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Trim troubleshooting - new installation

C

CTCole

Active Member
I've just powered up the -12iS for the first time and was configuring the G3X. The trim does not operate, nor does the PFD show trim or flap position (the flaps do work). I've verified that 12V applied to the trim power wires (in the WH-P30-1 cable that goes back to the trim motor in the stinger) where they connect into the main power center AV-60000 runs the trim motor. The stick-mounted Comm flip-flop switches work, so at least those connections are okay. I'm stumped about what to do next for troubleshooting. Any suggestions?

-CT Cole
 
I'm not familiar with the RV-12 per se, but I think the trim motors are similar across the Van's models. As I recall, there are two power wires, one ground, and the trim position wires. They're all pretty tiny and it's easy to get those color codes mixed up. If you're not getting movement or a trim position, my first guess would be that those got mixed up back there. It wouldn't be the first RV to have that issue.

If those are right, confirm you've got power back there when the trim button is bumped. Measure voltage at the tail nearer the trim motor itself--assuming there's a connector back there. Chances are that the connections are incorrect (or you've got a bad trim motor, which is less likely). If you don't have voltage back there, you've got to find where there's an open or improper connection further back in the plane.
 
Thanks, Dave. The wires going to the trim motor are good-- correctly located in the D-subs, good contacts, etc. -- I verified that by running the trim motor with a separate battery, as well as inspecting the wires & connectors visually and comparing them to the wiring diagram.

The problem is upstream of where the trim cable D-sub connector plugs into the power module (A-60000). The 12iS is different from other RVs, as the trim signals come from an Arduino integrated circuit in the power module, to which the autopilot & control sticks are also connected. I'm lost on how to troubleshoot that IC.

--Chris
 
I have the Dynon avionics so I probably can't be of much help. However, in the Dynon setup the trim control input to the AV6000 goes through the SV_PANEL autopilot module if you have that installed. Is the same true for Garmin avionics?

PS:
1. Have you checked that the control stick trim buttons ground the correct pins of the 50-pin connector on the AV6000 when you press them? Wiring faults in the supplied harness appear to be common. There were two faults in mine.
2. If you've ever shorted the trim motor output wires from the AV6000 9-pin connector, or shorted one of them to ground, then the Pololu module in the AV6000 is likely to have blown. It should be easy enough to replace.
 
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I've gone through the G3X autopilot configuration, though I don't fully understand how it uses both the pitch servo and trim motor to control pitch. So far that hasn't provided any trim function. I've only pulled the 9-pin D-sub from the power module (it checks out okay), and haven't pulled the 50-pin plug, as I don't understand what I'd be testing there, or how.

--Chris
(p.s is that an African or a European swallow?)
 
Chris,

I'm far from an expert on the G3X but I have been trying to get my Aileron Trim functioning in some form too. You mentioned you got through the autopilot configuration. I'm not sure of the extent of what you meant by that. The specific inputs need to be configured for the position since there are a few sets of inputs on the GEA24 so I'm not sure if you did that or not. I don't have my wings attached so I'm missing my connections through my roll servo so I can't do quite as much checking as I would like at this point. I may manually control the trim motor just to see if the position input is working though.
 
CTCole said:
I've gone through the G3X autopilot configuration, though I don't fully understand how it uses both the pitch servo and trim motor to control pitch. So far that hasn't provided any trim function. I've only pulled the 9-pin D-sub from the power module (it checks out okay), and haven't pulled the 50-pin plug, as I don't understand what I'd be testing there, or how.
Click to expand...

I haven't completed my RV12 and although I had tested most of the avionics, I hadn't tested the trim motor because I haven't attached the tailcone yet. So I decided to make up a temporary cable to connect the trim motor assembly to the AV6000. It turns out that my trim motor doesn't respond to the control stick buttons either. I'll investigate it and let you know what I find. The Arduino on the AV6000 that controls the pitch trim must be powered and running because it also controls the dimming functionality, and the dimmer control is working.

There is a trim speed potentiometer on the AV6000. I'm wondering whether it might be set to minimum, and if so whether that would select zero trim speed - I can't tell without knowing how the Arduino is programmed.
 
