I am not sure what you have but unless the set has been
modified you need a modulator. That will take the 3 RCA jacks & convert it
to run on channel 3 or 4. You can run a DVD also with it.
Second issue is compatability. The only add on at the time was a UHF converter. Newer add ons often have sync problems. And if you are
coming in on the antenna try the AGC control & see if it helps. It
may be to high.
73 Zeno
LFOD !