I was google-ing and came across this thread because I has the same problem with my pixi. Every time I make/receive a call my touch screen would go blank. It made me think there were problems with my pixi. I got the phone about 3 weeks ago. Until I have my screen protector, I was hesitant to take off the film screen protector that came with the phone. The top part was peeling and it had dust on the film. I was trying to figure out how it keeps going blanks on calls and when it went blank again... I lift off the protector from the sensor (IR look-a-like-thinging) left of the phone speaker. My screen came back on again.
So make sure the sensor is clear of dust or other stuff that may block light.That's the one! Thanks. It's interesting to see how many other people there are out there who left the screen protector on. My wife makes fun of me over it.
I guess it's time to peel that bad boy off now though.
