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Old Sep 18, 2012, 05:57 AM
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Hmm...first flight..first crash..DJI F550

Well finally got my dji f550 built and had the first flight today, took off in alt mode then switched to GPS mode, everything was going well maintained a steady hover, controllability checks were good everything seemed to work. Then I decided to fly it away to right by around 40m (whilst still in GPS mode) on the way I noticed the a/c twitch down every so often but didn't take to much notice. Then I switched the tx off to test fail safe, the a/c climbed to 20m as it should then tried to come home however it started to twitch even more and corrected itself each time. I then thought something's not right and decided it was time to turn the tx back on to land when I observed one motor stop and the hexa came crashing down. One arm broken and a dented lipo. The motor on the broken arm tested fine however number 1 motor doesn't work. Tried it on several esc's but still no go.
I'm putting this crash down to a faulty motor. What are the chances of dji replacing the broken components including the faulty motor?
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Old Sep 18, 2012, 06:18 AM
Mmmmmmm!
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Hard to tell, talk to the person/company you bought it from. Warranty should cover that.

As for the twitches, several others have experienced that, myself included. You most likely have a badly soldered bullet connector on that motor. Remove the heat shrink on the plugs, tug hard on them, one wire will most likely pop right out of the connector. Re-solder it, check all other plugs. My motors all work fine now after my last inspection.
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Old Sep 18, 2012, 06:43 AM
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Thanks,

Just checked the bullet connectors and they were fine, even ran a multimeter across the leads and continuity was ok. I'm at a loss as to what has happened other than my speculated bad motor. Just purchased all the replacements parts required and will see if dji will replace the other under warranty. Good to have a few spares.
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Old Oct 06, 2012, 05:45 PM
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A motor stopped again during fail safe..bloody hell!

Put all the new parts on the hex and conducted my first test flight, just a hover. The hex has a really bad twitch so after reading the posts here I decided to re solder my bullet connectors which made a big difference, the twitch is still present but at least now the hex is controllable.
Second flight was at the park where I decided to test the fail safe come home and land function. The hex did all the right things, climbed to 20m, flew to the take off point then hovered before starting the descent. It was at this point when the hex started to twitch really bad again, I thought it might had been the upwash from the props during the descent so didn't take controll. It twitched twice really badly then finally the motor stopped and the hex came crashing down. The motor that stopped was really hot and is on a different arm to the last motor that stopped. What is the problem? Shorly I couldn't have two faulty motors, although the soldering of the bullets connectors leads me to believe its possible.

Again I have another broken arm and faulty motor to replace. This is becoming very annoying, by the time I have finished spending money fixing this over and over I could have purchased a MK.

Does anyone have suggestions as to what might be causing this?.
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Old Oct 07, 2012, 07:43 PM
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I've just ordered more motors and bullet connectors, I plan to replace every connector with new ones and try again. Not sure if this is the right approach as I'm at a loss to what's causing this, I hope it's not a dodgy naza flight controller?
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Old Oct 08, 2012, 12:33 AM
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Old Oct 08, 2012, 01:05 AM
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If you are having any issues then you need to test on the bench as attempting to fly will end in tears and the problem will not fix itself.

If the re-solder made this better then may still a bad connection?
On the bench tied down you can at least carefully move wires and see if the problem can found without crashing.

I think I read in a forum people have issue with some type of hex when switched to GPS and it crashing, may not be the same and I cannot find the thread
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Old Oct 08, 2012, 08:37 AM
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Thanks for the reply, I might actually do that when the new motors turn up. I plan to place brand new bullet connectors on all the motors using my own solder and flux. Hopefully this might fix the problem. I really am at a loss what else might cause this
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Old Oct 16, 2012, 06:26 PM
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Well I have replaced 3 failed motors all from the original ARF kit, 1 ESC, 3 replacement arms, 1 top plate and every bullet connector for every motor including the replacements (all replacement parts were at my own expense) and I finely have a flying machine, I have had 8 flights with no twitches or failures. I can't believe how poor the quality control is at DJI, to have so many parts fail from the same kit is ridiculous. My next multirotor will definately not be from DJI this has left a bad taste in my mouth. Even after 8 successful flights I'm still not confident in mounting my gopro yet. - still can't believe my luck
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Old Oct 19, 2012, 11:00 AM
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Hi All, just gone trough this thread and could not believe what I've read.

