Samsung 56" Rear Projection.... NEED HELP ASAP

I am about to purchase a tv off of craigslist but i need answers first, the add is for a 56" Rear Projection 1080i, model # hlp5685w, the add states that from time to time, but not always the tv starts to show red pixels (projection has pixels?), and claims that after research he believes its the convergence board. pictures of the tv during these issues it appears as though theres red paint or melting affect on the screen...... would this problem sound like a convergence board and if he will except an offer of 150 should i take this risk? please answer fast if you could i need to act fast on this