Why the screens gets dark during a phone call?

[AC Question]

Im concern because nobody in AT&T knows the phone and can not explain why the screens turns black during a phone call. If by any chance I have to press a key of the dial screens as often occurs during a service call. Do I have to return the phone and ask for guarantee of that's something normal that can be take care of? Please help !!

 

[belodion]

Welcome to AC.

That sounds like it may be a fault, perhaps with the proximity sensor.
Make sure nothing is blocking it, such as a case or the way you hold the phone. If there's nothing blocking the sensor, consider a return or exchange.
You may also care to do a Play Store search on 'Proximity Sensor', which will show several apps which may fix your problem.

Posted via the Android Central App

 

[ProfBenj]

After much research in forums and trial and error, I have traced the problem to the GLASS screen protector. This obscures the proximity sensor. Removal has cured the problem at once. Thanks to the only poster (sorry I can't remember who or where) for the suggestion. Another post led me to a useful resource, access to a range of testing utilities (including light and proximity sensors) by 'dialling' 77634#*#
Thanks, Forum, helpful as always.