Did the center conductor of the jack on the receiver get pushed out? I've had this happen to a vga connector pin and RF connector, guess it could happen on an rca plug... like the center conductor of the cable caught on the center conductor in the connector and pushed it in - then it would work as long as they were touching, but you prolly pulled it a little when hookin up new player and broke the connection.
If so, and the center conductor is now too far in to make contact, you may be able to kluge it by stuffing a little of aluminum foil in there... otherwise you gotta take it apart to see if you can get to the connector to replace it. Or have a repair shop look at it
I also had this happen to the center conductor of the rf-jack on a Panny VCR. A cable with too long a center conductor was jammed onto it... I tried to take it apart but could not get near the connector without destroying the vcr, so learned to live without the rf jack.
My exp with JVC vcr's is they are built poorly, like screws loosten and fall out (see if it rattles). Presumably their higher end stuff is better? At least a receiver has few if any moving parts...