Im having the same issues with my samsung 61in DLP. Bulb replaced, ballast is fine,no sounds from color wheel, but I did find two disk type Thermistors #KL15L 5R1(next to the relay on the main power supply board upper right hand side,that had gotten very hot and discolored the board on the back side) I have since learned that they are voltage limiting devices that are there for surge protection. They are right near a contactor believed to be going to the ballast pwr supply.This is where I have run into a dead end on finding replacement thermistors. I can not find a cross-reference for sutable replacement thermistors to solder in. Any ifo would be helpfull, also If anybody has any new answers to the intermittant shut down problem they would be greatly appreciated