MSI MAG Z390 Tomahawk BIOS temp, allways at 0ºC and CPU goes protection 800Mhz

[foshland]

Hi to all, my motherboard (bought second hand as faulty, but now working after cleaning the ram slots) have a strange failure that shows 0 Celsius degrees in BIOS, because of that, the CPU goes to protection mode and gets stuck at 800Mhz.

Since its a 8-9 Intel generation, I know the CPU temp is the hottest temp of the cores (as i have read in intels documentation) so its not a diode or sensor on the board.

External temperature (motherboard temp) is working OK, 27ºC more or less

In windows, all the software I have tested shows correct the Core temps

Have tried with 3 diferent CPUs, a Celeron, a i3 and a i7

Have tried with 3 different BIOS files, all from MSI webpage

If I dissable intel adaptative thermal monitor option in BIOS, temperature still at 0C but CPU now works OK in BIOS and windows (all core, no problem at all)

No bent pins on socket, all clean motherboard, no visual defects.


I have done benchmarks, enabled XMP, all seems OK, I can work like that, but I would like to fix it if possible, any clue what is going on?

Thanks a lot

[foshland]

Ok, I made a wrong assuption and yes, there is a smd NTC under the CPU, in the space inside the socket, so ill work in that direction.

As far as I could check, the resistor and the connection to the I/O chip is ok, have to check a pair more of details and will post if there is any good news.

Thanks a lot