Just ordered/upgraded from an ordinary SD to a HD stb and got everything working. the only problem i have is when i go from an SD channel to an HD channel (ex: ch50- 550) there is like a 15 second pause where the screen goes black and my t.v. says "signal searching" but then it works again. Note this only happens when i go from SD to HD or HD to SD not from the same. Whats wrong?