Here are some infos of my sign:
-Its a func_brush and it contains three stages of flickering. Disabling and enabling through a relay.
-There isn't any light infront of the lightboard
-The lightboard name .vmt & .vtf doesn't have any spaces (and capital letters), and it still doesn't work.

Any ideas?

**EDIT: **
Solution:
In .vmt file, turn
$selfillum to 0
and lower minimum light level of the func_brush to 0.25

Another (probably better) idea is to put in a pti instance for the scoreboard. If you upload your map to the workshop it'll show up with correct information

Lp:
Hmm, well, that idea is good but the giant chamber number and the progress number will mess up

RectorRocks wrote:
Thanks Lp and Felix! It worked but it stills self-illuminating, but not that intense compared to the previous one. The minimum light level is 0.9. Should I tweak it abit?

Lp:
Hmm, well, that idea is good but the giant chamber number and the progress number will mess up

Try lowering the minimum level to 0.75 or lower; that'll make it less glowy.

Lpfreaky90 wrote:
Try lowering the minimum level to 0.75 or lower; that'll make it less glowy.

Thanks Lp! My lightboard looks good now.
I lowered the minimum light level to 0.25

Cheers!