Replacing Parts for Samsung DLP

I have various problems with a Samsung HL-R5067W DLP TV.  I've hopefully "narrowed" things down to the DMD board (DMD board BP96-01102A ASSY DMD BOARD W/O DLP CHIP/CHECK VER.), the "digital board" (BP94-02084A ASSY PCB MISC-DIGITAL//CHECK MODEL CODE)  and the power supply.  Does anybody know a place that has a liberal return policy in case the boards I purchase aren't the failing parts?   Given the number of different suggestions on part replacements, I would think it's not uncommon that people mistakenly try replacing parts that were not the culprits.  Samsungparts.com won't accept returns on boards unless they're defective, and Encompass Parts won't accept returns on "special items."

By the way, does anybody which board(s) has main system processor and the video decoders?

I thought they'd probably be on either the aforementioned DMD and/or digital board.

 Thanks in advance!