Black screen during calls, problem on Windows Phone ?

A few people have encountered persistent problems with their screen going black whenever they make or receive a call on their Windows Phone 8 device. Its very irritate. This makes it

unresponsive, so it’s difficult to cancel or end the call. It seems to be a problem for the Lumia 920 specifically.

Workaround:

• If you tap the power button twice the screen should blink back to life, but you may have to act quickly to end the call.

Potential fixes:

• This is likely to be an issue with the proximity sensor. Make sure that you don’t have a screen protector covering it. It’s located next to the front-facing camera at the top of the front face of the phone.
• You should also make sure there’s no dirt covering it. Give it a wipe or try using compressed air on the top edge to blast any dust away.
• Some people have reported success by pushing on the screen where the proximity sensor is located, which suggests a build issue.
• You could ask for a replacement unit, although some people have encountered the same issue on more than one device.
• Enjoy.....