820-3115-b no power

[syslan]

hello. I have a 3115-b motherboard. Apparently no corrosion damage.

Green light on charger after about 10 seconds, pulling 0.04A.

missing PP3V3_S5 (0V) without short circuit to ground



Voltages for U7200:
16 - 12.29V
13 - 2.12V
3 - 0V
8 - 0V
17 - 0.4V
6 - 0V

VOLTAGES for U7941:
4 - P3V3S5_EN_L = 2.9V
3 - 0V
6 - 0V
2 - 0.75V


Any Help?

 

[2informaticos]

First, PPBUS_G3H is incorrect?
Did you test with board alone on the desk?

Post the exact 3V42_G3H and SMC_RESET_L.

 

[syslan]

"First, PPBUS_G3H is incorrect?"
It's a bit low right?

I'm testing just the board with nothing connected.


3V42_G3H (F7040) = 12.29V stable
SMC_RESET_L = 2.16V
When I measure SMC_RESET_L something weird happens. The multimeter goes up from 2.16V to 2.5V slowly

 

[2informaticos]

Low voltages.
I suspect a problem with 3V42_G3H power supply.

"3V42_G3H (F7040) = 12.29V stable"
Why don't you post correct information?
What did you see common between L6995 and F7040?

 

[syslan]

sorry, I was wrong.
PPBUS_G3H = 12.29V

I changed u6990 and u7941 and everything is the same

 

[2informaticos]

You still didn't post expected value.

Please, post actual 3V42_G3H and all U5010 voltages.

 

[syslan]

you're right

3V42_G3H = 3.48V

U5010 voltages:

1- 3.48V
2 - 0V
3 - 0V
4 - 0V
5 - 0.15V
6 - 0.05V
7 - 0V
8 - 0.08V

 

[2informaticos]

"3 - 0V"
Check solder and trace...

 

[syslan]

I post the new values


3V42_G3H = 3.48V

U5010 voltages:

1- 3.48V
2 - 0V
3 - 3.48V
4 - 2.85V
5 - 2.09V
6 - 2.47V
7 - 3.47V
8 - 3.30V

 

[2informaticos]

Pin 5 still no good; just around to the low limit of high level required.
Remove U5010 and check if goes higher.
You can force 33-47K instead of 100K, for R5000.

 

[syslan]

I removed U5010 and it's still low (2.09)

Then swap R5000 for a 33k resistor.

now pin 5 (SMC_RESET_L) = 2.8V.

but everything is the same

 

[2informaticos]

2.8V is enough for high level, but not a normal value.
There must be something else affected.
Remove R7000 and check if goes higher to 3.3V.
If still the same, remove U5010 and check again; you may need to change it.
Last option, reball/change SMC.

BTW, do you get 3V3_S5 now?

 

[syslan]

I removed R7000 and U5010 and checked if it goes up to 3.3V but it doesn't go up. It's the same. I'll proceed with the SMC I guess.

I'm still without 3V3_S5.
3V3_S5 = 0.06V

 

[syslan]

update...

I changed SMC and now I have the following values:

3V42_G3H = 3.48V
PPBUS_G3H = 12.57V
SMC_RESET_L =2.6V
3V3_S5 = 0V
but when i remove U5010 now if it goes up to 3V (SMC_RESET_L =3V).

for this reason also change U5010. but still the same (2.6V)

 

[2informaticos]

Clean J5100 pads, just in case.
Do you have 3.4V at pin 1 of R5000 and pin 3 of U5010?
Still forced with 33k?

 

[syslan]

I had the resistor as it was originally and I have 3.48V on pin 1 of R5000 and 3.48V pin 3 of u5010. I changed it to 33k and this happens:

With U5010 already on
R5000 (pin1): 3.48V
R5000 (pin2): 2.70V

U5010 (pin5): 2.7V
U5010(pin3): 3.48V

when i remove U5010 these are the values.

R5000 (pin1): 3.48V
R5000 (pin2): 3.3V

U5010 (pin5): 3.27V
U5010(pin3): 3.48V


j5100 is clean

 

[2informaticos]

Strange behavior, but 2.6V is good enough to start the SMC.
Check SMC_PM_G2_EN, if pulses at least.