Sony z5 screen problem

[Mimozs]

I've Sony z5 Dual I bought it late December. Im facing a problem with the screen, when I'm on a phone call the screen goes dark (black) and when I finish the call and want to hang up the screen is still black or off and no matter how long or how many times I press the power button it won't light up. Sometimes the call stays going unless the other person hangs up and other times it just lights but nt before five minutes
. this doesn't happen all the time , but it's annoying. Plz plz help me out

[MarlonUk1]

have you tried solutions in these posts>?

http://talk.sonymobile.com/t5/Xperia-arc-Xperia-arc-S/screen-blank-during-after-phone-call-than-free...

http://talk.sonymobile.com/t5/Xperia-M4-Aqua/screen-blank-during-after-phone-call/m-p/1092208/highli...

[Telishia]

Hi I am having the same problem. It is extremely annoying. Didn't expect this of a premium phone that's just two weeks old

[Third]

Hi,

It seems as the Proxmity sensor is at fault - have you tried testing this in the Sony Diagnostic application. 

[z5user2]

I have the same problem.  I was told to do a software repair.  I did it and it hasn't helped.  I'm now told to send away my phone for 10 days for repair.  There's no way I can do that - the phone is my business and is in use all the time.  My phone was bought in Feb 16.  Probably a bad batch of sensors. Not good enough for an expensive handset.