820-00928 - A1707 - No Backlight

[iFix]

When powered on the voltage on PPVIN_S0SW_LCDBKLT go up to 3.5v and comes back down like something is pulling it when it tries to shows backlight

 

[iFix]

SOLVED! C8462 was the issue

 

[2informaticos]

If PWM duty cycle changes when press backlight keys, denotes the PCH works good.
The LCD assembly doesn't receive correctly this signal, or you have a problem between U8400 and LCD assembly.
Check for reaction on SCL/SDA lines at same time with PWM signal.

 

[iFix]

All is good now works fine C8462 had internal crack which didn't show visually and also there was no short but while I was replacing the diode and other ICs it cracked and showed I just replaced it and it worked Thank you very much for your help