820-3437 black spots left side only

[gadgetfix]

Hey all. a1466

History: waterdamaged

- ultrasonic cleaned
- inspected under micro scope

everything seems ok but i have a problem with lcd backlight. it seems to have waves/black spots. it only come half way on the lower left. Is it possible to fix?

 

[JohnB8812]

Check LED returns on the LCD connector and their corresponding resistors and traces for continuity

 

[dukefawks]

No need to check the resistors, just diode mode all the LED return pins on the LCD connector. They should all read the same. Could be corroded connector/resistor/trace or LP8550.

 

[gadgetfix]

No need to check the resistors, just diode mode all the LED return pins on the LCD connector. They should all read the same. Could be corroded connector/resistor/trace or LP8550.

i measured all 6 pins they are all around 626~631

no sign of corrosion - water was more on the top side of board + the other end so i suspect it would be LP8550.
I will replace and report back.

Thanks for your help.

 

[dukefawks]

No use in replacing it if diode mode reads ok. Tried a known good LCD?

 

[gadgetfix]

disaster. changed lp8550 now no power. i will replace another one.

 

[gadgetfix]

cry me a river. had LP8550 mounted upside down. soldered it right way now boots but no blacklight? wonder why?