HP Pavilion Gaming 15 "Delete" button backlight is not working. (Solution in the Description)

[Khandan]

Hello guys. I'm a helpdesk engineer in a telecommunication company.

A colleague brought her laptop -which has been bought very recently- to me with the same issue (She has a purple one).
Since I'm a hardware support and I know how keyboard backlight works, I only suspected the keyboard production defect.

Normal Keyboard backlights (Mostly single color ones) have a transparent glossy plate underneath the keyboard which is lit by a few LEDs. The light emitted by the LEDs is reflected through the glass screen under the buttons.
Thus based on this structure, If a single button is not lighten up, It's either the button or the glossy plate which is damaged so the light can't find it's way out through the button.

In this case when I removed the button (you can pull the upper side of the button and carefully remove it) I saw a fabric-like layer is covering the area under the "Delete" button.

Since the button was OK (The Characters of the buttons are transparent so the light could pass through), I'm almost sure this was a production mistake (Or I couldn't find any reasonable cause for it).

So I carefully removed that layer and voilà!!!

[Khandan · Accepted solution]

I've posted this for those who have faced this issue on the following thread:
https://h30434.www3.hp.com/t5/user/v2/viewprofilepage/user-id/4326493