New dynex 24 in tv-working good but only shows 19 in picture. How to stretch to full screen?

You did not list your brand of TV, so this may not be applicable in your case: on a Samsung Smart TV, use the remote to open the "tools" menu; the picture size and other picture options will appear on the upper right screen. However, please note that some cable/satellite channels do not fill up large screen TVs no matter what tools or settings are available. The "Chiller" channel on my set always has a border; all the other channels fit the screen accordingly.

Comcast remotes generally do not allow you to use the menu option for your TV. Check the Dynex website by entering your model number to find the manual for your tv.

Chances are somehow the screen setting options were changed. Go into the menu and try the different screen formats. Usyaully there are stretch and zoom settings. When viewing a non-HD station you will typically see black bars on the sides of the screen set the option to your preference.

Nope. The picture resolution has to be 1080 to fill the screen completely. Using stretch and zoom will distort the low rez pictures. No option to change resolution on the TV itself.

check the ribbon cable that connects the screen to the mainboard may have a loose connection

Be sure to remove the dvd from the drive when you want to watch tv.

Make sure the cables are pushed on all the way. I've had a similar problem.

The reason for this is that the incoming signal is not always the same. Stations broadcast in different formats from 480i to 1080. If the bars top and bottom or side to side bother you then you'll have to stretch the picture (try different modes) to keep the picture screen full.

The LCD panel is defective...sorry I have to give you bad news.

My 42" Dynex just did the same thing. 65535 NO SIGNAL.
The channel label for this said "ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ"

I went to menu... Channels .... Set for Cable TV... Scan Channels.
It rescanned. It took twice as long as normal to scan.
After the scan completed it worked fine except of one thing.

ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ stuck on the screen.

I shut the TV off, then things returned to normal.

Hope this helps.

Notes:
This TV is only 6 weeks old.
Cable hook up.
It is -plugged into a brand new UPS power supply.
I used the sleep timer to shut off TV. The 65535 problem occured the next time the TV was powered up.