An obscure IR Sensor Always Active (Always Reads 1) Problem and Solution  

An obscure IR Sensor Always Active (Always Reads 1) Problem and Solution

I spent the evening researching and repairing an IR sensor related problem and thought I'd document the problem and solution here in case someone else runs into the problem.  

Problem:  Autoload was working normally but stopped.  Looking at the Support->Sensor Info menu, the IR Sensor showed 1 even though there was no filament.

I followed many of the good suggestions in this forum.  My problem seemed unique because the mechanical sensor trigger was stuck in the "filament in" setting.  The steel ball that is normally pushed by the inserted filament was stuck in place, but filament was free to feed into the gear feeds.  Since the system had been working for a while, I temporarily (and ultimately) ruled out the magnets being place in the wrong polarity and I hoped that I didn't overtighten the screw on which the mechanical trigger pivoted (which, turned out not to be the case).  After loosing screws and pushing on things per various posts, I concluded that the steel ball was locked in place--probably by a piece of filament.  I played with spinning and pushing on the steel ball with some long tweezers until the something shifted and the steel ball shifted back into normal position.  However, something was now blocking the filament feed hole.  As you would guess, it was a piece of filament (black of course) that had broken off and had jammed the steel ball in place.  My mind went back to a recent occurrence where a spool of black filament ran out.  The gnarly end must have broken off in the feed hole and jammed between the housing and the steel ball. So the key take away is:

- If the IR sensor continuously reads "1"

- and If the mechanical lever that triggers when there is filament is stuck in place

- and if the steel ball doesn't seem to have and movement or play

There might be a broken piece of filament jammed between the steel ball and the steel ball's housing.  Try spinning the steel ball and pushing it with reasonable force to try and dislodge it and then use a small Allen wrench to push it through the feed hole (with the feed gear door open).