dell latitude 5400 no display after dell logo

[dqtech]

i have issue with this laptop no display (do have backlight) after dell logo...but it only happen sometimes when turn on the laptop....when it hapen, i connect to hdmi and display is normal on external monitor....sometimes will give normal display....

board number EDC41 LA-G892P Rev 1

[dqtech]

here the video

[mon2]

Isn't there a hot key to make use of the external monitor? Check if your keyboard is working ok or maybe the key is stuck. If the external HDMI is working, disconnect it now and see if the internal display switches ON. Can you also apply a torch / flashlight onto the screen? Maybe a backlight fault?

[dqtech]

Isn't there a hot key to make use of the external monitor? Check if your keyboard is working ok or maybe the key is stuck. If the external HDMI is working, disconnect it now and see if the internal display switches ON. Can you also apply a torch / flashlight onto the screen? Maybe a backlight fault?

keyboard working properly....after disconnect hdmi still no display on internal screen...when it happen i try apply a torch but cant see any display or desktop icon, only have backlight

[mon2]

Is the backlight off when in hdmi mode?

[dqtech]

Is the backlight off when in hdmi mode?

no sir, backlight remain still....i try connect hdmi when internal display normal, they give both display on internal and external monitor

[dqtech]

Hi , im still looking solution for this laptop

[mon2]

Are you using the display port on the laptop?

Review the voltage to ground of the CFG4 signal.

See attached.





Also interested in the voltage to ground of +LCDVDD power rail. There is a backlight power rail and then a LCD power rail. Each is separate.

+LCDVDD is provided through a loadswitch UV24 which may be defective.