[SOLVED]820-2532 EFI Temp errors above limit

[jadao]

This machine had been given to me and sitting there for few months, it had 0.33V on 1.05V MCP S5 rail. I replaced C7771 and all went good. Chimes and boot ok no lag no heat. No water damage, this board is intact.

I decided to run EFI just for the heck of it and found these 3 Temp errors all reading above high limit according to hardware profile:

Temp (TG1H) - Left Heat pipe / Fin Stack Proximity Temp (test 1) / Range [15-80]°C / Reading reported 128.000°C
Temp (TN0D) - CPU Vcore voltage (test 1) / Range [15-100]°C / Reading reported 128.000°C
Temp (TN0P) - MCP Proximity (test 1) / Range [15-75]°C / Reading reported 128.000°C

They all report the same 128.000°C value, should I look only to U5550 and U5500?

 

[dukefawks]

First see if it is receiving 3V on pin 1. Then pull it and see if ASD now reports an IO error on those sensors and no over temp. Then it is possible the chip is just bad.

 

[jadao]

3V was present on pin 1 of u5550 and u5500.
I removed suspected U5500 and noticed no change, still 3 same errors TG1H TN0D TN0P. So I made assumption the chip is bad or the heatsync sensor bad or both.
I decide to removed U5550 and noticed 3 new errors TG0H TG0P TG0T So I made assumption this chip is good.
Let's swap those chips and see what happen: No more errors!

Happy it's fixed but this makes no sense to me maybe something to do with the heatsync when I removed it to check the little sensing circuit underneath...

Thanks Duke you can please mark this one solved!