MacBook Pro 13 2012 820-3115 no CPU v-core voltage

[ielectron]

Hi,
I have another MacBook Pro 13 2012 with v-core no power.
I have replaced U7400 with no luck measure on TONA 12.25v and TONB 12.06V
I measure this voltage on another working board and its below 1v.
I have tried also swap bios just to check no luck SMC reflowed nothing.
Board is not liquid damaged didn't find anything corroded. Voltage on other rails is okay.
Whats interesting FAN is not working 5V and FAN_RT_tach present.
I have suspected corrosion under PCH. Anyone have similar symptoms before on this boards ?

 

[2informaticos]

Do you get ALL_SYS_PWRGD?

 

[ielectron]

I getting 0.02V on ALL_SYS_PWRGD

This what I getting on Q7950
VMON_Q2_BASE - 1.06v
VMON_Q3_BASE - 1.5v
VMON_Q4_BASE - 1.05v
S0PGD_C - 3.27v

 

[2informaticos]

You cannot get VCORE without ALL_SYS_PWRGD.

Q7950 could be safely removed, is redundant.
Check which power supply summed through R7963-63 is the culprit.
Be sure to get 3V at pin 1/R7967.

 

[ielectron]

Laptop fixed Q7950 was faulty. Thanks 2informaticos for help.