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Mavic Pro Compass1 Compass2 Disconnected Repair

doodybutch

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THESE ARE HARDWARE FAULTS AND YOU HAVE TO REPLACE THE FAILED COMPASS PCB

compass2 replacement...

YOU NEED GOOD TOOLS AND A GOOD FINE TIPPED SOLDERING IRON TO DO THIS.


After a year with my Mavic Pro, I began to get compass errors and looking through (DJI Go 4 App) Main Controller Settings -> Advanced Settings -> Sensors -> Compass, it showed compass2 was "disconnected" This problem is widely described in this forum and elsewhere. The Mavic will fly with this error but you lose the redundancy of 2 compasses. "Compass disconnected" is a hardware error so I ordered up a new compass2 PCB. The two compasses are different and are NOT interchangeable. Compass 1 is at the rear of the top cover and is part of the GPS unit. It is attached to the top cover and it has its own connector to the lower circuit board. Compass2 is on its own very small circuit board at the very front and it is soldered via a 10 cm cable to the main circuit board. There is no connector - it is soldered. All these parts are easily available - on eBay the compass2 costs about $15 from China or $20 from a US vendor and it comes with a (approx) 10 cm cable already attached.

To replace compass2 you have to remove the TOP of your Mavic. This procedure is widely described on YouTube so I will not be redundant. You have to remove about 12 screws and release a couple of clips and disconnect the cable to the GPS/Compass1 card in the top cover. You do NOT have to remove the bottom of the Mavic or the heat sink. See this:


WholeView.jpg
In this image:

Yellow = Compass2 PCB (L) and soldered connection of compass2 cable on main PCB (R). You can see the black cable routing.
Red = Connector for GPS and compass1 module on main PCB. Actual GPS/compass1 PCB located on the top plastic cover in the rear.
Purple = It is helpful to disconnect these four connectors to facilitate compass 2 PCB replacement. The white connectors just pull out gently with tweezers. Put a flat screwdriver blade under the black rectangular ones and they just pop up with a little twist. Youtube videos show this in detail.
Green = Location of 4 phillips screws which should be removed to mobilize large battery power connector.

After you have the top off (careful when disconnecting compass1/GPS cable) , remove the four green screws, disconnect the purple connectors and tape them out of harm's way, and move the wires covering up the soldered compass2 leads on the main PCB. See below - how it looks before you start.

RIMG0225.jpg

Note the white soft glue holding down the soldered leads to the PCB. After you move the wires out of the way, gently remove the white glue using a pair of tweezers being careful not to dislodge the wires. Then unsolder the leads with a fine point soldering iron. The wires are very thin and you must be patient, especially when you are putting the new compass2 board in. Remove the single screw holding the old compass2 PCB in place then work the unsoldered cable out and remove the old compass2 PCB with its cable. Note how the cable is routed through the main battery connector.

The cable on the new compass2 PCB is already stripped and tinned. Install the new compass2 module with the single screw in place of the old PCB. Route the attached cable the same way through the main power connector as the old one. Carefully solder the leads to the main PCB. Green Red White Yellow left to right as shown. When you are done it should look about like this:

RIMG0231.jpg

Replace the green screws on the main power connector and reattach the four purple connectors.

You can now test your repair. Gently attach a battery to the main power connector (with the cover off) and turn it on in the usual way. Start up the remote and DJI Go 4. You will get error messages because you have not connected the GPS/compass1 module. Navigate to Main Controller Settings -> Advanced Settings -> Sensors -> Compass and you should see compass2 functioning and compass1 disconnected (because it is). Turn everything off at this point. Place a small glob of silicone RTV glue over your newly soldered connections and allow a couple of hours for it to start to set. Reconnect the compass1/GPS cable and replace the top cover. All of the top cover screws are identical except for the two holding the small plastic covers in place on each side. These are slightly shorter. Don't mix them up!

Fire up your Mavic and calibrate the compass and you are ready to go.

compass1 and GPS replacement...

I have not had to do this but it should be much easier. No soldering is required. The GPS/compass module is in the top cover and it is widely available for about $40 on eBay. Installed in the cover it looks like this:

RIMG0232.jpg

After you remove the top cover, just take out the old module, put in the new one the same way, reassemble, and you should be ready to go after a compass calibration. I have not personally done this but it should work fine.

Good luck!
 
Last edited:
Always love a nicely detailed tutorial, needs a Mod to add it in somewhere as a sticky maybe @dirkclod
 
Hello i have been having compass 1 disconnect error for a few days now and could not figure it out until i took a good look at the actual part.I found the left end white wire has been pulled out from the connector with the other wires still holding tight.Can i just pop the metal jacket peice out from the connector, open it back up to clamp back onto the white wire and then re click it back into the plug....(sorry i dont have question mark button on my laptop) attempting this is worth a shot to solve the error before buying a whole new part ya no (question mark)
 
Hello i have been having compass 1 disconnect error for a few days now and could not figure it out until i took a good look at the actual part.I found the left end white wire has been pulled out from the connector with the other wires still holding tight.Can i just pop the metal jacket peice out from the connector, open it back up to clamp back onto the white wire and then re click it back into the plug....(sorry i dont have question mark button on my laptop) attempting this is worth a shot to solve the error before buying a whole new part ya no (question mark)

Yes, it is possible. Solder it to the metal connector as it can become brittle if bent multiple times. Or you can replace the connector, it seems to be manufactured by Molex so should be easy to find
 
Awesome information - I am following along with the compass 2 replacement now. I tried and failed to follow your advice to not dislodge the wires when removing the white glue. Unfortunately, I dislodged the green wire (old compass). Can i just unsolder that connection without the rest of the wire there or is this a major setback?
 
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