I got my trim motor working. The fault was trivial: I hadn't inserted some pins in a D-type connector far enough.

I checked out the trim speed potentiometer, which is a square blue component on the back of the AV6000. Looking from the front of the AV6000 it is in the top left corner. When the screwdriver slot is turned fully clockwise it supplies the full 13V or so to the trim motor when I press one of the trim buttons. Turned fully anticlockwise it provides a PWM signal that averages about 6.5V.
 
If your trim is connected through a GSA 28, you don't want to use any kind of PWM signal - see your G3X installation manual for the details.
 
CTCole said:
I've gone through the G3X autopilot configuration, though I don't fully understand how it uses both the pitch servo and trim motor to control pitch. So far that hasn't provided any trim function. I've only pulled the 9-pin D-sub from the power module (it checks out okay), and haven't pulled the 50-pin plug, as I don't understand what I'd be testing there, or how.

If you have G3X but no autopilot, you need a jumper plug in place of the Garmin pitch servo to enable manual pitch commands to reach to trim servo.
Click to expand...
 
I've gone through the configuration instructions in Ch 35 of the G3X Installation Manual, at least as far as they can be done on the ground. That includes some settings for the autopilot. I've also tried the blue potentiometer knob in different positions (extreme left & right, middle). The trim does run through the autopilot pitch servo, which confuses me.

In talking today with Tony Kirk at Van's, who drew some of the wiring diagrams for the RV-12 (and is building one, too), he recommended making a couple of test jumpers with D-sub pin ends (one M, one F) and testing continuity with a multimeter, at pin locations for trim functions on the 50-pin D-sub that mounts onto the power module. These would include pins #10 and 50 (to the trim motor) as well as those coming from the control sticks. This would be to make sure the pins are in the correct locations. So I've got some pins on order to try that.
 
I would disconnect the 9-pin trim connector from the AV6000, substitute a 9-pin plug with wires attached to pins 1 and 2, and test whether pressing each of the trim buttons gives you 12V between those wires.
 
Also be aware with the G3X installation with autopilot, you must have the Pitch Servo wire harness connector attached to the GSA 28 or have the Garmin Servo Removal Adapter connected to the wire harness connector so the trim servo power will pass through.
_
 

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Configuration issue?

CTCole said:
I've just powered up the -12iS for the first time and was configuring the G3X. The trim does not operate, nor does the PFD show trim or flap position (the flaps do work). I've verified that 12V applied to the trim power wires (in the WH-P30-1 cable that goes back to the trim motor in the stinger) where they connect into the main power center AV-60000 runs the trim motor. The stick-mounted Comm flip-flop switches work, so at least those connections are okay. I'm stumped about what to do next for troubleshooting. Any suggestions?

-CT Cole
Click to expand...

We have a test rig with a trim motor and control stick and check every system for proper trim operation. We verify that the trim motor is not only moving, but that the auto trim settings are also correct and that all of the movement matches the position indicator on the screen.

What first catches my attention is that you do not have the flap or trim position indicators on the screen. To me this suggests that some of the setting could have been changed resulting in the system not working. Start by going to Van's website and re-download the RV12iS configuration files. There is a read-me that will walk you through installing this file. This should at a minimum bring the position indications back on the screen. If this doesn't work, please give us a call at SteinAir so we can walk you through this. There are a lot of different pieces to this trim system, so i think it would be best for us to guide you through it.

p.s. The above is assuming that everything is hooked up and everything else is working properly. If you are having other problems, please let me know because this could be a symptom of that.
 
FlyingSquirrel said:
Configuration issue?



We have a test rig with a trim motor and control stick and check every system for proper trim operation. We verify that the trim motor is not only moving, but that the auto trim settings are also correct and that all of the movement matches the position indicator on the screen.

What first catches my attention is that you do not have the flap or trim position indicators on the screen. To me this suggests that some of the setting could have been changed resulting in the system not working. Start by going to Van's website and re-download the RV12iS configuration files. There is a read-me that will walk you through installing this file. This should at a minimum bring the position indications back on the screen. If this doesn't work, please give us a call at SteinAir so we can walk you through this. There are a lot of different pieces to this trim system, so i think it would be best for us to guide you through it.

p.s. The above is assuming that everything is hooked up and everything else is working properly. If you are having other problems, please let me know because this could be a symptom of that.
Click to expand...
Thanks, Joshua. I'll re-install the configuration file. It's reassuring to hear the system is checked with your test rig.
 
