PIP Problems

Just yesterday I finally received my Hitachi 42" plasma TV. I am very pleased with the product--with one exception.


I am feeding the cable signal (Comcast cable) to the Motorola CATV box, then from there to the TV via a DVI-D cable. This input is "INPUT 1."


Using a splitter in the cable line BEFORE the CATV box, I am also running a short coax cable jumper to the TV "CABLE IN" connection. I understand that I won't receive the digital channels that must be decoded by the CATV box on this input, just the analog channels.


When I attempt to use the PIP function, INPUT 1 displays, but the other box is black. When I try to select the black box, I see the message "No channel detected," or something to that effect.


If I am reading the Hitachi manual correctly, I *should* be able to view INPUT 1 (DVI from the cable box) on one PIP screen and the analog CABLE signals on the other. Or have I misunderstood?


Thanks . . . Steve