Tail light out

[wkf94025]

I had a hard crash on one of my P2's last summer. Busted up a few parts: vTx, props, legs, and shell. I finally got around to replacing busted parts, including new shell and legs. Updated firmware, deep IMU calibration, compass calibration, etc. Test flights fine. Only issue is that the right rear "tail light" is out. I get red flashing light, but yellow and green are gone, just on that one leg. The left rear leg works fine, so no problem getting confirmation of P2 modes. I assume fixing tail light means a new ESC? Anyone have any experience with a cheaper faster "tail light" fix than ESC replacement?

Thanks,
Kelly

 

[ksphantom]

Had the same problem once. The LEDs for red yellow and green are separate and in line along the bottom of the esc. Like this [] [] []. They aren't really attached very well. If one breaks off, they all seem to quit working, at least that's how it was on mine. Don't know why you would still get red but not yellow and green, maybe red is on a separate circuit. Suggest opening your shell carefully and see if one of the LEDs is loose or broken off and laying in the little cover. You may be able to reattach with careful soldering - otherwise, only fix is a new esc.

 

[ianwood]

If the lights are out, other more important traces on the board are likely stressed. I would replace the ESC. They're cheap. Challenge is making sure you get the right one as there is a lot of confusion around different versions.

 

[wkf94025]

Thank you both. Agree, Ian, that the missing lights may be a symptom of other issues lurking. Unfortunately I am in Mexico all week, and no chance of an ESC here, so I think I'll try a few test flights over golf course, and see if there is any evidence of bigger problems. If not, we roll the dice. Yes, separate matter is how to get a compatible ESC given the recent changes.

Kelly

 

[Hughie]

Thank you both. Agree, Ian, that the missing lights may be a symptom of other issues lurking. Unfortunately I am in Mexico all week, and no chance of an ESC here, so I think I'll try a few test flights over golf course, and see if there is any evidence of bigger problems. If not, we roll the dice. Yes, separate matter is how to get a compatible ESC given the recent changes.

Kelly

I wish DJI would publish information about backward and forward compatibility of ESCs. We know which ESCs are compatible with which motors, but not which ESC version are compatible with other ESC versions.

Having said that I have flown a P2 Non Vision with 3*v2.0 together with 1*v2.1 with no problems.

 

[wkf94025]

Having said that I have flown a P2 Non Vision with 3*v2.0 together with 1*v2.1 with no problems.

Dang, I was hoping one new ESC would allow me to do loops and rolls...

 

[PhantomFanatic]

Normally LEDs take a long time before they fail. However, I see no reasoning for all of them to go out when only one is defective. (as mentioned before). If you have electronic experience, a meter, solder and a soldering iron, I would dive in and check the LEDs.

If no meter, you could take the good LED and using some jumpers, put the LED in the other outputs.(rotor removed!). If it light up in the other two positions, when that color lights up on the other end arm, then the ESC is good and you will need just two LEDs.

BUT, if no meter and the experience, replace the ESC. Plus, it is highly unlikely that two LEDs would fail at once. They normally last over 100,000 hours. So, I've changed my mind. Above is what I would do, but I think your best approach is to replace the ESC. I assume it comes with LEDs, as I haven't replaced one. You just might have an ESC in its end of life stage.

 

[ksphantom]

Definitely make sure you get a matching version esc as a replacement. I "flew" once with 2 ver. 2.0s and 2 ver 2.1s. It was crazy, constantly weaving side to side wanting to climb up and had to hold the left stick almost all the way down, barely got it down safely. This was all in calm conditions.
Changed the remaining 2.0s to 2.1s and the same machine now flies absolutely perfectly.

 

[Hughie]

Definitely make sure you get a matching version esc as a replacement. I "flew" once with 2 ver. 2.0s and 2 ver 2.1s. It was crazy, constantly weaving side to side wanting to climb up and had to hold the left stick almost all the way down, barely got it down safely. This was all in calm conditions.
Changed the remaining 2.0s to 2.1s and the same machine now flies absolutely perfectly.

No such problems for me in over 4 hours flying with 3 * 2.0s and 1 * 2.1.

Sounds like you had a calibration problem.

 

[Hughie]

Normally LEDs take a long time before they fail. However, I see no reasoning for all of them to go out when only one is defective. (as mentioned before). If you have electronic experience, a meter, solder and a soldering iron, I would dive in and check the LEDs.

If no meter, you could take the good LED and using some jumpers, put the LED in the other outputs.(rotor removed!). If it light up in the other two positions, when that color lights up on the other end arm, then the ESC is good and you will need just two LEDs.

BUT, if no meter and the experience, replace the ESC. Plus, it is highly unlikely that two LEDs would fail at once. They normally last over 100,000 hours. So, I've changed my mind. Above is what I would do, but I think your best approach is to replace the ESC. I assume it comes with LEDs, as I haven't replaced one. You just might have an ESC in its end of life stage.

Yeah good advice. Conventional avionics/electronics fault diagnosis would involve swapping two ESCs over to see if the fault moved.

However there are two good reasons why it might be just as well to replace the ESC.

1. The different LEDs are turned on using different PWM duty cycles. So if any are working at all, and it is not the ESC it is a software problem which is not going to be caused by a crash !

2. The second is that to remove an ESC, whilst not difficult, involves soldering 5 reasonably high current connections. You might not want to do this more than you have to if you suspect it is the ESC anyway. Also remember that there is often a lot of adhesive applied to the main board power connections to the ESC which have to be desoldered and resoldered. You will not get a decent joint on these unless you remove all the solder and then re-tin before resoldering the ESC power cable back on.

Please post the outcome of your repairs back to the thread.

 

[jarance]

The LED at the ESC are dual colour. i.e. RED and GREEN. By changing the intensity of red and green, it will generate Orange (Amber) and yellow.

There are 3 LEDs mounted on each ESC and they are wired in series. If one of the LED is busted, then all the respective colour will not light up.

see below for the circuit.

 

[jarance]

If you want to more detail of the ESC circuit board, check out the thread by RDCF550. He have scan the board and provide a detail wiring schematic of the board.

click link below:-
viewtopic.php?f=5&t=28252