DIY rear compass cabling fix

[Logger]

I guess there is no reason to do the mod unless you are having issues.
My noise level is a good deal less than yours ScrappyMavic at 170 pk2pk. This is seemingly still enough to give me compass reversions at times and a couple of TBEs before the firmware tweak. Additional geographic factors come into play as I understand it.

Maybe the lack of twisting was simply an oversight on the production line which was supposed to have been done.

 

[Ewan Morrish]

Mine was purchsed on January 5th and it also has 200 units PP of noise when flying in sports mode.
I have not had any problems with my Mavic so I am not sure if I want to pull it apart just yet.
It is kind of surprising that engineers of the caliber and experience that DJI uses did not think of twisting the wires from the start.

Hi all, just to confirm this has fixed my Mavic also. I did 4 rotations on each back arm. No more compass redundancy switch messages.


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[Logger]

This is great new Ewan. So seemingly a 100% strike rate so far. How old is your unit approximately?

 

[Ewan Morrish]

This is great new Ewan. So seemingly a 100% strike rate so far. How old is your unit approximately?

Must have been one of the 1st batches. Got mine delivered late October.


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[Logger]

Good to know.
So we have 3 known noisy units shipped prior to to mid November. Scrappys, Ewans and mine. Then RobbyG's purchased in early Jan. This one could feasibly have been shipped mid December, depending on where purchased. So mid Dec looks like when the change occurred.

 

[Ewan Morrish]

Good to know.
So we have 3 known noisy units shipped prior to to mid November. Scrappys, Ewans and mine. Then RobbyG's purchased in early Jan. This one could feasibly have been shipped mid December, depending on where purchased. So mid Dec looks like when the change occurred.

December is when the firmware updated and stated posting messages in the Go App 4. So I'd say DJi knew of the issue around that point.


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[npmullins]

Hi all, i have been getting the compass redundancy switch error message, in sport mode with aggressive maneuvers, i did the wire twisting mod last night, yet to do the test flight.

A word of warning to others how are yet to do this, i found the unclipping of the plastic clips on the front nose of the top plate very difficult to undo. I used a plastic prying tool and still struggled for 5 mins to make it pop open. But once i was in the arms came off every easily after removing the 3 screws.

 

[Logger]

Welcome @npmullins . So many Questions...
Have you had a chance to test it yet? Sounds like you did the full process too which is a first in this thread.
By removing the top - did you take advantage of being wind the cable all the way back to the circuit board?
In what state did you find the cables upon popping the top? Were the wires tucked into grey the loops near the rear arms.
Were they unwound as one might expect, if you were getting compass switching?

Interesting about the difficulty you had with the from clips. Did you start by opening the rear end first as @Thunder-drones has recommended?

 

[Mavicsailor]

I was curious as to what my noise was. This should give another data point. I picked up mine on 1/20/17. Looks like about 70 p2p for the back compass max current in sports mode.

 

[Egika]

Which software ate you using to evaluate the data? In the DJI viewer I only have compass x,y,z to choose from...

 

[Mavicsailor]

Which software ate you using to evaluate the data? In the DJI viewer I only have compass x,y,z to choose from...

Search this forum for CsvViewer by BudWalker. Excellent tool

 

[Egika]

OK. Thanks!
Just checked mine (ordered and received mid January).
On full power (current maxing at 23A), I get 60 p2p for the back magnetic sensor .

 

[Mavicsailor]

OK. Thanks!
Just checked mine (ordered and received mid January).
On full power (current maxing at 23A), I get 60 p2p for the back magnetic sensor .

Looks like ours has the twisted wire minimizing compass interference. I was prepared to do surgery!

BTW, if you click copy to system clipboard in CsvViewer, you can easily paste the graph directly into the thread. BudWalker pointed that out to me to make it easer after I was taking screen shots of everything.

 

[Egika]

Yeah, posting from the phone

 

[msinger]

Which software ate you using to evaluate the data?

You can find CsvView here.

 

[Egika]

Thanks. Already used it - see the screen pic above :-D

 

[Logger]

Yours is looking good too @Egika.
@Mavicsailor Thanks for the tip to copy and paste direct to this thread with CsvView Was not aware of we could do this without the need to save an image file first.

The timeline of your deliveries and quiet rear compass traces, bode well for this being a workable fix.

 

[Logger]

This is what mine looks like BTW. As it happens its in for a service to deal with this and an unrelated matter. So I am interested to see where it ends up when/if I get it back

 

[Mavicsailor]

Yours is looking good too @Egika.
@Mavicsailor Thanks for the tip to copy and paste direct to this thread with CsvView Was not aware of we could do this without the need to save an image file first.

The timeline of your deliveries and quiet rear compass traces, bode well for this being a workable fix.

I agree. Looks like your suggested fix will work well to bring the noise close to the levels seen in the factory solution. Thanks for taking the time to document this for others!

While flying in sport mode at full speed I monitored the sensor/compass number. Another measurement of noise but real time. Best I could tell, it was under 100. I've never seen the compass switch.

 

[Ewan Morrish]

I agree. Looks like your suggested fix will work well to bring the noise close to the levels seen in the factory solution. Thanks for taking the time to document this for others!

While flying in sport mode at full speed I monitored the sensor/compass number. Another measurement of noise but real time. Best I could tell, it was under 100. I've never seen the compass switch.

Yes this is a fantastic find. I was about to send mine in for repair! Very happy now in have a Mavic that I can without errors popping up all the time.


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