MY TH-58PZ800U is giving me a pictures with dark red shadow

Hello Gilbert,
The plastic ribbon cable can be fixed by cutting a very very small amount off the end of it to remove the damaged connection with a very sharp pair of scissors but not too much! Be real careful when you attempt to re-install it!
Whether or not it is the C1 board can be answered by looking next to the 2 black connectors and the board model is located inside a square box. You can order a new one here; Panasonic TH 58PZ800U TV Parts
The number given (821ar053) is not a valid part number for the board (maybe it's for an IC?)
One of the below suggestions under "related questions should help with the line issue.
Good Luck!
Rich Lilja

go on youtube or goto your manual ,

Adjust the aspect ratio to picture. Refer its user manual for details.
http://electronicshelponline.blogspot.com/

15V SOS section should be troubleshooted. If you wish to get more details about these blinking codes to Panasonic Plasma displays, check this link.

Visit the site named 'Electro-help' for more details. Click this link. View it in 'Flip card' option, which can be selected from the drop down box menu by the [Sidebar] tag, at the top left corner of the display window. It will make search easy. Some times, the ads attached with each posts, both at the right and bottom, might help you to find the availability of spare parts. There are more than 880 posts to different brand TVs now.

Count the number of blinks occur at one time very carefully. There is no chance for a 10 blink pattern for this TV.

Visit the site named 'Electro-help' for more details. Click this link. View it in 'Flip card' option, which can be selected from the drop down box menu by the [Sidebar] tag, at the top left corner of the display window. It will make search easy. Some times, the ads attached with each posts, both at the right and bottom, might help you to find the availability of spare parts. There are more than 880 posts to different brand TVs now.
pull up older posts there.

my panasonic th-58pz800u well not even come on no blinking lights at all

TV shows large red spot in middle of tv when dark show are on, you can see it more.  Now blue spots on upper right side too.  Spend way to much on this tv to have these kinds of problems only after 3 yrs.

use the advanced options page and reset the factor blue and red convergence defaults then do re apply the auto color defaults color at first it seemed very red (which is good because red was the missing factor in the green picture) but after reseting all the color and tints to the normal ranges I then reset the color auto correct again and all seems fine.