[cbraxton]

Looks like I also had the resistance servo motor in my Schwinn 420 elliptical die, and of course have found out the part is NLA.  (According to fitnessrepairparts.com, which pointed me to this forum, the early and late model 420 both use the same motor.) Guess I'll have to keep an eye out for a good used one. In the meantime I might see if I can kludge up a way to manually set the resistance at mid-range so the machine is at least somewhat useable.

Looks like this is a pretty common failure. If I wind up replacing this machine I'd think twice about getting another Schwinn given the lack of support.

[cbraxton]

It looks like finding a replacement motor is going to be a challenge.

In the meantime I have fastened a turnbuckle between the magnet assembly and the frame so the resistance level can be mechanically adjusted. With this the machine can be used by setting a single desired resistance level for the workout session. If I can't find a replacement OEM motor It may be possible rig up a powered drive of some type with its own switch, separate from the Schwinn control panel, to permit manual adjustment while in use.