Beware of some of the ebay replacement parts. I've replaced the laser drive in my Cary 303/300 three times now over 15 yrs or so. Instead of buying the part from Cary I tried an ebay seller and the part was DOA. Tried the same laser drive out of a used DVD player and it didn't fit just right even though it worked and was a noisy POS. You'll like this - Cary wouldn't warranty the part if I did it myself claiming folks ruined them trying to do the install. Good luck...is this Will the renoun ST70 builder? Should be a piece of cake for you.
