820-2936-B Does not turn on

[willie]

Magsafe connector does not turn on the led, but i have 3.46V in C5710; in U6100 pins 3 and 8 i have 0V, in U7200 pin 16 (VIN) i have 0.28V. I think i should have 12V instead that 0.28V.
When i take resistences to gnd in pin16 in the same U7200 it is ok.
What should i measure next?

 

[dukefawks]

Voltage on PPBUS?

 

[willie]

Do you mean PPBUS_G3H?

 

[dukefawks]

Yes .

 

[willie]

C3880 pin 1 0.20v

 

[dukefawks]

Was there corrosion around the ISL6259? Is ACOK present from 6259? SMC_RESET present?

 

[willie]

Corrosion I have not seen yet on the motherboard, But if anything on Magsafe Dc In Jack Power Board Cable 820-2565-a I see signs of corrosion and a burnt transistor.
I have tried with another Magsafe Dc In Jack Power Board Cable 820-2565-a.
Do you mean SMC_BC_ACOK pin 14? Not present.
Do you mean SMC_RESET_L i did the measurement on R7000 pin 1 3.42v.
U7000 pin 19 VDD 5.03v.

 

[willie]

No Title

 

[dukefawks]

That magsafe board is trash, use a known good one. Voltages on 6259 pin 2 and 3? Resistance to GND on PPBUS?