SnapAppliance tried to contact every one that had a 240gig and greater to replace the MB's. Units that were <240gig were not repaired and they made NO attempt to do so. If one was sent in for repair it got the repaired boards. The smaller drives did not present a problem. The 10 ohm resistor dampended a coil and made the drives settle down, (seek). Without it every time you rebooted it ran fsck, and would report error while in use.
http://www.northwesttechnical.com/ has parts for snaps, the 4100mb is $225. I would buy another one on ebay for parts or build your own.
If you want a NAS that has some ump, look at the 4500. The will handle 50+ users has a band width of 3000+MB/sec, 2 gigE lan ports.