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-   -   GRT Sport EX display goes crazy once it sees static pressure???!! (https://vansairforce.net/community/showthread.php?t=183286)

Kooshball 06-06-2020 02:52 PM

GRT Sport EX display goes crazy once it sees pitot pressure???!!
 
I?m in the final stage of install and testing on the panel upgrade which includes an AV-30, GRT Sport EX, ADSB in/out and MGL tach / MP.

All the wiring was done this week and all units behave normally except the GRT sport EX but only once it sees pitot pressure.

I setup a leaf blower to give 45-60 kts of airspeed into the pitot tube and then and only then did the GRT display start displaying all kinds of vertical lines. When airspeed is removed the display goes back to normal.

Has anyone here encountered this? If so, what was the problem and the solution?

Pic below and I have a video as well. Thx!

https://ibb.co/hVf8rL6

<a href="https://ibb.co/hVf8rL6"><img src="https://i.ibb.co/hVf8rL6/901113-F3-F239-4-ACC-8-D30-02-CC2-FF74-BA5.jpg" alt="901113-F3-F239-4-ACC-8-D30-02-CC2-FF74-BA5" border="0"></a>

rv8ch 06-06-2020 02:58 PM

Something's wrong
 
Quote:


That does not look like anything I've seen before. I think you will need to call GRT Avionics on Monday.

BobTurner 06-06-2020 03:10 PM

Well, this sounds crazy! Is it possible the pitot line is connected to a vent on the efis, or maybe the pressure sensor is broken inside, so there?s a strong blast of air pushing on a ribbon cable somewhere? I?d start by pushing some vinyl tubing over the pitot tube, tape over the drain hole. Hold the tubing in a U shape, add some water, lift up the free end. If the water in the U stays level, you?ve got a leak. Step two. Same vinyl tube over pitot, no water. Bring the free end of the tube into the cockpit, gently blow while watching the efis. Still go crazy? Can you hear air leaking anywhere?
BTW I cannot see picture.

BobTurner 06-06-2020 03:26 PM

Now I see photo. Call grt.

Mel 06-06-2020 03:28 PM

Is your leaf blower possibly electric? Looks to me like it could be interference from a nearby electric motor.

Kooshball 06-06-2020 04:07 PM

Quote:

Originally Posted by Mel (Post 1436875)
Is your leaf blower possibly electric? Looks to me like it could be interference from a nearby electric motor.

It is and we thought of that so we switched to compressed air from a distance so as not to damage anything. The same thing happened with compressed air. (The photo was actually of the compressed air failure mode) The AV30 behavior was normal in both cases.

Mike S 06-06-2020 04:14 PM

The screen is showing multiple alarms, have you looked to see what they are??

Press the "MSG" button to see what is making the little gnome inside the box unhappy. You can then inhibit each item and see if the lines go away with one of them.

Might find the issue ---- might not, but probably worth a try.

Kooshball 06-06-2020 04:18 PM

Yes, just voltage below 12V alarm and no GPS2 signal since I had that off.

Quote:

Originally Posted by Mike S (Post 1436892)
The screen is showing multiple alarms, have you looked to see what they are??

Press the "MSG" button to see what is making the little gnome inside the box unhappy. You can then inhibit each item and see if the lines go away with one of them.

Might find the issue ---- might not, but probably worth a try.


Mike S 06-06-2020 04:42 PM

Quote:

Originally Posted by Kooshball (Post 1436896)
Yes, just voltage below 12V alarm and no GPS2 signal since I had that off.

Well, as Thomas Edison would say----at least you know a couple things that are not the problem.

BobTurner 06-06-2020 06:09 PM

Since grt won?t be open until Monday, I?d pull it, take the cover off, and look around the airspeed sensor. Is there anything that moves? Are there any cables/connectors up against it? Gently push on the internal connectors, make sure they?re all seated.


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