I've a strange problem with xracer F3 v3. Motor 3 does nothing when I throttle up (without props) on my new build. But I can spin it up with no problems in blheli. So i guess ESC is working and FC pins, too?

Or is it like a new feature of Betaflight 3 that it won't spin without props?

Do you have a custom mixer configured in the cli?

No, I don't even know how to..

What kind of looptime are you running, multishot/oneshot? What escs?

Aikon ESCs, blheli 16.2, currently oneshot125, 2k/8k..all stock. Only motor 3 won't spin, others are fine.

These are blheliS right? I think you can try to run multishot, but I'm not sure if it will fix your problem. Are you running 8k on oneshot125? If so, I think that could be a problem. The gyro update can be 8k, but the pid loop needs to be 4k or less if you run synced oneshot125. I even had some problems with littlebee 20a and oneshot 125 on 4k, where one of the motors just stalled and went to half throttle when doing a punch out. That is why I would try to either lower the pid looptime, or try multishot

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I might have misunderstood you with 2k/8k. Does it mean you run gyro update on 8k and pid loop on 2k or opposite? The opposite I don't even think is possible, but just making sure

appreciate your help oyvinla

It is pid loop 2k and gyro 8k. I think I'm changing to multishot and 8k/8k and do some further tests. I'll report back then.

Put esc 2 on FC esc pin 3 and see what happens. I had a F303, where motor 1 2 and 4 worked fine, 3 did not at all, but did run up in blheli.

I swapped 2 esc's over on the FC and whichever motor was on the FC's number 3 channel failed to work with the others.

Reflashed the board and still the same, just figured the FC did not want to work anymore, tried another F303 and all worked fine.

What I am saying is, do not rule out the FC as being the cause.

Sure, no problem! Hope that will solve your problem

(16-Aug-2016, 09:49 AM)BigglesFPV Wrote: Put esc 2 on FC esc pin 3 and see what happens. I had a F303, where motor 1 2 and 4 worked fine, 3 did not at all, but did run up in blheli.

I swapped 2 esc's over on the FC and whichever motor was on the FC's number 3 channel failed to work with the others.

Reflashed the board and still the same, just figured the FC did not want to work anymore, tried another F303 and all worked fine.

What I am saying is, do not rule out the FC as being the cause.

Was it a x-Racer? Which version? Is there a way to overcome this problem? Maybe remap motor output 3 to pin 5? I will try your suggestion with swapping esc 3 over to 2.

I have not remapped to pin 5 before, but it could be that the custom motor mixer can do that. You can remap 1 2 3 and 4, so I guess you could try

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This is the mixer that are used for a X type quad:

mixer custom
mmix reset
mmix 0 1 -1 1 -1
mmix 1 1 -1 -1 1
mmix 2 1 1 1 1
mmix 3 1 1 -1 -1


If you change it to this, I believe you will change esc output 3 to 5 

mixer custom
mmix reset
mmix 0 1 -1 1 -1
mmix 1 1 -1 -1 1
mmix 4 1 1 1 1
mmix 3 1 1 -1 -1

Paste it in the CLI and hit enter. then Write save and hit enter again.

This is based on this calculator:
https://www.iforce2d.net/mixercalc/

Here is also something about remapping the motors:



If you do this, please make sure you test it at the bench without props! I have no idea what is going to happen if you do this change, but I assume it will work!

I have also experience motor output 3 failing on my Naze32 rev5 recently, first it stopped working occasionally, recovering after a power-cycle, but now it's completely gone.

Still no idea about the reason of failure. I was testing my BLHeli Configurator extensively, although not specifically on Motor 3 but on all of them.
Solved by shifting outputs 3, 4 to 4, 5. Not very convenient as output 5 overlaps with standoff on my F1-5 :-)