820-3476 stuck on 4V

[huzeafa]

hello guys , have got an 820-3476 that is stuck on 4v. I have replaced the ISL but still no difference , and I do not have a short to ground. please help

 

[2informaticos]

Do you get Magsafe amber light?
Check exact resistance between pins 17/18 and 27/28 of ISL6259.
Also post basic voltages for U7100; pins 1, 2, 3, 9, 12, 13, 14, 15, 19, 20, 27.

 

[huzeafa]

thank you for your time
yes I get the light

resistance 27/28 =020.4
resistance 17/18 =003.6
pin 1=0.04
pin 2=20v
pin 3=4.8
pin 9=0.30
pin 12=3.4
pin 13=3.399
pin 14=3.399
pin 15=0.061
pin 19=5.4
pin 20=5.5
pin 27=19.83

 

[2informaticos]

Check R/C7125.

 

[huzeafa]

R/C7125 look okay , and I get the same PPBUS value of 4.8V , I had also replaced Q7130 but no changes

 

[2informaticos]

"R/C7125 look okay"
Did you replace them?
Solders and traces OK?

Do you have 3V at pin 6?
Check/replace components from pins 5, 7, 8.
If still the same, change ISL6259.

 

[huzeafa]

I get 3V on pin 6 but 0V on 5,7 and 8

 

[2informaticos]

Pin 6 is OK then.
I didn't ask about voltage on pins 5, 7 & 8.

 

[huzeafa]

what do you wish me to do ?

 

[2informaticos]

"Check/replace components from pins 5, 7, 8"

Did you replace C7125?
R7125 is 0 ohm for sure?

 

[huzeafa]

you are a star. Thank you so much, I replaced components from pins 5, 7, 8 and there you have it , PPBUS in its full glory , thank you so much