820-3435 1V PPbus

[iClub]

This mac had short C7131, I replaced it but with no result.
Replaced Q7130, U7100, AND Q7180.
When I removed F7140, there is no voltage on either side.

PP3v4_g3h 3,4; PPbus ~0,92V; PPDCIN 16,65V

 

[2informaticos]

What is the actual voltage at C7131?

 

[iClub]

0,741V

 

[2informaticos]

Post U7100 basic voltages...

 

[iClub]

1- 0,11V
2- 16,22V
3- 4,32V
9- 0,33V
12- 3,4V
13- 3,4V
14- 3,38V
15- 0,050V
17- ~0,935V
19- 5,043V
20- 5,031V
27- 0,960V

 

[2informaticos]

Now post Q7180 voltages.
Use R7180/85 ast test points.

 

[iClub]

2-16,68V
6 - 0,948 V
3- 6,77 V
4- 0,419 ~ 0,968V

 

[2informaticos]

Change Q7180, is bad.
Be sure no short to ground at R7120.

 

[iClub]

replaces it, same result.

Certifique-se de que não haja curto para o aterramento em R7120.

There is no short.