Arming the APM 2.5

I have a problem that I cannot seem to resolve.  I am unable to arm my quad so that I can fly.


My set up...

A 3D robotics quad

APM 2.5

Firmware 3.0.1

Spectrum DX7s Transmitter

AR8000 receiver with telemetry installed.

Mission Planner 1.2.70



The APM will not arm.  After APM boots I wait for GPS lock (LED solid blue)  I hold the throttle at low and to the right.  The RED LED changes from flashing red to solid red momentarily then goes dark.


Troubleshooting that I have done and attempts to correct.

1- Clean install of the firmware on the APM.

2- Calibrated radio multiple times.

3- Calibrated ESC's procedure works well

4- Trims on controller have no offset and the "rudder" is set correctly.

5- Tried a new clean model on the TX and rebound the Receiver. (repeated above)


I have run out of options and really need some guidance.

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  • Mine wouldn't arm.  When I did the Tx/RC calibration I noticed the two sticks were coupled...must have had a mix enabled for a different airplane.  Switched to a different model, recalibrated the RC/Tx and it's arming now.

  • The "Pre-Arm checks" video helped me know where to go to figure out the ARMING and DISARMING sequences.  Until then, I'd been flailing away.  Now I know both sticks down and in arms, and down and out disarms.  Also not knowing what the LEDs meant was probably an issue.  Now I know solid blue is GPS lock, slow blinking red is ready but DISARMED, and solid red is ARMED. 

    I still don't know what all the stuff is in the Flight Data screen, and obviously searching for it on the APM Planner 2.0 site is useless.  I tried that -- NOT FOUND... NOT FOUND... NOT FOUND... Geez this hobby is FLAKY!  At least now I know how we managed to crater a spacecraft on Mars.  They were using "documentation" like this.  :)  In the I.T. industry we literally fired people on the spot for BETTER documentation than this.

    Thanks to this site and a couple of others, this can get sorted out, given enough time.  Is there a team working on actually documenting any of this stuff?  I'd gladly volunteer some time to write or edit.  The quadcopter hobby is taking off, no pun intended, but it'll be slowed considerably if it continues to be a Gordian enigma.  There are people with money and the desire to do this who don't share our fetish for sleuthing out what should just be a click away.  If we want that money to grow this industry, it might be a good idea to court it.

    • I agree.   It is incredibly difficult to find small bits of information.  The data is so fragmented and posted and responded to in troubleshooting posts like mine.   

      For example, I had to disassemble my quad to make a small modification to a frame plate.  When I was re assembling it I couldn't remember how my ESC should be plugged in to my PDB.   So I went to the assembly instructions to determine the proper way.   There is not one tidbit of information anywhere to be found.  I then started hunting for some photos of other quads to see if I could get a hint from an image.  No clear images anywhere.  I ended up just making a guess and risking that I would fry my ESC.  Fortunately, I did it correctly.  :)

      I also am in the I.T. industry and this is one of the big reasons OpenSource gets a bad rep from Fortune 500 companies, poor documentation.   I enjoy challenges but wasting time is not part of the challenge.

  • Did you ever solve your issue?  I have the exact same setup and same problem.  After erasing and re-doing all the setup it still wouldn't work, then by luck I put the transmitter F MODE (no idea what this is for) switch to 1 and then held throttle to the left vs right, it armed.  It won't arm without F mode on 1.  Obviously my controls are reversed and I still haven't figured out how to correct them, which is what I am trying to do now.  If anyone knows or has a pre-configured config, i'd really like some help.

  • i think john is getting to the point of using the power module and bec power,,,,you dont want to do this ,, if you use power module you have to cut red wire on bec`s,,,i could be wrong though

  • Watch this:
    Pre-Arm checks.
    If that doesn't help, read this:
    Maybe read it anyway.
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