I am having a problem with my Tivo that is connected to Comcast Cable. The building in which I live has a poor signal which doesn't allow the TiVo to function properly. Essentially, Comcast calls it a non-retrofitted building. I purchased a 10dB amplifier from Radio Shack without much fanfare. The TiVo doesn't change channels very easily and I get the Blue Screen of Death, the one that says it lost the basic cable signal. Any help?