MacBook 820-02020-A with cycling voltage , Liquid Damage

[EcWeb.L.]

Changing uc710 wouldn't make a difference ? Any way to go further with the diagnosis or i should consider this a dead board?

 

[2informaticos]

Your low reading on 3V3_S2 denotes something was already damaged there.

 

[EcWeb.L.]

I am sorry but ,with the little knowledge i have, i'm not sure if i understand correctly . The damage could be in the trace itself or the cpu , i'm left with little to do about it . Right?

 

[2informaticos]

CPU is the most sensitive component connected there.
Is still possible to be other IC affected, but less probable.

 

[EcWeb.L.]

last update : I've checked the other IC's . All good.
I've put back everything on the board ( also LC710) and the voltage mantained on 20v for about a minute . I've noticed that i have a good 3.36v on PP3v3s2.
After this one time the machine went back to cycling voltage.

Could this give any clue or it's always about CPU?
Also , changing cpu could be of any use? Because i could tell the customer to go into a repair shop that has the right tools for this type of job.
Or should i just tell him that this is a lost case?

thanks for the feedbacks you've given me in these days

 

[2informaticos]

Something else affected by liquid.
Can be 3V3_S2 power supply problem.
Just in case, remove CC719.

 

[EcWeb.L.]

Removed CC719 , back to cycling immediately, peaked at 0.190mA then restart.

Checked CC720

-P3v3S2_VOS is 0.298 and it should be 0.442

Checked RC712

-P3v3S2_FB_R is 1.824 , it should be OL

 

[EcWeb.L.]

dead board not worth the time investment?

 

[2informaticos]

Very likely...

Diode mode reading at 3V3_S2 good, after removing RD810?

 

[EcWeb.L.]

removed RD810 , still the same .

 

[2informaticos]

Liquid damage boards may cause nightmares.
You may have corrosion under some BGA chips.

 

[EcWeb.L.]

all right , thx for the support . I'll comunicate it to the customer.