Today's weirdness: My 721 lost its RF output. (I use the RF out to feed the BR, Office, and Den.) Of course, it's the last place I look, thinking someone must have monkeyed with the splitter in the Utility Room, or maybe the RF amp went bad. Finally, I decide to connect the 721's RF output directly to the RF input on the HDTV. At this point, I see the boot up diagnostic screen. It rebooted by itself! Now, the RF output is working OK again. Has anybody else lost RF output, even though the S/V/L/R outputs were working OK. Then, after a while, it just spontaneously reboots?