Samsung j7 Blank Screen but not Physically Damage

So, I have Samsung J701f core I didn`t do anything when it becomes blank, i just turn it off and on nothing happens then I search in internet how to fix it by pressing volume - and power button, at fifth time, my phone turn its screen on and The LCD has no damage and working fine so, I’m relieve that the LCD is not the problem, also the touchscreen is working fine. then the screen turns off because of time out. Then when i press the button again the LCD wont turn on AGAIN. so I repeat the instruction with the volume down and power button trick but no luck I’ve been doing this for 2 hours, I Already flash a new rom in my phone, by the way, the download screen didn’t show also the recovery. so i’m wondering what is the problem and how do i fix it? anyone i already tried the all the internets recommendation except for hardware repair by my selfPS: I dont have budget to go to repair shops, and or buying a new phone.