Whenever I start or answer a phone call, my screen goes black and will not turn on until the other person hangs up. I just recently found on my ROM that I can set the power button to end the call so I have been using that, but I cannot use the keypad to type passwords and it is very frustrating. Any ideas on what could be wrong? I am currently using the Black Edition PACRom for the s4, but the problem also happened when using the standard cyanogenmod. I am thinking that maybe the proximity sensor is screwed up but I am just very frustrated about it. Any help would be great!