Because I like this zenith 27 inch TV large black TV

SOURCE: Zeith 27 inches 2001

You will need a Zenith remote with a menu button
There should be a "hidden" menu. Before you access it, I want to warn you, do NOT change any values of anything you don't understand what it is or does. You can PERMANENTLY DAMAGE YOUR TV. Also, write down the original values of anything you change before changing it!!!!!
If you still want to proceed(at your own risk), here ya go.
1. Press and hold the menu button until
the menu comes up on screen and then
times out (5 - 10 seconds)
2. Immediately press 9, 8, 7, 6, Enter.
3. The set should now be in the service menu
mode. To access most of the features
selection 00 needs to be toggled from 0 to 1
4. After your adjustments 00 needs to be
toggled from 1 to 0
5.Feature 16 unlocks the auto-program (change to 0)

SOURCE: No Original Remote , Which substitute

Hi,
Required remote for your TV is available HERE.

SOURCE: Zenith tv picture jumps after 20-30 min.

the variations of the supply causes that. a verticle stability be checked, specially semiconductors and capacitor changing valuas
Q= CV
Q=IT
THEREFORE

IT=CV=Q AND frequincy = f=i/t
so if I AND T CHANGES CAUSING MOVEMENT OF PICTURE

SO I is for time and T for tempareture

SOURCE: 27 inch Zenith TV Vertical too big

If you are using a DTV coverter box, you may have changed the aspect ratio with your remote control. look for a button marked "aspect" or "picture size" use that to change size.
If you have a cable box, you may have a similar button.
Or you may find a picture size adjustment on your TV remote.
If you do not have "aspect" button on your remote try going to set up menu and look for picture size.
Older TVs used to have a vertical size adjustment at the back. look in the manual.
If none of the above, you have a biiger problem with the TV internal parts needing attention

SOURCE: need remote codes for Zenith B27A11Z 27

001,004,089,099,105,177,197,200,....hope this helps....