To access the calibration menu, hold down the "Menu" key for several seconds. You will see "Welcome to digital TV." Key in 9,8,7,6 and then "Enter." You will see the 15 technical settings, along with the value of each. Write down the settings and their values before you change them, so you can return to status quo ante if you screw up. I messed around with some of the more advanced color settings "light red", "dark green", etc., and couldn't tell a bit of difference. Other settings, like "vertical height," "horizontal width," and "horizontal centering" have an immediate and obvious effect.
Enjoy playing with your Zenith Pro 851X.
Thanks for visiting my page. If you have comments or suggestions, drop me an email.