I have a five year old Vizio P50HDTV20. While watching it the other day the center 1/3 of the screen went black from top to bottom. The left third and right third are fine. This condition persists with all input devices. Any idea what part might be the culprit?

There is a good chance your panel is defective and the set not repairable but before you condemn it I'd try a t-con board, in most cases they aren't real expensive.

You need a factory service center

CHANGING THE SCREEN ASPECT RATIO: ( From Manual )
The TV can display images in four different modes: Wide, Zoom, Panoramic, and Normal. Each mode displays the picture differently. To change the screen aspect ratio:
1. Press the MENU button on the remote.
2. Use the Arrow buttons to highlight the Wide icon. Press OK.
3. Use the Arrow buttons to highlight your desired screen mode and press OK:
• Normal preserves the content's original aspect ratio. Since the 4:3 aspect ratio is not large enough to fill the TV's screen, black bars are added to the left and right of the display image.
• Wide stretches a 4:3 aspect ratio picture to the edges of the screen. Since the picture is being stretched, the display image may appear distorted. If the program is already formatted for widescreen viewing (1.85:1 or 2.35:1), then black bars will appear on the top and bottom of the display image.
• Zoom expands images with black bars to fit the screen.
• Panoramic expands the display image to fill the screen.
images may appear wider than intended.
If you are watching widescreen (1.85:1 or 2.35:1) content, black bars will still appear on the top and bottom of the display image. This option is only available when the TV is displaying a 480i/480p source.

Id start by replacing the tcon board, its the small board generally at the top of the set. sometimes under a metal cover

If it is still under warranty, take it back ASAP. The panel could be failing, TAKE IT BACK

iam also facing same problum,that problum wont start immedietly,when we r watching after 1 hr it will start

Cannot offer solution but my mine has also gone bad.  At first a black shadow appeared on the left side of the screen.  Took it to the authorized service center.  they kept it a few days, said nothing could be done.  Used it anyway for the next 5 years when suddenly it went black (or sometimes blue) after working perfectly for the first 5 minutes. A sharp rap next to the right speaker fixed it a few times, but no more.  Good luck. 

Bill

[email protected]

If it's the same watch I have, the four dials from right to left are day of week, hours left in the day, date 1-31, and possibly a chronograph (mine makes 2 revolutions/minute). On the case, there are three large knobs on the right and two small flush screw-like objects on left. The large knobs (top to bottom) are month selection, time set, and day of week select. Month and day can be selected by pushing the knob to the desired date. On the left, you will need a fine pen or stylus to press the center. Top to bottom, these two buttons control year and date selection.

I had the same issue happen to my vizio lcd just this weekend. Everyone is telling me is a bulb or backlight or something. It would explain the loud pop and no picture, but I'm not getting sound either so I'm not sure what exactly happened. Only after about 2 years too. I'm trying to find parts to just fix it myself.

Vertical section problem

change all caps in vertical sec and replace vertical IC