Very dim projection, not the bulb.

I have an HP xb31 projector that was SUDDENLY very dim. I tried a new factory bulb, no change. The coating on the small glass lens between the bulb and color wheel is melted. It cleaned off but I suspect it is a polarizing lens that is no longer polarizing. If I shine a bright flashlight in place of the bulb and look into the output, there is a perfect rectangle that I can stare directly at. The unit and bulb have 300 hours. I have tried resetting the unit and setting the brightness to max. In a very dark room, using a proper screen, you can barely see the picture. At it’s brightest, it is just like on warmup when a projector first displays the picture, just never gets brighter than that but the bulb gets VERY bright. Being a portable projector, it may have gotten knocked around in transport so suspect something might have come loose, or that 1st lens could be causing it. I don’t suspect the DLP chip because the picture is there. I don’t suspect the light tunnel because the picture is perfectly lined up and rectangular.