820-2850 no backlight

[raainxx]

Liquid spill on the board near U9000 i clean the board with ultrasonic, i remake solder of U9000.
I change the fuse F9800 and Q8608, but always no backlight. i check the connector of lcd for short, but i don't see anything.
Q8606 and F9800 are dead when i plug the screen.
can you help me please?
thanks

 

[dukefawks]

Check for short with LCD connected

 

[raainxx]

Ok i have really a short in the LCD, i change Q8608 again and i have BCKLIGT_EN_DIV= 12,08V and LCD_BCKLT_FUSED= 12,50V
PPBUS_S0_LCDBKLT_PWR=0,806V i don't understand why, the screen is not plug, the impedance of PPBUS_S0_LCDBKLT_PWR is 3K7 ohm.

 

[dukefawks]

Without LCD plugged in there will never be backlight voltage. Fix the short, probably bad cable or bad LCD.

 

[raainxx]

I try with a good LCD and i have always PPBUS_S0_LCDBKLT_PWR=0,3V

 

[dukefawks]

Do you even have an image? Voltages on Q9806?

 

[raainxx]

yes the image is dark but with flashlight i see.
BCKLIGT_EN_DIV= 12,08V
LCD_BCKLT_FUSED= 12,50V
PPBUS_S0_LCDBKLT_PWR=0,3V

 

[dukefawks]

Was that tested with LCD connected?

Voltages on Q9807 pin 2 and 5. LCD must be connected of course.