V STBY are not flashing

Any idea, suggestion, help ?

Thank you 🙏

Here are some pictures and one video :

20250221_171545.mp4

 

[Mic-M4c]

After 30 min outside (16°C in Paris), the Mac Pro restarted but shut down after 30 seconds

 

[tsialex]

Install a known working PSU, see if changes. If not, could be the CPU tray, backplane or even both. Time to test each part with a known working Mac Pro.

 

[Mic-M4c]

Hi Alex,
I guess PSU = Power Supply ?
D'ont you think it's the thermal paste on the processor which is defective ?

 

[tsialex]

Hi Alex,
I guess PSU = Power Supply ?

Yes.

D'ont you think it's the thermal paste on the processor which is defective ?

No - when the hardware is defective the processors are cool and OVTMP LEDs are lit.

30s is absolutely nothing for the thermal mass of the Xeon/Heatsink combo.

 

[Mic-M4c]

Ok
It sounds a bad news 😥

 

[Mic-M4c]

Hi folks,
my problem seems fixed, and you know how ? Simply by placing the Mac Pro vertically ! 🙈
Sequoia 15.2 is now perfectly installed and functionnal.
Indeed, I have placed the Mac Pro horizontally while changing my graphic card and the problem appeared.

 

[Macschrauber]

Use a tool like Macs Fan Control and show the temperatures. Especially Northbridge die and heatsink.