FlyingSquirrel said:
Definitely let me know if this resolves your problem or not.
Click to expand...
I am having the same problem. With mine the auto pilot is not working,(there is power to it as the back light comes on when the master is turned on.) but I do have trim indications on the PFD. The WH-30-1 was removed from the back of the AV-60000 and 12 volts was applied. The trim worked fine. I plugged the WH-30-1 back in and the trim indication had changed. ARGH, what a head scratcher.
 
rwh said:
I am having the same problem. With mine the auto pilot is not working,(there is power to it as the back light comes on when the master is turned on.) but I do have trim indications on the PFD. The WH-30-1 was removed from the back of the AV-60000 and 12 volts was applied. The trim worked fine. I plugged the WH-30-1 back in and the trim indication had changed. ARGH, what a head scratcher.
Click to expand...
Just sent you a DM.
 
I’m also having a problem with my pitch trim stick buttons. Mine is a Dynon system, RV-12iS However, the auto pilot works fine and auto trim works fine. The green lights on the switches don’t illuminate.


The green switch lights and auto pilot disconnect button illuminated once when I first powered up the system but never came on again.
  • Now that the plane is ready to fly, no switch lights
  • Auto pilot works fine, auto pitch trim works fine
  • Pitch trim buttons on both sticks do nothing
  • All other buttons on sticks work fine
  • External Brightness voltage remains 0.0, brightness pot does nothing
  • Did setup per Van’s readme
Thanks
Paul
 
Paul A said:
I’m also having a problem with my pitch trim stick buttons. Mine is a Dynon system, RV-12iS However, the auto pilot works fine and auto trim works fine. The green lights on the switches don’t illuminate.


The green switch lights and auto pilot disconnect button illuminated once when I first powered up the system but never came on again.
  • Now that the plane is ready to fly, no switch lights
  • Auto pilot works fine, auto pitch trim works fine
  • Pitch trim buttons on both sticks do nothing
  • All other buttons on sticks work fine
  • External Brightness voltage remains 0.0, brightness pot does nothing
  • Did setup per Van’s readme
Thanks
Paul
Click to expand...
If the trim motor works properly when you send commands from the AP control head the motor wires are connected correctly, but the sticks are not sending trim commands to the AP control head for some reason. I would start by checking the 5A trim/start power fuse. This fuse powers the Arduino that controls both the trim system, including sticks inputs, and the canbin lighting. The symptoms you are describing are almost all related to that Arduino, and the most likely failure is that fuse being blown. There are 2 wires tied into that circuit for the CPU fans. Those can easily short if you get excited and turn the system on before everything is fully installed.

Start by checking that and DM me what you find out.
 
Update -- with good advice from Tony Kirk at Van's, I ran a bunch of continuity & voltage tests on the trim system. Everything checked out fine (including the fuse), leading him to conclude the Arduino must be faulty (the dimmer, which is also controlled by the Arduino, is non-functional). Replacement would be the definitive test, but I've been waiting a couple months for that.
 
CTCole said:
Update -- with good advice from Tony Kirk at Van's, I ran a bunch of continuity & voltage tests on the trim system. Everything checked out fine (including the fuse), leading him to conclude the Arduino must be faulty (the dimmer, which is also controlled by the Arduino, is non-functional). Replacement would be the definitive test, but I've been waiting a couple months for that.
Click to expand...
That sounds like the correct answer to me. It's important to check everything else out first though, replacing parts should never be a first step. We have had a few of these issues in the shop, with no clear cause, and swapping out the board was the solution.

Let me reach out to some of my colleagues at Van's on Monday and see if 8 can get you some traction. They have some legal guidelines due to chapter 11, so I can't make any promises, but maybe I can shake something loose for you.
 
FlyingSquirrel said:
That sounds like the correct answer to me. It's important to check everything else out first though, replacing parts should never be a first step. We have had a few of these issues in the shop, with no clear cause, and swapping out the board was the solution.

