820-2936-B Rails pulse (except PP3V42 and PPBUS)

[2informaticos]

Something pulls down PM_SLP_S3_R_L, or bad R7978...
Remove Q7802/12, Q7931 and Q5300.
One of them bad, has leakage, or corrosion.

 

[djdblaster]

Okay, removed Q5300, PM_SLP_S3_L seems normal now. (0.462).

Can I start without Q5300? I doubt since it's PBUS Voltage Sensor?

 

[2informaticos]

You can try at least.
Better to solve the problem there first; change Q5300.

Do you get 3.3V at PM_SLP_S3_L now?

 

[djdblaster]

Yes, PM_SLP_S3_L has 3.3V. Laptop starts, fan spin. Q5300 needs to be taken care of.

How did you find out that something related to PM_SLP_S3_R_L could be bad?

 

[2informaticos]

In base of your measurements...

 

[djdblaster]

Ah okay, so based on R7978 pin 2 which is PM_SLP_S3_R_L. That's why some other signals such as CPUVCCIOS0_EN were lower than on known good, but I've put it aside for now.

 

[djdblaster]

Laptop starts now, draws around 700mA, fan spins, but also beeps one time every few seconds. No image or chime.

I tried different RAMs.

 

[2informaticos]

Try new BIOS file...

 

[djdblaster]

I did. No luck

 

[djdblaster]

Any other ideas? Maybe another BIOS chip from same board?

 

[2informaticos]

Monitor CPU VCORE.
Do you see any drop from 1.1-1.2V to 0.75-0.85V after few seconds?

Where did you get the BIOS dump?
BIOS chip from other board will have dirty ME region, but should serve for test...