A2338 820-02020 no backlight after liquid

[iMuhtaseb]

this computer came in for no backlight after liquid spill

PPVOUT_LCDBKLT is 0v
PP5V_BKLT_A is 5v
PP5V_BKLT_D is 5v
BKLT_EN_R is 1.8v coming MPMU
BKLT_SDA 5.1v
BKLT_SCL is 5.1v

PP5V_SW_LCD is 5v
PP3V3_SW_LCD is 3.3v

FP800 Fuse is OK

BKLT_SD is 12v; something is shutting down the backlight

I took the measurement of all legs of UP800 and compared them to flexBV; everything seems ok
nevertheless I have replaced it not once but twice with known-goods still same issue..

Kinda lost here since everything seems OK, what am I missing?

[iMuhtaseb]

Of course known-good screen was tested.. and a good LVDS cable too

[reformatt]

UP800 is only half of backlight circuit. UP800 communicates to another IC in the display via I2C and this isn't happening since BKLT_SD is not being pulled low.

https://logi.wiki/index.php/Backlight_Troubleshooting

Refer to BKLT_EN high but LCDBKLT_EN_L is not being pulled down

Terminology is slightly different due to an older model, but the fundamentals are the same.

[iMuhtaseb]

resolved, it turned out the PP5V_SW_LCD on the LVDS connector was OL.. a small jumper fixed the issue..