How can I fix my Magnavox VCR, HQ? Number 050 or OSO?

When I tape a show, it occasionally starts making lines across the picture. The lines start at the top and go down to the bottom. It isn't doing it all the time but I cannot do an hour taping without lines during part of the taping. I have put the tape cleaner in it several times, but it hasn't cleared up the taping. I can play tapes clearly that I recorded quite a few months ago. So it doesn't seem to be the playback that is the problem. It is happening when I try to record a program now. The play-back always has lines at some point. There doesn't seem to be a pattern as to how long it records before messing up with lines. I assume there must be a glitch in the tape while recording to cause the lines. It affects the sound of the program and I can hear a popping sound when the lines appear.