Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

christiann

macrumors 6502
Original poster
Jun 7, 2020
449
167
North America
Hi,

My MP 4,1 has been replaced by a new one. It’s been working fine for a few weeks until I just got the CPU overtemp light and now it won’t boot. Thoughts?
 

tsialex

Contributor
Jun 13, 2016
13,455
13,601
Lot's of possibilities:

  • defective CPU tray
  • CPU tray Northbridge heatsink push-pins
  • defective PSU
  • defective backplane

I'd start checking the heatsink push-pins, then testing the CPU tray with a working Mac Pro, then the PSU. After confirming that both the CPU tray and the PSU work flawlessly, I'd replace the backplane.
 

christiann

macrumors 6502
Original poster
Jun 7, 2020
449
167
North America
Lot's of possibilities:

  • defective CPU tray
  • CPU tray Northbridge heatsink push-pins
  • defective PSU
  • defective backplane

I'd start checking the heatsink push-pins, then testing the CPU tray with a working Mac Pro, then the PSU. After confirming that both the CPU tray and the PSU work flawlessly, I'd replace the backplane.
Just replaced CPU tray and same issue. I also just replaced the thermal paste. I’m thinking of buying a 3,1 for $50 temporarily while I get this one fixed.
 

tsialex

Contributor
Jun 13, 2016
13,455
13,601
Just replaced CPU tray and same issue. I also just replaced the thermal paste. I’m thinking of buying a 3,1 for $50 temporarily while I get this one fixed.
I'd buy the cheapest working early-2009 to mid-2012 that you can find, since you will need a working one to test the parts of your defective one.

You can't test anything with a MacPro3,1, but if you need work done…
 

christiann

macrumors 6502
Original poster
Jun 7, 2020
449
167
North America
I'd buy the cheapest working early-2009 to mid-2012 that you can find, since you will need a working one to test the parts of your defective one.

You can't test anything with a MacPro3,1, but if you need work done…
The problem is everyone in my area wants $150 for a 2009 MP. I just need to flash and sell some graphics cards so a 3,1 is fine for now until I get a deal on a newer one.
 

TzunamiOSX

macrumors 65816
Oct 4, 2009
1,057
434
Germany
Lot's of possibilities:

  • defective CPU tray
  • CPU tray Northbridge heatsink push-pins
  • defective PSU
  • defective backplane

I'd start checking the heatsink push-pins, then testing the CPU tray with a working Mac Pro, then the PSU. After confirming that both the CPU tray and the PSU work flawlessly, I'd replace the backplane.
Bad thermal paste or a small distance between cpu die and heatsink is also possible.

Edit: sorry read to late. Did you used the same cpu? Single or dual machine?
 
Last edited:

christiann

macrumors 6502
Original poster
Jun 7, 2020
449
167
North America
Bad thermal paste or a small distance between cpu die and heatsink is also possible.

Edit: sorry read to late. Did you used the same cpu? Single or dual machine?
I used a different CPU. It’s a single. I bought a 3,1 and it’s working fine. Every 4,1 I have bought from the same person with the same issues
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.