Thanks for the warm welcome, guys!
Welcome! I like the FW website, but it hasn't seemed to help me on my Twin Fami issues. Those disc drives are a pain!
The best FDS repair guide that I'm aware of is over at
FamicomDiskSystem.com. The drive in the Twin is the same as the drive in a plain old FDS, so the guide does apply. The drives are a huge pain in general, though. I was sure to buy mine "guaranteed working" from a trusted forum member.