Your TV has no signal if you don't have a picture and the screen is completely black.
TV with no signal/picture
Troubleshoot your TV:
Make sure the TV's power is on. Press the TV's power button. Check to see if the TV is plugged into an outlet controlled by a wall switch. If so, turn on the wall switch.
Using the TV remote, set the channel to 3 or 4.
Check your TV's connection into the outlet. Re-plug your TV cord into a wall outlet, which will verify if the issue is with your TV or set-top box.
Check to make sure your set-top box is plugged in and turned on.
Verify that other electrical equipment in your home is working. If they aren't, you might be experiencing a power outage.
My TV screen is still black.
Many FiOS TV issues can be resolved just by resetting your Set-Top Box. If that doesn't work, the problem may be with your TV itself. Review your TV's user guide or contact your TV's manufacturer. If you're sure there isn't an issue with your TV set, contact the Verizon Fiber Solutions Center.