820-3332 in S0 but no All_sys_pwrgd

[PhilipC]

No liquid damage green light turns orange
G3h 12.55v,
Pp5v and p3v3 all present down to s0.
All_sys_pwrgd 0.070 not shorted to gnd

What makes all_sys_pwrgd?

 

[2informaticos]

Post voltages for pins 1, 5, 7 of Q7950.
Not really needed, it could be removed.

"All_sys_pwrgd 0.070 not shorted to gnd"
Diode mode, or voltage?
Too low value for diode mode.
You can remove R7963-9, one by one, until ALL_SYS_PWRGD comes high.
Do NOT remove R7967; be sure is good.

 

[PhilipC]

Q7950
Pin1 0.746v
Pin2 0.706v
Pin3 0.777v

All_sys_pwrgd 0.70v, 0.430 diode mode red on ground

R7697 good 10k

When removed R7968 all_sys_pwrgd goes 3.3v and boots

 

[2informaticos]

Do you get 1.5V at L7770?
Change U7710...

 

[PhilipC]

changed U7710 pins of l7770 are now fluctating between 1-2.4v and machine tries to boot when in the 1.5v range then shutsoff when above 1.8v

 

[PhilipC]

All the resistors for u7710 circuit measure correct and changed all caps to be safe still same behavior
Changed U7710 again to be sure still same behavior

 

[2informaticos]

Did you get 1.5V before changing U7710?

 

[PhilipC]

It was steady 2v

 

[2informaticos]

2V no good, that was the reason to pull down ALL_SYS_PWRGD.
Check R7780/81, look at the formula...

 

[PhilipC]

Yeah what i dont understand is why its giving up to 2.4v,
all the resistors are good

 

[2informaticos]

Adjust one of these resistors to get the correct 1.5V output...

 

[PhilipC]

Removed L6201 got steady 1.5v
C6211 was causing the problems even though it was measuring and looked fine

All fixed thank you