I have a vertical strip of black down the center of my Panasonic TH 50PZ800U television. What is the source of the problem? Can I fix it?

It could just be a bad connection on the driver board or worst case it could have failed.

First you need to disconnect from the mains and leave for 5 or 10 minutes to discharge.

If you remove the rear of the screen you'll see the driver boards as items 7 & 8 at the folowing link.

http://www.mediafire.com/imageview.php?quickkey=nzujidjtm1j

Disconnect the ribbon cable from the board thats below your black line and put some tape around the end of it to make it safe.

Now turn the power back on to check that it's the correct board in relation to your black line.

If it is then turn the power back off and leave for 5 to 10 minutes again.

Now check that the ribbon cable and control board show no signs of corrosion or damage.

If they both look OK then reconnect the ribbon cable making sure its fitted correctly.

If when you turn on again you've still got the black line then you've 2 options.

1) Remove the board and check for dry joints and resolder where necessary.
2) Replace the board.

Let me know how you get on and I'll look for replacement board costs and availability.