Hello all,

I built a hexacopter and did wanted to check the motors, so in the terminal I ran:

# setup

# motor

(If I remember right)

I am talking about the test function who increase the PWM signals on the outputs, channel by channel.

The problem is:

Only one motor is working. on channel 3 (motor 3).

I switched motor 1 with motor 3, I mean, channel 1 -> motor 3, channel 3 -> motor 1

ran the setup again and this time only motor 3 is working...

First I thought the problem raises on the connection or ESC's  so I connected all of the ESC's one by one directly to channel 3 on the receiver and with a little throttle I checked all of them and they all worked.

So what else it can be?

Thank you very much!!!

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Hi Nati- Ive seen that problem more than once, and never got a satisfactory answer here. From what i could tell it boiled down to a few things:

1. check all of your bullet's solder joints. You can test across the joint with a resistance test to help determine the quality of the solder joint. Also check resistance from the PDB to your end points, as you could have a cold joint at the PDB to the dean's connectors. If you are in doubt of all of this, simply solder all of your connections wire to wire. Its not a totally oneway trip as you can desolder when and if you need to. Id say this would be a last resort though. Make sure also all of your solder joints are shiny too. This doesnt guarantee that you have a solid connection, but if the solder is dull, it usually means that the joint was moved as it was cooling and is more likely to be problematic.

2. Make 100% sure you have the ESCs calibrated. I dunno why it would be, but were i to guess, if the bottom point is too high on the calibration, the signal from the APM during testing from CLI may not be sufficient to spin the motor. Bear in mind that this is a total guess, but sometimes correlation does equal causation. Also i have NEVER had luck with all-at-once calibration. NEVER. EVER. I use caps, because that alone has caused more hairloss than women and taxes combined. Calibrate them seperately and youll be better off. SOme other pilots here have switched to ESCs with external clocks and one guy in particular said he hadnt had to calibrate in over a year. id recommend doing this before all the resoldering.


3. Also, if you are using the yellow stock ESCs, you may want to flash them with the SimonK firmware as you will have a much more responsive throttle if you do. Plus, there's some other behaviours programmed in that really only apply to fixed wing aircraft. Its a PIA, but worth the effort if youre gonna do this hobby long term.

4. In the end, i did end up having a screwy APM, which DIYDrones agreed to swap out for a new one. Im not saying that is the issue, but it's possible.

good luck, let me know what ya find


P.S. I may be totally wrong on some of this, Im not an expert, but i can sure break stuff!

Test each motor subsection with your RC RX first (connected to the Throttle output of the RX -- TAKE OFF THE PROPS!)

When each ESC/Motor combination works, then reconnect all wiring to the APM for Hexa setup.

Try 'motors' command again.

Somewhere in this process, if you have a wiring error, you will find the solution.

Of course you must have Hexa loaded in Mission Planner. We have seen more than one new build have the wrong code loaded. It would be embarrasing to find you loaded Arduplane rather than Arducopter... ;)


Thank you very very much!

I already did this test and all the motors / ESC's seems to be working fine..

Thank you again :-)

Thank you very much !!!

Well, I'm starting to believe there is a problem int the ESC's calibration ...

Or something bigger then that, I am getting it wrong the meaning of calibration.

When you say calibration do you mean to the settings of the ESC (Like what the kind of battery used, cut-of, etc..)?

Where and how I configure the minimum throttle the ESC's can start from? (Maybe this is called calibration? )

I wrote my own function to test the motors, I added  200 PWM's signals to all the output channels, for now I have only tow ESC's and they are working... 

Wonderful! The RX---ESC---Motor tests confirm that there is nothing wrong with those sections of your project.

Now the possibilities are reduced!

Is your Hexa a 3DR?

If not, what PDB  are you using? The 3DR PDB also distributes the motor ESC signals.



No. My Hexa is not a 3DR but my PDB is.

Well. I tried to connect the ESC's directly to the APM but still with the dame results... :)

Can you please explain to me how can I let the APM know what are the minimum PWM signal of my ESC's?

Thank you !!!

The relationship between your RX Throttle output and the APM throttle input is established with the calibration procedure.

Use Mission Planner and follow the steps HERE.

What ESCs are you using? Some ESCs have issues with APM. This is what Bart was mentioning in his previous post.

Direct connection of the ESCs to the APM is fine and should work (assuming correct firmware/code is loaded).

Do you know how to capture a log file and post it?


Thank you.

So I already did the calibration...

Unfortunately I am using those cheap Turnigy AE-30A Brushless ESC and currently only tow of them are working...

Can you please explain how to capture those logs files? 

BTW. I burn some of the ESC so I have only tow for now... :-(

Thank you VERY much !!!

You are welcome.

Datalogging and accessing the logs is discussed HERE.

Another feature that will help you analyze your software (if it needs it) is to turn on the 'motors' command in the CLI. This will add the drive value of each motor to the logging. Default is no 'motors' and only the input throttle read by the APM and the output throttle sent by the APM are shown in the logs.

It is odd that you seem to have killed two of your ESCs.

You are not the first to have problems starting up. I too have problems. This is how you learn the way the system works.

I recommend you read over THIS blog post. There is much informaton regarding getting you aircraft running, using logs, using CLI, and more.



Thank you very much !!!

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