A1466 820-00165-A no backlight


I have an A1466 820-00165-A with no backlight, that has no liquid contact. It just stoped working. i´ve tried with a working LCD and it has no BL.
The FL7700 is ok and has 8.5V, R77989 has 8.5V, Q7707 has 8.2V on LCDBKLT_EN_L, and 3.3V on BKLT_PLT_RST_L, but on Q7707 i have 0V on EDP_BKLT_EN.

Can you help me?
Last edited:


Staff member
EDP_BKLT_EN must be high, to get backlight.
Try PRAM reset 2-3 times.
If still the same, force pin 3/Q7707 to ground and test again.

Check diode mode to ground on both pins of D7701.
Be sure XW7720 is good.
Post BKL_EN/PWM levels.
Sorry, i was measuring them without lcd connected.
Here are the correct readings:

BKL_PWM = 1.46V
BKL_EN = 2.84V"

EDP_BKLT_EN 3.3V on Q7707 but no BL


Staff member
"BKL_PWM = 1.46V"
Did you try PRAM reset 2-3 times?

If still the same, remove R7704 and run a wire from C7704 to R7715.


Staff member
"Try full compatible LCD assembly"

Keep BKL_EN/PWM joined for testing puropse.

Check all return resistors and compare diode mode to ground.