Ask them if they have one for this model. In your case since it was not purchased there is no question about the warranty. So here's the video. It's a little over 100 for the chip but I don't sell them so my number can be way off for reasons such as the Japan nuclear disaster (the chip factory was over there).
Here the video -> http://www.shopjimmy.com/blog/2012/07/18/dlp-tv-repair-the-dreaded-whiteblack-dots/
I am new to these forums but I hope to find the solution to my problem here. I have a Samsung HL-T5075S DLP TV that I found outside my apartment by the trash can (someone did not want it anymore). I figured I would take it and see if it works. At first, I noticed the lamp was burnt out. I ordered a new one, and installed it a couple of days later. The TV turned on and I saw multiple small white dots all over the upper part of the screen. I researched about this online and found that I may need a new DMD board or a color wheel. I am not really sure what is wrong, but I'm hoping to find help here. Many people will probably try to refer me to Samsung, but the problem is I never purchased the TV. (BUT I do have the model # and the serial # on the back!). I'm not really sure what to do, but I don't want to spend money to fix this. I heard Samsung is fixing this issue for free, but am not entirely sure how that works. If anyone can help, it would be greatly appreciated! Thank you!