Help Black Screen on Phone Connect

[Bluedog8888]

So I put in the phone number and hit the screen 'button' to connect. The phone starts to dial but almost immediately the screen goes black. It continues to dial and connect so the phone continues to function even though the screen is black; however, there is no way for me to end the call or to cancel dialing.

 

[Bluedog8888]

Sorted out. I have a transparent screen protector on my phone. Some dust got under the protector at the top left corner of the screen - just where a proximity sensor is located. The sensor activates in 'call' when one holds the phone to ones head - blacking out the screen (a power saving function). Since the sensor constantly sensed the dust, the screen simply remained in power saver mode.

Did I know about the sensor? No. But fortunately the guy in the shop did.