Why is the screen orange on my plasma tv - Panasonic Viera TH-42PX80U Plasma TV

Sounds like display panel fault. If you wish to get some details; visit the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ Faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.

Could be mother board or screen with a plasma.

Sounds like a voltage problem to its display panel. Even a slight change in the Va&Vs voltages to the panel, all plasma displays, irrespective of its brand and screen size; will show serious and strange problems. Contact any service technician, and check these voltages. this is not a user repairable work. Va & VS voltages comes from its main power supply regulator board, and have adjustment presets are there. These voltages will be mentioned at the silk screen on the back of the display panel.
If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent.

This is a link for repairing the power supply board of a LG 42PG20, which also contains a link to an article on how to test the board's functionality, which is actually fairly simple:
http://www.coppelltvrepair.com/p/716/lg-42pg20-ua-power-supply-board-repair-service

Unfortunately it could be any of several boards, plasma sets are harder to repair because they have a lot more boards than a LED or LCD TV, its probability not worth repairing.

if you not need replaced main board you can use cable box or tv converter box

Control PCB inside the TV.

6871QCH060Q

The DVR cable box needed to be reset.

If it is new then it should be coverd by the warranty,get the tv changed as it sounds like the .ideo processing i.c. is at fault.

Try checking the cable making sure they are tightly plugged in. My dads Plasma screen started showing orange / brown colors in place of primary red... he had been moving things around and didnt realize the wires were loosened in the process. This made him realize.... GET an HDMI and get rid of all the other cables......