So you got it working with the
HDMI cable?
It sounds like the problem before was the setting on the TV. You didn't have the right input selected.
If you use coax between the
DVR and TV then put the TV on TV input either ch 3 or try ch4
If you use rca cables between them try putting the TV on one of the Video inputs.
If you got pictures but no sound, then the picture rca was plugged into one input and the sound cables in another.
and yes, using RCA cables your TV should take the output of your DVD/
DVR/VCR boxes.