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-   -   Trim Position Indicator (https://vansairforce.net/community/showthread.php?t=146843)

n74846 02-19-2017 02:32 PM

Trim Position Indicator
 
My trim position indicator has been erratic and inaccurate for a while, and now the indicator just sits at the bottom of the scale. Trim operation is fine so power (White wires) are OK. Before I go trouble shooting, my understanding is that if the connection/wires are bad I would see a red X over the scale, which I do not. Any thoughts before I start taking things apart?

tomkk 02-19-2017 03:03 PM

I had the exact same problem. My problem was caused by a bad connection in the trim motor connector back in the tail cone. I had that thing in and out several times before I finally got it fixed.

n74846 02-19-2017 06:12 PM

So your connectors were still the culprit. That's where I'll start then.

sglynn 09-05-2018 05:03 PM

Trim Indicator Jumping
 
Steve
What finally fixed your trim indicator erratic problem. I have it to. I'm not sure if my wiring got screwed up or if the trim motor is damaged or if I merely need to clean the connectors. My indicator jumps from full left to full right rather than moving smoothly along its throw.

Can the wht/green, wht/orange, wht/blue wire be mapped to the wrong pin and cause this?

thanks

Mich48041 09-05-2018 07:09 PM

To sglynn,
I think that you are correct about wires being connected wrong.
Try switching the wht/green and wht/blue wires with each other.

JBPILOT 09-05-2018 08:40 PM

Wire crimping - -
 
is the likely issue. I have done mine maybe 3 times in 9 years. Those tiny wires are hard to get perfect crimps. I went against the instructions and soldered mine this year. Works perfect now. Not suggesting, just what I did.

n74846 09-05-2018 08:43 PM

I finally gave up trying to track down the issue and fly without the indicator. I visually confirm take off position before each flight, then the rest is feel. At some point I will replace all components.

JBPILOT 09-06-2018 06:27 AM

Steve- -
 
When mine failed last time, it did the same as yours. Indicator went to bottom. If it was working at some point, then you just need better connections at the connector(s). There is enough wire extra, I could cut mine 3 - 4 times and re-solder them if needed. Stop the problem. Make sure the wires have some free movement so they don't pull on the solder connection.

John-G 09-06-2018 06:58 AM

Steve -

Getting a good crimp on the tiny pins used for the trim motor's Molex connector can be problematic ... as a review of past VAF posts will reveal. Fortunately, I had tiny jaws for my crimping tool and have not yet had any issues to this point.

However, that said, should the wiring to that tiny connector ever show the slightest hint of trouble, I absolutely would NOT repair the offending pin(s) and reuse that tiny Molex connector. Instead, I would suggest considering converting to male and female pins used in the DB connectors. After crimping the new DB male/female connector pins in place, mate the pins and slide a piece of TIGHT fitting heat shrink tubing over the pins then shrink ... you will end up with a long lasting trouble free connection that can easily be taken apart later should the trim motor need repair. The heat shrink will shrink down tight around the pins and will prevent them from coming apart on their own. Food for thought.

Happy flying,

rvbuilder2002 09-06-2018 08:48 AM

Quote:

Originally Posted by John-G (Post 1286390)
Steve -

Getting a good crimp on the tiny pins used for the trim motor's Molex connector can be problematic ... as a review of past VAF posts will reveal. Fortunately, I had tiny jaws for my crimping tool and have not yet had any issues to this point.

However, that said, should the wiring to that tiny connector ever show the slightest hint of trouble, I absolutely would NOT repair the offending pin(s) and reuse that tiny Molex connector. Instead, I would suggest considering converting to male and female pins used in the DB connectors. After crimping the new DB male/female connector pins in place, mate the pins and slide a piece of TIGHT fitting heat shrink tubing over the pins then shrink ... you will end up with a long lasting trouble free connection that can easily be taken apart later should the trim motor need repair. The heat shrink will shrink down tight around the pins and will prevent them from coming apart on their own. Food for thought.

Happy flying,

Another option is to upgrade to the new servo tray which has an integral mount for a DB9 d-sub connector. This then utilizes the same pins but has the added benefit of easily separating the connection if needed.


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