How can I fix my "wavy line" NES video problems?

[ApolloBoy]

Have you checked the big power filter cap inside the system?

[Ziggy]

Try using your NES on a different TV in the house, preferably in a different room, and see if it has the same problems.

[CRTGAMER]

Have you checked the big power filter cap inside the system?

THIS. Maybe its starting to go, the capacitor is mounted in the RF Modulator. In my NES there was no warning, just an instant fail with a black screen and rolling horizontal bar.

[ApolloBoy]

Have you checked the big power filter cap inside the system?

THIS. Maybe its starting to go, the capacitor is mounted in the RF Modulator. In my NES there was no warning, just an instant fail with a black screen and rolling horizontal bar.

If that filter cap starts to fail, it could potentially introduce ripple which could cause the problems the OP is having.

[Zing]

Toasters are so cheap that you could easily buy another. Keep this one for the pin connector if needed. I'd stay away from the toploader, as the jailbars will be almost as bad as those lines.