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RetiredRacer

Well Known Member
When first doing the panel, I wired the ray allen trim up to their LED display. It only showed the bottom light, and did not change. So when I installed the Dynon D180, I wired the Ray Allen unit to the D180 as pr Dynons instructions.
But the Dynon does not seem to recognise the trim unit, when using the Dynon's installation instructions.
 
Early in our build, I can remember someone posting about having the same problem. I've done search's, but have not been able to locate the post, or any other post with a similar problem.

Thanks for any help you can give.

Bob
 
Just a thought! You mentioned replacing a connectiong plug on a fuse. Are you using the +5V breakout voltage from the Dynon to power the trim indicators? The +5 volt is where you power your Manifold Pressure Sender and various other potentiometers. I don't believe they would work on 12 volts.
 
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The trim sensor is just a potentiometer. It has three wires (not counting the trim motor wires). One side of the pot gets grounded (the Blue one), the other side of the pot (the Orange one) gets the +5 volt sensor power out of the D180 and the wiper of the pot (the Green one) goes to the GP input of the Dynon. You then need to calibrate the D180 to the pot and thats all there is too it.

Either you have a bad sensor or the wiring is wrong.

To test the sensor, connect an OHM meter across the Blue and Orange Wires with nothing else connected to the sensor. You should read the full resistance of the pot inside (I think it is 1K ohms but I can't remember, it will either be 1K, 5K or 10K)

If this test good, take the ohm meter and connect one side to the Green wire and one side to the Blue wire.

Then take a 9 volt battery and use it to cycle the trim motor back and forth by connecting it to the two White wires. You can flip the polarity to get the trim motor to reverse.

As you cycle the trim motor back and forth, you should see the resistance between the Blue and Green wires change from max (whatever you got for the resistance above...either 1K, 5K or 10K) to zero.

If these ohm test work out, then the problem is in the wiring. If they don't, it is a bad sensor.

There is a remote chance that your Dynon is either not putting out 5 volts or the GP input you are using is bad. I doubt this is the case since the 5 volt supply is current limited and the GP inputs are pretty robust.

Make sure that if all the wiring and ohm test check out that you have the correct GP input selected for your trim indication and that you have properly calibrated the input.
 
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Thanks guys, You might be onto something here. It was about 12 months ago this wiring was done, checked and re-checked. But I cannot remember it being connected up to the +5 v. I may be wrong, but I don't remember it.
Hopefully I'll get a chance to duck out to the hanger this weekend to check

If it has been connected up to 12v, would it be damaged?

The aircraft has been flying since April and I haven't worried about the trim indicator, but the wife starts her training soon, so I want it working for that.

Thanks again

Bob
 
My guess is that you probably haven't damaged anything if in fact you are hooked into the ships power. I imagine there have been several people who have changed to the Dynon internal trim position incdicators and overlook the +5V bus power source change for the normal 12 volts the Ray Allen indicators use. I imagine that the Dynon would disregard the input as invalid, but I certainly could be wrong.
 
Dynon has stated before somewhere that 12v won't smoke their input but it will put the signal too far out of range for it to calibrate.

12v across the pot inside the servo will cause more current to flow thru it but not enough to damage it. Since that is the default voltage for Ray Allen stuff, it should be fine.

One way you could smoke the pot inside the servo is by miswiring the voltage to the wrong lead. This could smoke it fast depending on where the wiper was on the pot.
 
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