Strange LCD behavior on Acer E1-570 Laptop

[TheGenesis]

I have a E1-570 Laptop from Acer (Compal LA-9535P Mainboard) wich has a strange failure.

On Startup the LCD is blinking a few times (without Backlight) then goes black while still booting.
This is the Version with an onboard GTX 750M. Everything is perfectly fine on external VGA + HDMI outputs.
If I connect a external Monitor and push the Fn+LCD Button, the Monitor goes black and the same blinking is happening (as on startup) then the machine switches back to external.

Could this be the backlight circuit or the hole LCD-Panel?

On older laptops backlight and panel will still come on even if one is damaged.
There are no liquid damage or burned components on the pcb.

Anyone any idea?

[amyk]

Shine a torch on it. If you can see an image, the backlight is damaged.

[YTSOC]

 it could be as bad as a dead graphics chip(even it other outputs work), it could be a broken lvds cable

first i'd try and rule out the gpu by desoldering the coil(s) of the psu for the GPU(only the discrete one) This will deactivate it and in some cases the board automatically switches to the intel one.

[TheGenesis]

@amyk
Thats what i have tried first ... no image and no backlight.

I have desoldered the coil(s) ... nVidia is now gone  ... the Intel HD 4000 is doing the same things as before ... the approach to switch to the LCD and back to D-SUB is now faster

Are these LVDS connections are communicating with the graphic adapter? Then proabably simply the screen or, as you mentioned, the cable is gone.
I wonder, because older LCD's are flickering or doing some weird things instead of switching to an alternate display port.

[YTSOC]

weird, i think it's a basic panel, don't you have one to replace it?

i'd measure on the panel logic board the  voltages that are beying supplied from the motherboartd: 19v and 3.3v(there are 2 fuses on the panel logicboard, check the voltages before and after them)

the 3.3 v is most likely ok as the screen blackens