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  #1  
Old 09-14-2009, 07:40 PM
Jaknjoan Jaknjoan is offline
 
Join Date: Jan 2005
Posts: 227
Default RV-12 Trim

This is directed to Stein, or anyone else that can give me some insight.

After powering up my system this past weekend, everything appears to be working with the exception of my stabilator trim. I'm getting power back there to the servo, but very little. Question .... is the full range of the potentiometer trim about 3/4 of a turn? That's all I can get. In one extreme direction, pressing the trim control switch it makes no noise and no movement. In the other extreme direction the motor makes some noise and is trying to move the trim, but is able to move the shaft maybe 1/8 - 1/4 inch if I hold it long enough. There is no resistance since the trim tabs are off and the pushrod is just laying on something.

Any suggestion in where I go from here.

JT
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  #2  
Old 09-14-2009, 08:28 PM
Peterk Peterk is offline
 
Join Date: Mar 2008
Location: Texas
Posts: 1,378
Default Trim

Stein did not do the board. I had the same prob. You have a low voltage problem and need to turn your blue dial as far counterclockwise as possible. Even then you may need a battery charger on it. Your battery is doing 12 volts, your flying will more likely do 14. My dial was turned completely off...all the way clockwise.
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  #3  
Old 09-14-2009, 08:31 PM
JBPILOT JBPILOT is offline
 
Join Date: Nov 2007
Location: Jesup, Iowa
Posts: 1,632
Default I had an actual motor problem

If I laid the motor on top of the tail, not hooked up to ANYTHING, it would run in up and down cycles. Was binding inside. I would try that. Did you follow the instructions and hook it up to a battery from a 12v drill and run it that way ?

John Bender
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  #4  
Old 09-14-2009, 08:36 PM
Jaknjoan Jaknjoan is offline
 
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Default

Quote:
Originally Posted by Peterk View Post
Stein did not do the board. I had the same prob. You have a low voltage problem and need to turn your blue dial as far counterclockwise as possible. Even then you may need a battery charger on it. Your battery is doing 12 volts, your flying will more likely do 14. My dial was turned completely off...all the way clockwise.
My battery was fully charged, showing about 13.1 volts (using a good meter). It is possible that 14.6 volts would make it more active, but I hardly believe that is the problem because when I was originally testing the servo I operated it with a 9 volt battery and had strong but slower than normal movement. I have a fair amount of experience with these servos as this is not the first or second RV that I've built.
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  #5  
Old 09-14-2009, 08:39 PM
Peterk Peterk is offline
 
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Location: Texas
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Default trim

you could also consider pulling the red and white pins in the d-sub up front and see if you get better movement (in other words, a board problem). That was going to be my next step.
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  #6  
Old 09-15-2009, 07:28 AM
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Geico266 Geico266 is offline
 
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Location: Huskerland, USA
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JT,

What voltage does the Dynon indicate when you fire the system up? Is your battery ground lug tight?

A couple of builders that have had trouble run a Battery Minder / 2 amp charger overnight to top off the battery then run the test. The trim should however, work in the lower voltage (12v-13v) mode so you can adjust the trim prior to take off.
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  #7  
Old 09-15-2009, 01:09 PM
Jaknjoan Jaknjoan is offline
 
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Default

Quote:
Originally Posted by Geico266 View Post
JT,

What voltage does the Dynon indicate when you fire the system up? Is your battery ground lug tight?

A couple of builders that have had trouble run a Battery Minder / 2 amp charger overnight to top off the battery then run the test. The trim should however, work in the lower voltage (12v-13v) mode so you can adjust the trim prior to take off.
Larry,

I have not had time to work on my problem this morning until now, but my master voltage on the Dynon is 12.2 volts. I had used a battery minder and brought the voltage to the max that the charger will charge it. I really don't think the problem is my voltage, because, as previously said, the servo worked fine using a 9 volt battery and with 12+ volts it should have all the power the servo will ever need. The power appears to be going back to the servo, but it is only a trickle in relation to what the servo needs. I don't know whether it's the wiring or something else. Peterk had a suggestion of disconnecting some wires running to the servo in the Tunnel harness that I may try if nothing else works. My ground cable is tight and sound.


JT
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  #8  
Old 09-15-2009, 02:15 PM
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Brantel Brantel is offline
 
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Default

What is the voltage at the servo under a load?
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  #9  
Old 09-15-2009, 04:22 PM
Jaknjoan Jaknjoan is offline
 
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Default

Quote:
Originally Posted by Brantel View Post
What is the voltage at the servo under a load?
I just finished checking the continuity of all 5 wires originating at the servo to their pin locations in the 37 sub-D connector going into the Av board. All show continuity. (I had help from my wife who handled the servo end with the ohm meter and I used a long wire at the instrument panel) I have checked the voltage at the servo when the trim switch is activated in the up and down mode, at appears to be about 6.2 to 6.5V without a load. I disconnected the servo from the actuating arm and was able to get full movement in and out using a Duracell 9 volt battery. It would seem to me that the potentiometer should allow 12 volts to get back to the trim servo when it is turned all the way in one direction, and I'm only getting just over 6V.

Right now I'm thinking the board may be responsible. I have not yet contacted Van's about my problem.

JT
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  #10  
Old 09-15-2009, 06:25 PM
Peterk Peterk is offline
 
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Default Trim

JT,

Let us know what you find out. I don't think any of us are completely satisfied with the
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