Saturday, September 5, 2015

trim position indicator debugged

Getting the trim motor connected wasn’t too bad.  I double and triple and quadruple checked the white wires to ensure that I was trimming in the proper direction. I then used the Product Acceptance Procedure to further verify that all linkages and trim directions were as directed.  I was then disappointed to discover that the trim position indicator wasn’t working.  Rummaging around in the VAF, I found the hidden menu item to do a calibration for the trim position indicator and I thought my problems were solved.  Alas, it was not to be the case.  Running through the calibration screen, the computer dutifully noted that the voltage on the sense pin remained about 5 v the entire range of operation.

Yesterday, I tackled that problem.  The biggest issue is that I am 55 yrs old and have had to wear trifocals for over 20 yrs now.  Sitting on a stool under the tail of the plane requires looking up to see the trim motor and its various wires.  That means that I’m looking through the ‘distance’ portion of my lenses and that everything is hopelessly  out of focus.  Did you recall that I’m 55?  That means I can’t crane my neck back far enough to get the ‘near’ sense to bear.  (BTW, it is possible to order “mechanics” glasses that have the ‘near’ lens ground at both the bottom and the top of the lens.  Unfortunately, they run about $500, and no, you can’t get trifocals in that arrangement.)

Eventually I was able to find a stool of the proper height, an acceptable head angle and sufficiently bright light source that allowed me to find a bent pin that wasn’t making contact.  In the process of trying to strip the wire for a new micro connector, I promptly ruined 2 “ by tearing through the soft insulation.  Sigh.  I soldered an extending replacement, heat shrinked (shrunk) insulation over it and eventually got everything reassembled.

Back to the cockpit, powered up, found the magic screen and did the routine.  This time the voltage on the sensed line obediently changed with position, and viola!, another bug taken care of.  On to the rear windshield!


IMG 4632

functional Trim Position Indicator

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