A FiOS service outage can cause your TV signal to disappear, but before calling for support, check the TV setup in your house to make sure the problem isn't on your end. You might lose the TV signal from a loose connection, an incorrect input setting on your TV or due to a temporary glitch that you can solve by rebooting the FiOS hardware.
Check the Connections
A loose or unplugged cable in the FiOS TV system will cause the TV signal to degrade or vanish. In addition to the power cords on your TV and the FiOS set-top box, the set-top box connects to a port in your wall with a coaxial cable. Standard definition set-top boxes use a second coaxial cable to connect to your TV. If you have an HD set-top box, it can connect with either an HDMI cable or component cables, which consist of 5 separate cords. In addition to these connections, make sure your FiOS router is connected and turned on. FiOS TV requires a working router even when you aren't using the Internet.
Check the Input
After checking all the connections, make sure you have your TV set to the correct input, based on the type of connection you're using. For HDMI or component cables, set the TV to the corresponding input. If you use a coaxial connection to your TV, set the TV to the "TV," "Cable" or other similar input and tune to channel three or four.
Reset the Hardware
If you continue to have trouble with an HDMI connection, resynchronize the connection by turning off both your TV and set-top box, and then turning the box on first. For other types of connections, or if a regular reboot doesn't help with an HDMI setup, unplug both your set-top box and FiOS router for 15 seconds to reset the system.