Just in case anyome else fixes TM100s... As is well-known, the track0 sensor in these drives is a microswitch. It's a standard V?-size one, but iwth a low operating force. One of mine failed (in an HP9836, if it matters), and I've found that RS (not Radio Shack, but http://www.rswww.com) 472-8005 is a perfect replacement. It's got the same connecitons (simply move the wires over tag-to-tag), and fits the original brackets with no problems. -tony