820-3332 - Quarter Fan

[menatwork]

I got this board with quarter fan spin.
PP5VS5 and SUS = 5V
PP3V3S5 = 3.3V
PP5VS3 = 0.54V

PMSLPS4 and S5 = 3.32V and 3.35v

any hint?

 

[2informaticos]

If PM_SLP_S4_L is stable 3.3V, then all S3 voltages should be present too; check that.
PM_SLP_S3_L stays low, or pulse high at least one time?

 

[menatwork]

Pulsing:
goes 3.3V and zero.

 

[2informaticos]

Then S0 voltages should pulse too; maybe not the CPU coils.

"all S3 voltages should be present too; check that."

What about pins 7 & 3 of U7950?
ALL_SYS_PWRGD pulses at least?
Did you try SMC bypass?

 

[menatwork]

pins 7 & 3 of U7950 = 0V
ALL_SYS_PWRGD Pulsing in cycles as well.

PP3V3_S0 = 3.3 and zero (in loop)
PP3V3_S3 = 3.2V and zero (in Loop)

 

[2informaticos]

Check if R7402/03 are good.

 

[menatwork]

Both looks fine: 182K

r7403 =
pin 2 = 12.56V
Pin 1 = 12.44 to 12.30V (loop)

R7402
Pin 2 = 12.56V
Pin 1 = 12.44 to 12.30V (loop)

 

[2informaticos]

TONA/B pins should drop to 0.5V aprox, when CPU power supply works.

Is PM_SLP_S4_L stable high for sure?
In such case, S3 voltages should be stable too.

 

[menatwork]

For some reason, PMSLPS4 is doing the same thing: 3.3V and 0V (loop)

 

[2informaticos]

"Did you try SMC bypass?"