Look for a headphone output jack. If this model has one, (possibly on the back) then you can use the headphone
jack for an audio output. Get a cable with mini-headphone stereo out plug on one end to two RCA plugs at the other end.
Connect to your JVC aux input or tape input. (not phono input)
Adjust JVC stereo volume with a different source, such as tuner or CD, then switch to the input with the tv headphone cable and turn
up the volume on the tv to match the volume from the other JVC source.