Motherboard or CPU

[HFultzjr]

I have a Dell Optiplex 7020 MT
i5 8GB ram SSD
It has a thermal shutdown issue. Won't run for more than 10-15 seconds.
The one time I got into the BIOS logs, it showed thermal shutdown issues, this time it ran for about 45 seconds.
Things I've tried/tested:
Removed everything but monitor, USB Keyboard, USB Mouse. These 3 are mine and known good.
Thermal paste, reset heatsink, fan works. Heatsink barely gets warm before shutdown.
Thermal paste and heatsink are contacting as paste is being spread out.
Tried different heatsink, same issue.
Removed Ram, a few beeps then same issue.
Different known good power supply.
Replaced CMOS battery.
No bulging capacitors that I can see.
Nothing on board seems to get hot.
It seems like it is a sensor, as nothing gets really hot. Only stays on 10-15 seconds.
Without heatsink or fan, CPU gets hot, but not enough not to touch.
Motherboard or CPU.............your thoughts.

 

[Larry Sabo]

Sounds like a MB issue with failing circuit that senses/monitors cpu temp. Don't know if that could be within cpu itself but if swapping cpu doesn't fix it, it's obviously a defective MB.

 

[HFultzjr]

Sounds like a MB issue with failing circuit that senses/monitors cpu temp. Don't know if that could be within cpu itself but if swapping cpu doesn't fix it, it's obviously a defective MB.

Thanks Larry.
I have another CPU to test, but afraid to put it in a possible bad board.
There not very much, so I guess if I blow it, no big deal.
With my luck, I'll pull it out of a good machine I have for sale, blow it, and someone will want the machine ASAP..........................lol.

 

[Porthos]

I would have replaced the computer before I did half of what you did.

 

[lan101]

I would have replaced the computer before I did half of what you did.

Yeah I guess maybe I'm just lazy...but if I can buy a good conditioned one for $100-$150 I'm not putting in a ton of effort to go down a rabbit hole. When I see this type of issue I just assume it's a motherboard and move on to the solution.

 

[lan101]

At the same time I appreciate the efforts of the guys that do go that extra mile because many times it will teach us something too.

 

[Larry Sabo]

Motherboard or CPU.............your thoughts.

I forgot to mention that I had a customer with an overheating system whose MB I took to my colleague who does my MB repairs. He looked at the board, traced a few circuits in his head, and said, "This transistor looks a little discoloured." Changed it, and the problem was solved.

 

[coffee]

I have a Dell Optiplex 7020 MT
i5 8GB ram SSD
It has a thermal shutdown issue. Won't run for more than 10-15 seconds.
The one time I got into the BIOS logs, it showed thermal shutdown issues, this time it ran for about 45 seconds.
Things I've tried/tested:
Removed everything but monitor, USB Keyboard, USB Mouse. These 3 are mine and known good.
Thermal paste, reset heatsink, fan works. Heatsink barely gets warm before shutdown.
Thermal paste and heatsink are contacting as paste is being spread out.
Tried different heatsink, same issue.
Removed Ram, a few beeps then same issue.
Different known good power supply.
Replaced CMOS battery.
No bulging capacitors that I can see.
Nothing on board seems to get hot.
It seems like it is a sensor, as nothing gets really hot. Only stays on 10-15 seconds.
Without heatsink or fan, CPU gets hot, but not enough not to touch.
Motherboard or CPU.............your thoughts.

Bios updated?

The startup chip monitors the temps in a lot of models. It could be the circuit that corresponds to the temps and works in conjunction with the startup chip. If you want to pursue it further take a pic or jot down the startup chip model number here. Ill look up the specs and see what the voltage for the temp sensor should be. If the startup chip is reading a incorrect voltage it would shutdown the computer.

 

[HFultzjr]

Bios updated?

The startup chip monitors the temps in a lot of models. It could be the circuit that corresponds to the temps and works in conjunction with the startup chip. If you want to pursue it further take a pic or jot down the startup chip model number here. Ill look up the specs and see what the voltage for the temp sensor should be. If the startup chip is reading a incorrect voltage it would shutdown the computer.

BIOS is updated. I worked on this a few months ago and that was one of the things I did, along with Win 10.
Thanks for the offer, but I have another motherboard coming in. Not worth spending too much time on this, but right now with Covid-19 going on, I'm very slow. I have time to play and learn.
Thanks everyone.

 

[HFultzjr]

Replaced motherboard.............problem solved.
Thanks everyone.