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G751JT Black screen issue.

Level 7
First of all this is my first post in this forum so hello everybody , nice to meet you ! 🙂

I have a G751JT with a tricky problem. I had the battery died for about a year now , and decided its time to replace. So I ordered a replacement watched some tutorials on the internet and changed the battery at home. After the first boot I had some problems with Windows , said alright , lets just reinstall the System. Reinstalled Windows 10 , got the machine back to work again , everything Works fine , the battery holds the charge well etc etc. So I got to the point of installing the drivers as it was a fresh install . This is where things get tricky.
As soon as I install any version of the GPU (gtx970m)'s driver the screen goes black ( does light up, it is just black ) and refuses to display the image . However , connecting a secondary screen via cable Works well. It does display to the secondary screen without any issues , Iam being able to use the GPU under load , play games , benchmark etc. The device Manager does not show any malfunctioning. The notebooks main screen Works up to the point of Windows being booted up , so the rog logo is displayed , Windows loading is displayed then once it is all booted up the screen just lights up black and thats it until I connect a secondary one or delete the driver of the GPU.

Things I have tried so far : reinstalling older and newest version of win10 (updates)
installing win 7
putting back the old battery
holding the on/off button for 1 minute 3 times repeated
pressing the display on/off button on the notebook's keyboard
using Windows 10's dual display System ( the one that allows you to choose which screen would you like to use , main only , secondary only , use them together as an extend etc )
installing newest bios 211

The notebook is at RMA (in Hungary ) right now but they cant seem to figure it out either , been there for a month now .
Any help is really appreciated and sorry for my long post and poor English

TLDR: G751 battery replaced at home
Windows didnt boot propely had to reinstall
Now the GPU seems to go nuts and does not display the image to the main screen only to a screen connected via cable

Level 7
So basically the screen doesn't seem to accept anything other than low res VGA (or whatever it uses during BIOS/logo/Windows startup)?
Can it be run in safe mode, or doesn't that exist anymore with Win 10 :confused:

The screen was replaced on my laptop and it seems these are fairly cheap, can be found for 70-80€ on eBay.
Worth a try testing with another screen? Have they checked all screen cables etc?

Sounds to me like either a screen cable got knackered during the opening of the case/replacement of the battery, or the screen itself died somehow.
If the GPU were at fault, it wouldn't work with an external screen either...

Level 7
Well it does work in 1080p still without the drivers being installed.
I have the same opinion that the GPU *cant be faulty since it is working perfectly if an other display is being connected.
However RMA says that they think the GPU is the fault for the issue since “it doesnt matter if it works on a connected screen because that is being controlled from a different port “ thats what they said.
I havent tried to take apart the screen yet but I will ask RMA to do so and check for any cable or issues inside the screen. Maybe they can even try it with an other screen if they have it in store.
Anyway , thanks a lot for Your input it is very much appreciated :)*

Level 7
Hrm I'm not an expert but in the end, regardless of port it's using, it's the same GPU doing the maths and all... I'd ask them to try another screen if they have one.
Looks like these can be had for around £50 on eBay:

This one even cheaper:

Actually I'd check the cables first. On my G701 there are several cables routed behind the screen bezel (not sure what it's called... it's the part sitten behind the screen and that has to be removed when opening up the laptop.) I can see how it would be possible to damage something there when opening up the case. On the other hand, it may be more likely that you'd have a completely dead screen in that case....

I found this in another thread, completely different laptop but same symptoms:

Charger760 said:
Hello, my laptop screen won't display anything. It boots up and displays perfectly through an hdmi and my T.V.. I can't adjust my screen brightness either, nothing comes up when I use the brightness function keys, the other function keys work fine. I went to device manager and everything under Monitor and Human Interface are updated. Under Monitor the device is Generic PnP. I'm on an Asus laptop, Windows 8, 64 bit. I'd appreciate any advice.

Typically if it works on an external source it's not the graphics card and it's the internal screen, screen components or cable. I had that happened and it turned out to be the LCD cable.

Here's the source:

This does sound more like screen not working at all though...