I have a 1989 model Emerson PC6 5.5 inch FM/AM AC/DC Portable Television Purchaced in 1990. I connected a RF modulator so I could convert it to RCA so I could connect a DVD Player to it. When I try to tune in Channels 3 and 4, I get the sound from the video and a picture that looks like your stuck in between stations. What could be the problem. Please help!