I just build my F550 with the exact same issue.

At this point, I have replace 3 motors and still found another faulty today. I've not gone trough the process of re-solder'ing, but it seams I have to.

While replacing the motors, I found that the DJI logo is silver where in the original version it is gold. Jdmagoo did you also notice the difference in the motor-logo?

For now, the replacement motors seem to work.
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Old Oct 19, 2012, 06:14 PM
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Interesting....

I spoke with my builder earlier today and he said the 1.8 update for the NAZA was causing a bunch of problems and that he was looking for a way to go back to 1.6

BTW, what Rx/Tx are you using?

My RTH is programmed to a switch and it works fine, but I don't like the position because I already flicked it by mistake, causing me to crash into a tree

And from what I've gathered from others here, my Rx doesn't have a programmable fail safe, so a signal loss from turning off my Tx may cause it to crash rather than RTH

As for mounting your GoPro, I wouldn't worry about it

I've had mine in some pretty hairy crashes on land that simply falling out of the sky would be nothing more than a bump in the road lol
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Old Oct 19, 2012, 06:38 PM
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Quote:
Originally Posted by ninja_fighter View Post

While replacing the motors, I found that the DJI logo is silver where in the original version it is gold. Jdmagoo did you also notice the difference in the motor logo?.
G'day mate,

The logo on the original and replacement motors is red. Haven't had one that is silver or gold before, unless I'm missing something.

Putting new bullet connectors on the other motors definetly made a difference and strongly recommend it.
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Old Oct 20, 2012, 04:39 AM
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Quote:
Originally Posted by 98 SNAKE EATER View Post
Interesting....

I spoke with my builder earlier today and he said the 1.8 update for the NAZA was causing a bunch of problems and that he was looking for a way to go back to 1.6

BTW, what Rx/Tx are you using?

My RTH is programmed to a switch and it works fine, but I don't like the position because I already flicked it by mistake, causing me to crash into a tree

And from what I've gathered from others here, my Rx doesn't have a programmable fail safe, so a signal loss from turning off my Tx may cause it to crash rather than RTH

As for mounting your GoPro, I wouldn't worry about it

I've had mine in some pretty hairy crashes on land that simply falling out of the sky would be nothing more than a bump in the road lol
Thanks for your feedback,
I use a Graupner mc-20 which is rock solid when it comes to transmission. It also measures the data loss and error-correction on the channels it's using. So no issues there..

However, the apect of firmware.. Hmm. I've also seen some posts which points into that direction, but then the soldering would have no affect.. Lets find out.
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Old Oct 20, 2012, 04:49 AM
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Originally Posted by Jdmagoo View Post
G'day mate,

The logo on the original and replacement motors is red. Haven't had one that is silver or gold before, unless I'm missing something.

Putting new bullet connectors on the other motors definetly made a difference and strongly recommend it.
sorry, I was confused with the colors, original is red not gold, but my replacements are silver..

Yesterday I almost crash it on twitching motor 5. I decided to re'solder just this motor to see if this make a difference. It is still from the old series (red label)

I'm also not feeling comfortable even the problems would finally be gone. I've read from issues that show up after some flights and I do carry my camara and FPV gear. I might go for a full replacement of all motors with e.g. AVROTO. On top of the described problems I got lots of vibrations which makes my recorded video unusable..
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Old Oct 20, 2012, 08:47 AM
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okey, here are the results, and the story continues..

1. re-soldering didn't do the trick. Same twitches again with the same re-soldered motor. I've replace this motor with one I had re-soldered as well. problem was gone, at least I was able to do a 3min flight without any twitches.

conclusion 1: sometimes motors, sometimes just the bullet-connectors are the issue.

2. I did another test-flight for 3-min. everything looked great. But, and you can imagine what happens; crash again! this time a prop was breaking of just by hovering about 1m of the ground.
I don't have to tell you that I'm checking all parts before I lift of. As a result I decided now to switch all props to the graupner. While chaning I found that on some of the motors, the motor shaft seems a bit different. in two cases I was unable to screw tight the graupner props...argh.. I'm now so frustrated and close to throw this thing into the trash.

...now I'm going for another testflight with the graupners.. I'm sure something else will fail..
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