A1707 820-00928 no display

[TBFix]

I have a board with no display I have tried the screen on another board and the screen is fine.

I have tried bios downloaded from here but still the same. board draws 1.2a . I have held a light to screen and cant see anything so I dont think its backlight .
Any ideas where to start with this.
Im getting 0v on PP3V_S0SW_LCD
and 5v on PP5V_S0_ALSCAM_F
0v on PP5V_S0SW_LCD

 

[2informaticos]

Any history available, liquid sign?

First of all, check for USB activity.
Many times explained on the forum, how to assure such activity...

 

[TBFix]

No sign of liquid spill.. Usb activity present. I tried a different bios dump and now I am getting
5v on PP5V_S0SW_LCD and PP5V_S0_ALSCAM_F
3.3v on PP3V3_S0SW_LCD
0v on PPVOUT_S0_LCDBKLT.
I am getting external output to monitor also.
0v on EDP_BKLT_EN from U9800
DP_INT_HPD_R 4.3v
LCD_IRQ_L. 0.2v
BUF_EDP_PANEL_PWR_EN 3.4v
EDP_AUXCH_C_P + EDP_AUXCH_C_N reading 0v on diode mode can U9850 be changed for new or is it programmed?

 

[2informaticos]

U9850 has no firmware...

 

[TBFix]

Yeah swapped with one from 3787 and seems to be fine

 

[NIKHIL@1997]

U9850.....Is it possible to reprogram....?

 

[2informaticos]

"U9850 has no firmware..."