KNS-80/KNI-520 encoder bad?

OK... question for those in the know. I've got a KNI-520 connected to a
KNS-80 RNAV. The DME, localizer, and RNAV *distance* work fine, but the VOR needle
doesn't deflect properly recently. If you try to center it, it won't stay in the
center, but rather will twitch from pegged on one side to pegged on the other with a
very small (5 degrees) change in the OBS ring. I'm thinking that since the head
doesn't have a NAV converter, but rather tells the KNS-80 where the OBS is with
encoder lines, that one of those lines might be broken/intermittent. That would mean
it would think the head is in 1 of 4 (2?) positions, rather than somewhere in between.

Thoughts on this? Anyone fixed such a thing? I haven't torn into the wiring
yet and suspect it's intermittent (read: difficult to find).

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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