I have a large 50" plasma Samsung TV originally bought in 2006. It either has a non-functioning power supply, or other internal problem. Do you accept donations of non-functioning TVs such as this? and arrange pickup?

They will not take it as a donation. They will either break it apart or 1 of the workers will take it home.

They accept TVs and charge based on the weight - $0.35/lb if you drop it off at their facility.

Try www.ifixit.com free online forum & repair guides to fix all kinds of things, especially electronics technology.