Let me reach out to some of my colleagues at Van's on Monday and see if 8 can get you some traction. They have some legal guidelines due to chapter 11, so I can't make any promises, but maybe I can shake something loose for you.
Click to expand...
Thanks, Joshua -- that would be welcome.

-Chris
 
CTCole said:
Thanks, Joshua -- that would be welcome.

-Chris
Click to expand...
I talked one of my colleagues at Van's today. I made them aware of this thread and it was sent to the support team as well. They recommended reaching out to the support team again to get things moving.
 
FlyingSquirrel said:
I talked one of my colleagues at Van's today. I made them aware of this thread and it was sent to the support team as well. They recommended reaching out to the support team again to get things moving.
Click to expand...
Joshua, I talked with Tom at Van's Builder Support, and he's going to try to find out more about getting replacement Arduinos programmed for people that need them. Sorta sounds like something that just never quite gets on the To Do list of anybody that can actually take action. Here's hoping.

-- Chris
 
I'm having similar issues. Trim switches on the sticks aren't working, but I may be getting a little ahead of myself. I have yet to upload the config files. Trim motor works when battery power is applied, but stick buttons do nothing. Trim position appears on the G3X.
 
Burndout11 said:
I'm having similar issues. Trim switches on the sticks aren't working, but I may be getting a little ahead of myself. I have yet to upload the config files. Trim motor works when battery power is applied, but stick buttons do nothing. Trim position appears on the G3X.
Click to expand...
Burnedout11,

I originally thought the same thing about configuration files, so I waited until I uploaded them. I still had the issues after the upload. I wish Van's would be giving some type of feedback.

Paul
 
Paul A said:
Burnedout11,

I originally thought the same thing about configuration files, so I waited until I uploaded them. I still had the issues after the upload. I wish Van's would be giving some type of feedback.

Paul
Click to expand...

Kind of hard to have a first flight with pitch trim being inop. I guess a call to Vans on monday will be in order.
 
Burndout11 said:
Kind of hard to have a first flight with pitch trim being inop. I guess a call to Vans on monday will be in order.
Click to expand...
You should also check to make sure that pins 1 and 2 (Garmin and Dynon without an AP module) are populated on the 9 pin connector on the back of the AV 60000. If you have. Dynon system with the AP module check to make sure pins 6 and 9 are in the correct place.
 
FlyingSquirrel said:
You should also check to make sure that pins 1 and 2 (Garmin and Dynon without an AP module) are populated on the 9 pin connector on the back of the AV 60000. If you have. Dynon system with the AP module check to make sure pins 6 and 9 are in the correct place.
Click to expand...

I’ve got garmin w/AP
 
Burndout11 said:
I’ve got garmin w/AP
Click to expand...
check to make sure you have pins 1 and 2 on the 9 pin populated. I have seen people miss the connector supplied with the Garmin harness and plus the WH-P30-1 harness directly in. That would make the motor run when you applied power directly, but the system doesn't work without those wires.

It's a relatively quick easy check and I guarantee the Van's team will ask you to check it as well.
 
FlyingSquirrel said:
check to make sure you have pins 1 and 2 on the 9 pin populated. I have seen people miss the connector supplied with the Garmin harness and plus the WH-P30-1 harness directly in. That would make the motor run when you applied power directly, but the system doesn't work without those wires.

It's a relatively quick easy check and I guarantee the Van's team will ask you to check it as well.
Click to expand...

I’ve got them populated. I’m going to break out the multimeter tomorrow and start checking things.
 
Word from Van's is that Engineering has taken up this problem (apparently several builders' Arduinos have failed) and they are working on a solution. They are also testing replacement units and hope to send them out fairly soon.
 
So a funny thing happened today. I updated the G3X software to the most recent version and magically the trim motor started working. I don’t know if that made the difference but that’s the only thing that changed.
 
Burndout11 said:
So a funny thing happened today. I updated the G3X software to the most recent version and magically the trim motor started working. I don’t know if that made the difference but that’s the only thing that changed.
Click to expand...
What version did you have before? 9.31? And you replaced it with 9.33?
 
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