What kind of rear projection?
If it is a non-HD CRT rear projection, just place it to the curb - isn't worth fixing. Same goes for if it is a smaller screen size HD CRT rar projection.
If it is a large CRT, might be worth a DIY try from googling some options, if it costs under $100 to repair. Otherwise, curb it.
DLP, LCD, and LCoS, etc. rear projections I would look online first (a number of LCD rear projections have light engine issues), then I would suggest contacting Mercury Keller. The place is in a shit hole part of town, but they do good work.