Black screen with sound = burnt backlight LEDs in most cases. Easy test: shine a phone flashlight on the screen while playing a channel — if you see a faint image, that confirms it. Fix by replacing LED strips.
See if any of these signs match your device — each one increases the likelihood of this fault.
These are the causes we encounter while repairing Black screen with sound — ranked from most to least common.
Burnt backlight LEDs (most common, 80%)
Power supply not delivering 12V to backlight
Bad backlight driver IC on T-Con or main board
Disconnected backlight connector internally
Burnt backlight fuse on power supply
Any of the following = a danger signal — call now and don't try to fix it yourself.
On-site diagnosis, clear pricing before any work, and a documented 6-month warranty.