Has anyone pointed out to you yet that this model uses the LED illumination system and so HAS NO LAMP AND NO COLOR WHEEL? Now it is very possible that one of the LED Phatlights has gone bad, and my guess is it's the RED LED. If all your LED's pass the test here, then suspect your ballast. Here's a quick and easy way to test the LED's in your set. Open up the back, remove the light engine, or at least pull it as far out as possible.
Remove the plastic ducting on the right side. You'll see fat wire leads going to each of the three Phatlight LED's (one green, one blue, one red). Take a 9 volt battery (the usual drugstore variety) and after pulling off the wire lead to the LED, touch the two terminals of the battery to the two terminals of the LED. Did the LED light up? Look into the large glass lens to your left to see if you can detect a red light. REVERSE the battery connections if necessary. This sounds scary but LED's only work with electricity flowing in one direction and you can't hurt them by doing this. Did it light this time? If it lights up, it's okay. If it does not light up, it's a dead LED and will need to be replaced. Be sure to use "heat sink paste" when you install the new one. Cleaning everything in that portion of your set is also vital, especially between the copper fins that act to disperse heat. It may sound daunting, but anyone with a good screwdriver can do it. Take pictures so you know what goes back where. Hope this helps.