lenovo x240 Screen Backlight not present

[salamonnorbert]

Hello people of Badcaps!

Facing a problem since weeks and I got no idea how to fix this one.

Laptop: lenovo x240 with NM-A091 motherboard

We tested the screen baklight and all works. Ribbon cable is good it is clearly some sort of motherboard issue.

I do not want to fix the board if an alternative solution is possible with a bridge on the screen. (Seen some videos of people bridging LED_PWM and LED_IN) but I don't know how to do that with this particular panel.

Any advice? Thanks in advance

P.s: there is a weird mark on the old screen connector. Can it be related?

[mcplslg123]

Re: Screen Backlight not present

Measure voltage and resistance on pin 12/13/23/24/26 of LCD Connector. Be careful while measuring.

[salamonnorbert]

Re: Screen Backlight not present

Measure voltage and resistance on pin 12/13/23/24/26 of LCD Connector. Be careful while measuring.

Thanks a lot for replying!

0v at every pin wich you suggested. The multimeter is not faulty. What do you suggest?

[mcplslg123]

Re: lenovo x240 Screen Backlight not present

Its very unlikely. I doubt your measurements. Are u sure about pin 26?? You are supposed to get +19V there. Btw, pin26-29 are together. Pin 13-14 is LCD VCC and it is expected to get 3V there. Check F3 as well.