Zenith Advanced System 3 Red Lines

[homeboyflux]

I picked up an old Zenith CRT today and plugged it in and everything seems good except on black screens horizontal red lines appear. It's not noticeable most of the time but I was wondering if anyone knows a possible fix or a solution because I love this TV. The setup I have is a Genesis plugged RGB into a RF modulator into the coax antenna plug. Is that the cause of the issue? Thanks for the help, here's a photo to help explain what's going on.
https/ibb.co/dAKmi5

 

[homeboyflux]

First image link didn't work, here's a mirror

http/imgur.com/6pYtadW