Make sure the RF Channel switch on the back of your NES console is set to the same channel (either 3 or 4) as your TV.
Also works for SNES or SEGA Genesis 1.
For improved quality check out our original pre-owned Nintendo brand RF switch for SNES or NES, or our ,NES/SNES/SEGA1 Exact Replica RF Switch
, both of which have screw-on instead of plug-on coax connectors giving better quality, or our NES AV cable.
If you want to connect to the red-white-yellow plugs on your TV, you need an AV cable instead of an RF switch.