why does my plasma tv screen occasionally blank


I have a Samsung PN42A450 connected via hdmi to pioneer elite vsx 92 txh receiver. my time warner hd cable box is also connected to the receiver via hdmi.
My problem is every few weeks on some occasions the tv screen goes completly blank and black for a second or two without any sound and then comes back to normal. this keeps repeating sometimes every few minutes.Please advice
thank you.
laptopdoc
I have an Elite Pro 151fd and this happens to mine to but I have noticed it has only been while watching MNF in Hi Def
sorry i actually noticed that the sound is there only my screen goes black..so i tested by putting a dvd in the dvd player also connected via hdmi to my receiver and it plays fine..so i am guessing its the cable box. i will change it and see.