820-2879 logic board, green light/orange ok, NO JUMPSTART

Hey Guys,

I have an easy question for some expert.

I fixed an A1278 logic board, 820-2879 coming from water damage.

I first I clean it very well with sonification bath with professional solution and overnight deep bath into Isopropyl alcohol 100%, certified grade.

I replace the Intersil ISL6259AHRTZ, perfectly.

Now I have green light with MagSafe and orange light when connected to the battery.

The voltage at the starting pad "jumpstart" is ok, 3.35 volts.

When I'm going to short the pad I don't' have any power on. (No fan Spin)

The same happen when I short the #5 pin of the keyboard connector to the ground.

I wondering if could be the GPU, that need to be reflow.

Before check all the S0 voltage and so,

Do someone have some advise for me?

Which voltage I need to check first?

Why if I have the correct voltage at the pin pads , I can jumpstart the logic?

best