How is your TV connected?
If Wireless, and your new router has different SSID, password, or security settings - yes, you have to reconfigure your TV.
If you had set static IP address (wired or wireless) - yes, you have to reconfigure your TV.
How to change the settings on your TV - there is a fine manual to be read... Usually - you go to your TV' settings, from there look for Network settings, and proceed accordingly.