i work in the consumer electronics industry, and i see a lot of bad drive mechs, especially the samsungs. spindle motors in samsung drives are by far the largest number of failures, with lasers a close second (if the laser lights and tries to focus, it's probably ok). you can try to salvage a spindle motor from another similar samsung drive, or just get a new mech. they're about $30 from samsung. just make sure you get the part number off of the drive. there should be a barcode sticker, and the part number is buried in the number on the sticker. it begins with an A and another letter (usually AK or AH), then there's 7 digits and another letter. that's the part number. i don't have a sticker in front of me, but it usually has something long like 20 characters on it, so i'm going to give an example that might not be totally accurate, but should be enough information for you to recognize the part number...
number on sticker:
C038475AK9701234B29F83727
embedded part number:
AK97-01234B
hth