Certain models of Samsung LCD TVs have problems caused by defective capacitors which expand and swell.
My three year old 40 inch Model LN-T4065 set would show pink/purple spots when it was first turned on. Turning it off, waiting awhile and turning it back on usualy fixed the problem - until the next time
Other people have had it progress to the point where it takes minutes for the picture to appear or not appear at all!
I found a forum where 23 pages of threads discuss the problem and solution. I replaced four 1000 uf capacitors and the problem is resolved.
The origianal ones were 10v and the new ones are 35v - a little bigger in diameter but just fit.
Also, I used 85 degree centigrade rated caps since they were available at Radio Shack, but the original ones were rated 105 degrees. I intend to buy some 105's just in case.
The forum discussion is found at: TechReport.com