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View Full Version : G751J black screen issue, what powers the back light?



Jyuma
03-24-2018, 12:08 PM
This is my first time working on a G751J laptop and I need a little advice.
Spilled a glass of soda on the laptop while it was on and as you might expect... it didn't turn out well.
The keyboard... shot.
The WiFi network card... shot.
The battery... well, probably already toast at the time but after... shot.

Immediately after the big spill, amazingly the laptop still functioned but only on external monitor. The laptop screen was dark but I could see very faintly that the video was there but no back light.
Replaced the keyboard, WiFi network card and battery but now I'm left with a laptop screen that needs some light. My trouble is that I can't find any information on what powers the back light. I took the screen apart but can't find an inverter... only the driver board for the touch screen. Perhaps it serves double duty? If not then the power for the back light must be on the mobo but again, I can't find any information on it.

So after that long winded explanation... can any one point me in the right direction? Is there an inverter? If so, where is it? If not, what on the mobo supplies the power for the back light?

Thanks

Jyuma
03-25-2018, 12:01 PM
Come on guys... nobody knows where the supply voltage for the G751J back light comes from?

Jyuma
03-27-2018, 06:42 PM
Really? Not a single person has any idea where the power comes from to illuminate the back light on a G751JM?

Jyuma
03-29-2018, 03:11 PM
Is there someplace else where I should be asking a support question on a ROG G751JM gaming notebook or is the ROG/Notebook/G Series Gaming Notebooks message board the wrong place to ask a support question on a ROG G751JM gaming notebook? Just curious. :)

cl-Albert
03-29-2018, 09:34 PM
Is there someplace else where I should be asking a support question on a ROG G751JM gaming notebook or is the ROG/Notebook/G Series Gaming Notebooks message board the wrong place to ask a support question on a ROG G751JM gaming notebook? Just curious. :)

Hi,

Not sure how accurate it is, but check the third-party page below which I believe may help understand what is going on and consider searching online for more information if you wish or think it's necessary.
https://www.laptopscreen.com/blog/tag/does-my-screen-come-with-an-inverter/
(https://www.laptopscreen.com/blog/tag/does-my-screen-come-with-an-inverter/)
Basically, the newer 'LED' LCD screens don't use inverters like in the 'old days', so probably something fewer and fewer people will know about as time goes on.

Hope this helps .

Jyuma
03-31-2018, 04:01 PM
Hi,

Not sure how accurate it is, but check the third-party page below which I believe may help understand what is going on and consider searching online for more information if you wish or think it's necessary.
https://www.laptopscreen.com/blog/tag/does-my-screen-come-with-an-inverter/
(https://www.laptopscreen.com/blog/tag/does-my-screen-come-with-an-inverter/)
Basically, the newer 'LED' LCD screens don't use inverters like in the 'old days', so probably something fewer and fewer people will know about as time goes on.

Hope this helps .

Thank you for your reply.
Unfortunately I have already searched the Internet for info on the back light supply voltage on the G751JM but the closest I could find was a video showing what is most likely a surface mounted coil that burned up when the person shorted some wires. I believe it was causing his back light problem but I don't think it was the same model as mine. I was hoping someone here already knew the location of the component or components that supply the back light voltage for my screen but apparently that is not the case. I'll keep looking but I might just have to use the laptop with an external screen. It's not like the thing is portable anyway... it weighs a ton.
Thanks