How come my backlight is not working?

@techb31 this "there is still no backlight on the original display." would mean that you have a bad backlight in the panel. Of course, you made sure that the display and the computer that you tested it on, are compatible. It is not enough to assume that just because they have the same connector, that the wiring is identical. Have you checked to see if your can see your desktop etc. if you shine a flashlight beam at an angle against your display? Try that in a darkened room and see what you get.

I suggest that you post some good pictures of your motherboard with your Question. then a separate one of the display connector. Let's see what it looks like. It is possible that this is a connector issue, a backlight power issue (blown fuse etc.) or a bad backlight driver issue.

Hi @techb31

If the motherboard model number is Asus X510UA V3.0 (apparently this board is used for F510UA as well) then if the replacement LCD panels are compatible, here are some images showing the backlight power circuit and backlight enable/disable circuit for the model.

I'm not that familiar with the way this circuit is drawn out and I don't know what component designation SL means but looking at the way it is drawn I think that component SL4505 may be a fuse with a package size of 0805, but as to its rating I have no idea.

Anyway check if there's a voltage on the eDP connector pins 37→40.

If not try to locate the component SL4505 and check if there is a voltage on both sides of the component or with the laptop turned off, if it measures 0.00 Ohms i.e. a short circuit, which it should

Normally there is voltage supplied all the time to the backlights and it is turned on and off in the panel by a voltage signal (3V-5V) on the backlight enable lead (pin 34 of eDP connector) so maybe check if the diodes (D4501) are OK or not.

I found this link for a boardview of the motherboard, to show where all the components are located, but did not open it etc and I cannot verify the supplier or what info is needed to be supplied by you to download it. You may have your own sources and if not its your decision to use it or not.

(click on images)

Note: ignore the circles shown on the schematic in the 1st image. They were already there and not done by me. I added the arrows and the rectangles ;-)