Lenovo Yoga 2 Pro trouble

[razadom]

Hi all
please who can help me. I have trouble with this laptop. The computer is boot normaly
but no signal ( video+backlight) on lcd screen. I connect this on external screen with hdmi and there was video. I download a dump from this forum and write it. The result is the same. No video on internal LCD.

[KvnTM]

Re: Lenovo Yoga 2 Pro trouble

I attached the schematic.

First thing to measure would be the lid switch:
Measure for MXLID_N on R218. Should be 3.3v when lid open and 0v when closed.

LCD Panel voltage:
Measure +3VDX_EDP on JP14 (Pin 18..21). Should be 3.3v.

LCD Backlight:
Measure LCD_BL_EN_R on JP14 (Pin 32). Should be 3.3v when lid open.
LCD_PWM_BKLT on JP14 (Pin 33) is the PWM control line for the backlight.
V_BL_LED on JP14 (Pin 36..39). Should be 19V.