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Aug 15, 2010, 07:08 PM
Registered User
Help!

Su-26xp no throttle problem


Hello, i had a great time with my su-26xp with original brushed motor.
Suddenly i faced that the motor doesn't start anymore, the motor itself is ok - i've checked it by connecting directly to the battery, it goes full power without any problem.
By the way generally the bind process seems to be ok, all other controls beside throttle work fine.
I'm using Dx6i with BNF Su-26xp,

Thanks in advance for your comments.
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Aug 15, 2010, 07:11 PM
Foaming at the mouth..
darksiede's Avatar
If you have a meter, test it between the brick and motor to see if the brick is putting out power to the motor.

Barring that, it could be a throttle problem inside your Dx6i's throttle gimbal.. have any other planes to test it on?

Also triple check that throttle travel in the programming of the Dx6i can go to 100%, and check throttle trim as well.

~Kev
Aug 15, 2010, 07:40 PM
Registered User
Quote:
Originally Posted by darksiede
If you have a meter, test it between the brick and motor to see if the brick is putting out power to the motor.

Barring that, it could be a throttle problem inside your Dx6i's throttle gimbal.. have any other planes to test it on?

Also triple check that throttle travel in the programming of the Dx6i can go to 100%, and check throttle trim as well.

~Kev
1) Tested my dx6i just now on another su26xp and t34 mentor - works fine.
2) unplugged the motor, binded the su26xp with the transmiter, checked voltage on the (+) and (-) - no voltage. But there is voltage between the very left pin (the for for brushless ESC) and both (-) and (+).

Any ideas?
Aug 15, 2010, 08:08 PM
Way to many airplanes!
There's a procedure to switch the motor ouput from brushed to brushless. It would be amazing if you did it by accident, but who knows, everything is possible. If you did accidentally switch it to brushless, then sure enough, the brushed motor would not do anything.

Check the user guide for the AR6400 board, on the Spektrum website or included with your plane. Follow the steps to switch back to brushed.

Otherwise, who knows, maybe the ouput is simply fried. Would be a first though.
Aug 15, 2010, 08:28 PM
Foaming at the mouth..
darksiede's Avatar
Quote:
Originally Posted by Bluemzd
1) Tested my dx6i just now on another su26xp and t34 mentor - works fine.
2) unplugged the motor, binded the su26xp with the transmiter, checked voltage on the (+) and (-) - no voltage. But there is voltage between the very left pin (the for for brushless ESC) and both (-) and (+).

Any ideas?
Yeh, like RG says above, it sounds like you got switched into PPM mode for brushless on accident.

Easiest way to unswitch, is plug a battery in to the plane, then push your left stick full up, and full left, and power on the Tx..

The brick will flash, then unplug the battery, replug and try your throttle.

~Kev
Aug 16, 2010, 05:30 AM
Registered User
I have tried that before posting the thread, - after changing the mode, the motor start on maximum power and became uncontrolled.

Can any one try to change the mode from brushed to brushless on a working parkzone micro plane - to see how does the motor works under such conditions.

Thanks in advance
Aug 16, 2010, 05:50 AM
Way to many airplanes!
Can't check right now, but that's quite interesting!!!

In brushed mode, the center pin is always positive. I think there's no control at all on that pin. I think they control the other pin which is the negative so the motor go up and down in speed.

In brushless mode, again, the center pin is always positive. And now the same pin is used for the PPM, so it's a digital signal. So when you switch to brushless, it would be normal for the motor to spin. Still positive on one side, and getting pulses on the negative side. I would not say top speed, but likely fast.

So if I'm right, this would mean that you have control when you switch to brushless, but somehow, in the controlling part of the brushed motor (maybe different FETs?), something is wrong.

A cheap solution would then be to simply buy a brushed ESC!!! Some people have done that here, simply because with an external brushed ESC, you get a different HLVC and SLVC. I think Maukabud is the one who like this solution the most, so I would send him a message about this.

A AR6400 board cost a lot. Sure enough, if your's is under warranty, send it away, but if it's not, a brushed ESC for such a small motor would not cost much and likely allow you to still use the board.

Sure enough, I will try to do the switching myself tonight to see if I get the same result (which I'm pretty sure I will).
Aug 16, 2010, 07:44 AM
Foaming at the mouth..
darksiede's Avatar
rebind with your throttle at 0%, should solve the problem!

~Kev
Aug 17, 2010, 08:50 AM
Registered User
2 darksiede: Binded with throttle at 0% - no resuls.

I have bought a conversion Kit with brushless motor and brushless ESC, Changed mode to brushless. But still no result - no throttle, all the other functions work great.

Any ideas?
Nov 17, 2012, 08:27 AM
Registered User
Hi Bluemzd

I know this is an old post, but since I'm facing the exact same problem with the same plane, I was wondering whether you ever were able to resolve this problem?
Nov 18, 2012, 04:31 PM
Registered User
I experienced the same thing, checked my batteries and the voltage was ok. Had the same problem with my msr heli, no motor startup. I read somewhere on this site that the lipoly batteries can go bad even though the voltage looks ok so I tried some brand new batteries and everything worked! So maybe your batteries have gone bad
Nov 19, 2012, 03:33 PM
Registered User
So everything worked except throttle only because of the batteries?

I tried all batteries I have, nothing changes. And of course the motor is running when changing to brushless mode.
Nov 24, 2012, 07:41 AM
I live on LiPos
RcAirplaneNoob's Avatar
I had the same issue with my polecat and it turned out I had the throttle trimmed out on my dx6i. hit the bottom(or top i forget which one) button that goes vertical to the right of your throttle stick (assuming you use mode 2) and see if it works. it did for me.
Nov 27, 2012, 04:49 PM
Registered User
I tried that and set the throttle trim all the way down, no change, unfortunately.
Jan 27, 2013, 10:29 AM
Registered User
I have a similar problem with my sukhoi. I lose connection with the plane after about 75 feet away. I think it's a batter problem. Any suggestions?


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