what component controls screen visibilty

[AC Question]

my screen is blank what controls that on the circuit board

 

[anon(632115)]

You need to take that device to a repair shop, it's impossible to assist with a hardware issue

 

[Rukbat]

The "Device" that controls it is the GPU, which is on the motherboard. The GPU doesn't get replaced, the entire motherboard does. Assuming it's a component - the cable from the motherboard to the screen could be disconnected - that just requires being plugged back in. (Don't do it yourself. And don't be surprised that it costs so much - taking the entire phone apart and putting it back together is the expensive part - replacing the motherboard or plugging in a cable are easy.)