Wkm led

saidquad

Member
I have two WKM flight controllers. One of them is set up to my Xaircraft 650 V and the other to DJI S800. Both aircrafts are controlled by the same radio (JR 11 DSMX) and both of them have almost the same FC setup. The one which is attached to x650 V is working properly with no issues, but the one which is attached to S800 has a problem. When I connect the battery to the system, the LED starts to blink red, green, blue, white and then goes off. No LED indicator in any of flight modes. When I switch one flight mode to the other I see the result change in WKM software, but no indication is given by the LED. Also if there is no GPS connection the LED does not blink red. When the home point is set the LED Does not flash green. Simply said, the LED just flashes when plugging the battery and does not work after that at all. Please help.
 

I had a similar problem with my LED on my S800. I was getting the colors on startup but then all I got was double sparks of white no matter what I did. I replaced the LED with one from a different copter and it works fine now. Maybe try the LED from your 650 and see if it works.
 

Bella7821

Member
I had problems with my LED also. I think it's too delicate and if pressed too hard an LED will go out.
I could press lightly on the bubble and make the LED change color. Then could also flick it and make the LED show the incorrect color.
If you gently push it you will see what I mean.
 

saidquad

Member
Thank you AutopilotON and Bella 8721. I did replace the LED with the one I had connected to the X650. The problem still exists. So it seems that the LED is fine. I checked both LEDs with WKM which is installed on X650 and both LEDs work fine. I don’t know what is wrong. I wrote to DJI Technical support and got following response:
Good day!
Thanks for your email!
1. Kindly check all the connections on S800, especially LED.
2. Check the “problem” WKM, when you do settings in assistant software, and error alert jumps out?
3. Try to upgrade the firmware of this WKM; then let it work again.
Any further question, feel free to let me know.
Thanks!

I have checked all connections on s800 and checked WKM on assistant software. I get no error in assistant software and all switches seem to work fine. Also I have upgraded to latest firmware. Since I have no LED light on S800 I do not dare to fly the aircraft to see how it reacts on the air. I have done WKM setups many times and I am somehow familiar with it. I don’t think there is something wrong with assistant software configuration.
Any ideas?
 

saidquad

Member
Until now I had turned off the voltage monitor on assistant software because I do not intend to fly the aircraft until all hardware and software setups are properly in place. I just test the system with a 6s 3700mah lipo which I already have. Today I activated voltage monitor on assistant software and got PMU-ERR right away. Even though the battery voltage is 25.3 and first level protection is set to 23.10 and second level protection is set to 22.20 I get PMU_ERR. The Error Description states “please make sure the integrated connection among Battery, MC and PMU and further it reads PMU connection problem”.
Summary: If voltage monitor is deactivated, everything work fine on assistant software and I can start motors. The only problem is that the LED does not work. If the voltage monitor is activated I get PMU_ERR by software and LED does not work either.
Could the problem be 3700mah 6s? Do I have to by 10000mah battery to test the system?
Please help.
 

The mah of the battery does not matter. With the way you are set up it should work fine. I would try a different PMU and keep swapping wookong components from the copter that works until you find the problem. Sounds like the LED is fine so my guess is a bad PMU.
 

rocjock

Member
Had to bump this. Same problem. LED only responding in ATTI mode with 2 green flashes. No response from LED an any other flight mode. I tried three different power sources for the PMU. Same thing. I checked the connections. I'd really like to try 5.20 firmware. So I don't want to upgrade. Is reinstalling 5.2 worth a try? Any other suggestions?
 

saidquad

Member
My problem was solved by replacing the PMU. Just to mention my funny story once more. On a winter day in 2011 I bought a so called DJI professional Photography MR (S800) along with a pack of WKM. This pack was supposed to handle a 7kg loaded MR following instruction manual and the product advertisement. Since then I have replaced/added PMU, IMU, GPS, ESCs, arms, vibrations dampers, landing gear, LED and had troubles with many firm wares. Lots of email exchanges with DJI or dealers. Lots of time wasted to wait for upgrades or downgrades! Lots of money wasted for shipment or replacements. Lots of money wasted to replace parts after crash caused by flip or drift. All these because a young company was not paying any attention to the moral and the ethical side of the business.
 

Benjamin Kenobi

Easy? You call that easy?
I had this. It's just the LED has a loose connection. Power up and push/wack/wiggle the LED and it'll probably do odd things. Hope this helps.
 

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