820 2936 b, No image

Noguinfor

New member
Hey ,

Working on 2936 b motherboard with liquid damage near SMC, U7000 and some asshole touch on Q9425 + Q3880!!
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initial the board don't turn on because PPBUS = 12.3V .. i replace U7000 + SMC and board was working well until i plug the battery. After that the board don't turn on and i noticed that U9480 was hot.. i found u9330 shorted replaced and short gone!! Now, the board start up normally but without image.. Not light on PENDRIVER!!

Q9425 + Q3880 replaced and i have a working board and test in diode mode all pin's and have same values compare with a working board!

PPBUS = 12.67V
PPVCCSA_S0_CPU = 0.9V
PP1V05_SUS - 1.05v
PP1V05_S0 - 1.055v
PPVCORE_S0_CPU 1.151

already replace a bios for new one with clean me no changes.. I don't touch in original one!

any suggestion ??

thank's
 

2informaticos

Administrator
Staff member
"board start up normally but without image"
What about backlight?

Surelly no USB activity?
Tested different RAM modules?

"PPVCORE_S0_CPU 1.151"
It should drop under 1V after few seconds; for a working board...

You must have corrosion problem still.
 

Noguinfor

New member
backing on this one,

i'm sure, i don't have activity on USB! Already tested diferent rams on 2 ram_modules!

PPVCORE_S0_CPU 1.151V don't drop to 1V ... keep on 1.151V.

already put the board on ultrasonic!! but no change. you have more ideas ??

thanks
 

2informaticos

Administrator
Staff member
So something happened when connected battery.
Battery bus is common for U7000 and SMC; one of them could be bad now.
Test resistance to ground at SCL/SDA, and voltage too (battery connected).
Does it charge the battery?
 

Noguinfor

New member
Ya, this one before i touch boot's well to operation system but with the battery problem!

SMBUS_SMC_BSA_SCL - 425v DIODE MODE
SMBUS_SMC_BSA_SDA - 425v DIODE MODE

I have 11.54V on PPVBAT_G3H_CONN with charger connect! It's normal PPBUS_G3H goes to 11.54V with battery and charger connect ?

i think the battery is charging, the light goes orange when i plug the battery and when i take off the charger the fan keep working!!
 

2informaticos

Administrator
Staff member
PPBUS_G3H should increase bit a bit, if battery is charging.
Once battery is fully charged (100%), PPBUS_G3H should go to 12.5V and magsafe switch back to green..
 
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