Bought a busted up P3P - need some advice

[flightjunkie]

I stumbled across a deal I couldn't pass up. Part of the package was a P3 Professional that is pretty beat up. I bought the stuff mainly for the 7 factory dji batteries that came with it, but I figure this P3P could be a cool project.

I'm hoping you guys can help me determine if it is worth fixing or not.

-Camera and gimbal seem fine. It all moves freely, RC angle control works, video transmits to controller/tablet.
-Obviously the case is busted (~$60) will need that right away.
-Obviously will need at least one motor right away (~$20) I would replace the remaining 3 immediately if the first test went well (meaning no ESC issues).
-RC is holding charge and seems to work fine (sticks move freely and it connects up with no problems)
-Both RC and Aircraft need updates (working on that now)

-IMU abnormal, this is flashing from normal to abnormal back and forth quickly while watching the aircraft status on the GO app. This is the most concerning thing to me. I can understand needing calibrated, but the way it is flashing back and forth from normal to abnormal concerns me. My biggest concern with this project is having to replace the ESC if necessary, what do you guys think?

Do you think this is worth trying to fix?

Is there any feasible way to fully test the ESC prior to replacing the case and motor? If not, do you think this will likely need a new ESC or is it too early to tell?

What are some other things I should be checking? (aside from tearing it apart, which I'll do tomorrow)

Any and all help, advice, or information is greatly appreciated.
Thanks in advance!

 

[With The Birds]

You could use a DMM to crudely test the power Mosfets on the ESC outputs.

You may have a stuck IMU. A gentle tap may free it up. Can you see the IMU vakues in the sensor screen of GO?

 

[flightjunkie]

I was able to see the IMU values in the sensor screen earlier. I was going to take a picture to post up, but since I did the update on the RC, I haven't been able to connect back to the aircraft.

So I tried doing the firmware update on the aircraft, it seemed to go through the install process several times very quickly (it was strange) so finally I shut it back off, plugged in usb, turned back on and checked the SD card. It had the text file, showing success, but about 7 times instead of just once.

So I tried to connect to RC again (which it wouldn't), and now the lights on the aircraft are all off and it is making a very loud constant piercing beeping after the last power off/on. I'll have to do some more research and troubleshooting.

In the meantime I will try and do the firmware update on the aircraft again since that one didn't seem to go normally.

 

[flightjunkie]

I tried the firmware update again, same thing this time except the loud constant obnoxious beep (I can hear the regular "updating" beeps still, but under the sound of these beeps). Here is what the text file looks like (after being on for about 2 minutes with the updated firmware on the sd card).

 

[flightjunkie]

After more searching and research I think I got the firmware to update. The constant beeping is gone, it is now just the D-D----D D----D D----

I had to re-link the RC, but got it connected again.

Aircraft status screen still shows overall status as "abnormal" (see photo). When I click it, the message "accelerometer failed" appears (see photo). The IMU status is still changing from normal to abnormal, so I took a picture of sensor state before and during calibration (see photos), but the calibration process is currently stuck at 28% (going on 25 minutes right now of being stuck).

Am I wrong in thinking that the ESC will likely need replaced in this unit? Do you guys think it is worth fixing?

I appreciate any and all information or advice,
Thank you.

 

[With The Birds]

Give the IMU a committed but mildly cautious tap on the top right (looking from the front of the main board) with the handle of a screwdriver and see how the IMU vakues look. Stuck IMU is the likely culprit here. ESC is a secondary issue potentially. Do you have a multimeter? The common mosfet failure modes are easy to detect with the ohm metre and diode test functions.

 

[flightjunkie]

I do have an ohm meter, but am no professional at using it.
When I get to that point, I will post back with a picture of my meter and the ESC board in hopes for some guidance.

For now I will give it a good tap on the top right, check values, possibly try IMU calibration again, and report back.

Thanks 'With The Birds' I appreciate your knowledge.

 

[flightjunkie]

I gave it a solid tap and the values didn't change. I tried IMU calibration again and it froze up at 2% this time.

Here are some more pictures. I don't see any visual damage to the ESC, just dirty. Is it ok to use keyboard cleaner (compressed spray) to clean it up?
GPS chip doesn't look cracked or damaged.

I've attached a picture of the multi-meter I have, would this work for the testing I need to do?


EDIT: I took the IMU out of its plastic case and gave it a few taps, re-installed and IMU calibration went smooth. There are no more errors on the flight screen or aircraft status screen. My flight screen says "Ready to GO (Vision)" so I assume I might get away without replacing ESC.

I'm ordering a case and a motor for now, will go from there. Anything else I should be replacing while I'm doing this? Any suggestions where to buy the parts? DJI website shows no stock for the shell so I plan to purchase a used one on amazon (so at least I know it's genuine dji, and it will come with the LED covers which seem hard to find). Where can I purchase genuine dji motors? I'm not finding them on dji's website.

Thanks for the help!

 

[flightjunkie]

Well I got this thing fixed up and took it out for its first flight (or flight with me anyways) and it did great.
The camera horizontal position is not perfect, but its not far off and I haven't attempted to fix it yet (doesn't seem like it will be a big problem).

Overall I replaced the shell, one motor, the props, and the gimbal pins & rubber holders. I'm very pleased I decided to take on this project! I ended up with this thing for free with a package deal, and fixed it for less than $100.
Thanks for the help 'With The Birds' I appreciate it!

 

[Richard R]

Sounds like you lucked into a pretty sweet deal and "With the Birds" certainly gave you some great guidance. The only thing I would add for anyone else who might have occasion to try something similar is to not do any FW updating at first! It's reasonable to expect the everything was linked up and communicating properly before any crash. Once you start monkeying with the FW, you'll never know what the cause is if/when things start going south! I would always recommend that any hardware mechanical issues be attacked first. The. Once you have a properly functioning bird, then you can consider if any FW updates are needed or even wanted. Happy flying!

 

[flightjunkie]

Sounds like you lucked into a pretty sweet deal and "With the Birds" certainly gave you some great guidance. The only thing I would add for anyone else who might have occasion to try something similar is to not do any FW updating at first! It's reasonable to expect the everything was linked up and communicating properly before any crash. Once you start monkeying with the FW, you'll never know what the cause is if/when things start going south! I would always recommend that any hardware mechanical issues be attacked first. The. Once you have a properly functioning bird, then you can consider if any FW updates are needed or even wanted. Happy flying!

Good advice! I wish I had done that, because updating FW when I did (before repairs) just complicated things.