I bought my Pioner VSX-521-K in May 2011. When playing from the cable box/PVR, it has periodic video blackouts lasting 2-3 seconds. The blackouts happen at random intervals of 5-15 minutes. The sound continues to play with a black tv screen, and the picture eventually returns. This only happens when playing from the cable box, and does not happen while playing a DVD. Is anyone else having this problem? The blackouts can start almost immediately after powering on,...