I have just installed digital cable, using a Motorola cable box. I routed the coaxial cable through the vcr, so I can record shows if I want to. Now, I can't watch shows when the VCR is set to video. I have to set it to TV (essentially turning the VCR off). When I try to record, all that I get is a blue screen recorded on the tape. I have been able to do this before with digital cable.
Split the incominng cable to the box and VCR, then connect RCA cables from the box to the VCR and VCR to TV. When you want to record analog channels, use the VCR tuner, when you want to record digital channels, use the box and set the VCR to line.