820-00165 WATER

[thomamagic]

hello
i have mainboard 820-00165 with problem after water damage
i have clean and laptop work 2 weeks
actually no boot, no light on charger

Problem is with ppbus_g3h

i have 1.4V on F7140 pin1 after remove F4140 but i have good diode value (0.1)
but on pin 2 i have 0.4 in mode diode but need 0.1

i have check around U7100 no water but i have replace it for be sure same problem

around U5000 no see damage components

please need your help

 

[2informaticos]

"but on pin 2 i have 0.4 in mode diode but need 0.1"
With F7140 removed???
STOP making wrong assumptions and put some logic on your job.
So simple like comparing with other board; in case you don't believe me!

You've changed U7100 without checking its voltages?
Which value made you took such decision?

Do you get 3V42_G3H at least?

 

[thomamagic]

i have this group for help for repair
on 3V42_G3H i have 3.41V

 

[2informaticos]

Ok, now post U7100 basic voltages; 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.

 

[thomamagic]

Pin 1: 0v
Pin 2 : 18v
Pin 3 : 4.9v
Pin 9 : 3.9v
Pin 12 : 3.41v
Pin 13 : 3.38v
Pin 14 : 3.37v
Pin 15 : 0v

 

[2informaticos]

What about the rest???

Please use 45W charger; or set 15-16V on lab PSU, if use it.
4.9V on ACIN may be too high and U7100 can stop to work; not sure, just in case.
Check if machine turns on in SMC bypass mode.

 

[thomamagic]

with 15V on lab PSU :
Pin 1: 0v
Pin 2 : 14.2v
Pin 3 : 3.9v
Pin 9 : 3.9v
Pin 12 : 3.41v
Pin 13 : 3.38v
Pin 14 : 3.37v
Pin 15 : 0v
pin 17 : 1.56v
pin 19 : 5v
pin 20 : 5v
pin 27 : 0v

 

[thomamagic]

I did a test in smc bypass mode and no fan is running, the machine remains at a standstill

 

[2informaticos]

"Pin 9 : 3.9v"
Check R7121/22 and their traces.

 

[thomamagic]

check but no traces visible
i have replace it and macbook works correctly
Thanks a lot you have perfect