s4 black screen problem.......... again!

[AC Question]

so i watched a video on youtube to fix it i opened the phone and heated the motherboard with a heat gun and it worked but when i opened play store and tried downloading things it stopped working and the black screen came again, i'm afraid if i do the same the same thing will happen and the black screen will be back. HELP

 

[B. Diddy]

We can't really look at any other post you may have made, so we don't know about your prior history. Why did you use a heating gun?