820-00165 3V instead of 3.3V on PPVRTC_G3H. DEAD CPU?

[SolderFungus]

Hi.
I have a board with PM_SLP4 missing.
PPVRTC_G3H is at 3V and not 3.3V Is this indicative of a dead CPU/PCH?
Signal is coming from U0500. I'm not aware of any steps that comes before that.

18.5V 0.021A from PSU
PPBUS_G3H 8.59V

 

[2informaticos]

PPVRTC_G3H comes from U1900 and 3V is good enough.

Do you get 3V3_S5/SUS?

 

[SolderFungus]

Oh I see. I struggle to see when a signal is inbound or outbound on the schematics :S

3V3_S5 2.908V
PP3V3_SUS 2.90V

Seems like all voltages are slightly off.

 

[2informaticos]

3V42_G3H is good?

 

[SolderFungus]

Yes. 3V42_G3H 3.4V

 

[2informaticos]

Try with 2K2 resistor instead of 10 ohm for R7563.
You can also try 9K1 instead of 10K for R7561.
Playing with feedback resistors, you can adjust correct 3V3_S5 voltage.

 

[SolderFungus]

Replacing the resistors restored voltages and I now have a booting device!
I had already replaced the U7501 and measured DIODE mode up against OBDATA and everything checked out. I would never have been able to fix this board without your guidance.

Thank you! 2informaticos!

 

[2informaticos]

Glad to hear your problem is solved.