SONY RDR-GX300 drive replacement

I am a huge fan of the SONY RDR-GX300 DVD recorders. I’ve been wondering if anyone out there has had success in replacing the drive in one. I have been using them for several years to build up a movie library. Although they do have the copyguard circuit to prohibit copying from an original DVD or Video tape, they don’t have the circuit that prohibits recording from the premium movie channels like newer DVD recorders do. I started with the one I bought new when they first came out and have purchased several others from EBAY over the past few years as my original began to show its age. I suspect the unit is either designed to accept only the original SONY model drive that was used in manufacturing or at least a particular type of Sony drive. The drive used by Sony is motor driven without any belts. I have dismantled one that has failed and cleaned it well but it continues to fail. I tried an ASUS CD/DVD combo drive but it didn’t work.