Post-crash Assistance - Phantom 3 Standard - Sporadic Flying

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Good day,

I've crashed the drone a couple times but up until now the only casualty was a broken prop, easily fixed. I bought it used as well so there may be previous crash history I'm unaware of. This latest crash came down through an evergreen tree and landed on a roof, relatively softly compared to other crashes (low battery put it into Go Home Mode, spotty connection and my lack of foresight couldn't stop it in time before it hit the tree). Unfortunately this latest crash created two unwanted issues:

1.The camera gimbal arm now does the crazy dance. I've done the quick fix I found elsewhere on this forum where you just l open up the arm and level that central gear. It worked great for one flight but now has begun doing that again. I've reviewed the instructions on doing a full replacement of the gimbal and I think I can manage that. Open to suggestions if somebody has other ideas though!

2. Sporadic flying (see video). The drone had two broken propellers so I replaced all 4 with some props off Amazon - no idea if they're any good but I can't see them creating the flying problem (XCSOURCE RC042 9450 Self-locking Props CW CCW for DJI Phantom 1 2 3 Vision, 4 Pairs, Toys & Games - Amazon Canada). The app doesn't appear to show any errors, I've re-calibrated the IMU and the gimbal arm, and I've visually inspected the rotors/vacuumed them in case any debris got in. They don't make any unusual sounds and from what I remember, they feel like they always have. My initial guess is that I've partly burned out a rotor or two? There are some cell deviations in the logs but I thought they'd be permanent. Open to any and all suggestions. I've attached the flight logs from the flight and the first flight after the incident. Happy to provide whatever else might help.

Much appreciated.

I'm unable to upload the post-crash flying video so here's a Gdrive link:
 

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Ok i can clearly hear some squealing from the motor bearings. I'm sure if you rotate all 4 props by hand you will feel a distinct difference on at least one motor on how freely it moves. Definitely sounds like a bad motor but it could also be other electrical issues.
 
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I agree. It sounds like one motor has a problem to rotate normally.
If you can locate which one then replace it. And check blades if all of them are attached firmly.
 
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Ok i can clearly hear some squealing from the motor bearings. I'm sure if you rotate all 4 props by hand you will feel a distinct difference on at least one motor on how freely it moves. Definitely sounds like a bad motor but it could also be other electrical issues.


I've rotated them all by hand and they all feel like they always have but I definitely hear the noise you refer to. If it's one of the motor bearings shouldn't I see something in the flight logs for a particular cell?
 
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I agree. It sounds like one motor has a problem to rotate normally.
If you can locate which one then replace it. And check blades if all of them are attached firmly.


Thanks for the reply. I'm inclined to agree, I just can't figure out which one(s). They all feel the same to me and I take the props off after each flight so that shouldn't be an underlying cause. Is there a diagnostics, or calibration, or somewhere on the flights logs I can use to see which ones are underperforming?
 
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If you arent getting any error messages on screen during flight then its unlikely the flight logs will show anything either. You can do a motor start with props off and listen more closely to find the suspect motor.
 
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Yes, turn the motors on, no props. Get a small screwdriver and put the blade against each motor in turn and the other end pressed to your ear. Any motor noise will transmit to you ear so you should be able to identify any problem.

Make sure you push the ear closed with the end of the screwdriver, that way you are effectively transmitting the sound directly to the ear drum.
IMG_7716.jpg
 
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Thanks for the help so far. May have been just my ineptitude, but when I tried to run the motors without blades, they spun quickly for a second then wouldn't try again. I opened up the housing to see if I could see any obvious signs of damage on the motors themselves. One makes an audible clicking noise as I manually turn it but I was thinking I might just replace all 4 for simplicity sake. In the pictures attached it looks like there are a couple corroded spots.. is there anything else obviously wrong with the board? I'd hate to replace the motors just to have the issue end up being ESC related or something similar. Also, does anybody have a link for these particular motors? It appears there are many different kinds out there and apparently lots of fakes, even if you do find the right ones.
 

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IMG_20200925_134941.jpg Possibly a bit of overheating on the RH connections.
Motors shouldn't "click", they should be smooth and silent.
IF you are going to change out the motors make sure of your SOLDERED joints.
Make sure you get the right motors - those look like 2312A.
As long as the joints onto the PCB are solid, not gone "dry" (possible problem where there is evidence of overheating), you can just cut the wires off midway between the PCB and the motors (saves trying to remove the glue), and then remove a short length of the insulation, SCRAPE THE VARNISH OFF the copper wires. Before twisting/soldering slide a length of heat-shrink tube along one of the wires and then once soldered slide it over the joint to insulate it.
Twist the ends tightly together and then SOLDER them - slide heat shrink over the joint.
If you're going to completely remove the old wires then you'll need to remove the glue from the joints first and then unsolder each of the three THICK wires making note of which colour goes where (you've got the photos so no problem there) and then re solder the new motors in making good clean joints. Try not to overheat the PCB.
 

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