How to Avoid and Troubleshoot Quadcopter Issues (ESC, FC, Motor, FPV Camera)

There are many common problems new quadcopter pilots tend to ask. In this article we will try to help troubleshoot some of the common issues, some can even be avoided from happening.

How to Avoid Multicopter Technical Issues

For anyone who has experience of building quadcopters, should be familiar with all the critical parts of the machine. If not please take a look at the quadcopter hardware overview guide.

Technical hardware failure is inevitable. In this post we will discuss some hardware failures that tend to happen in a quadcopter, and how we could troubleshoot or minimize the chance of disaster from happening.

  • My Quadcopter won’t arm
  • Common FC issues
  • ESC problems
  • radio transmitter/receiver issues
  • Motors
  • VTX, VRX, FPV related issues

My Quad Won’t Arm

Possible Causes and solution:

  • We recommend “Switch Arming” rather than “stick arming”, make sure the switch works and can activate “Arm” in Modes tab in the configurator; if you insist in using Yaw stick to arm, make sure your yaw range correspond to 1000-2000 range
  • You Quad is not on a level surface. Calibrate your accelerometer on a level surface first, then try again on a level surface; This is a safety feature in Cleanflight and Betaflight, if you don’t want it, you can disable it by turning off accelerometer, or increase the angle in CLI: set small_angle = 60 (default 30)
  • CPU load is too high, you will also see a slowly flashing red light on your flight controller when this happens. To fix this, you need to either turn off some of the features, reduce the loop frequency (increase looptime), or/and turn off ACC
  • Receiver is not bound or not working correctly
  • Make sure all the RX channels are mapped correctly
  • Your lowest throttle is higher than “min_check” in Betaflight/CF. You can either increase min_check, or calibrate your throttle range properly

Flight Controller Failure

Mini Quad flight controllers have actually been one of the most reliable components for me personally. Common issues could be:

  • Cold/dry solder joints – to RX this means failsafe kicks in without losing signal (no RSSI warning), to ESC this means the quad doesn’t response to TX stick for a brief moment or just drop out of sky. This is a good example of “how not to solder
  • FC shutdown – you quad drops out of sky unexpectedly. Usually this is caused by lost power to the FC: maybe a cold solder joint or loose cable, or maybe it’s the voltage spikes in the power. Bad voltage regulator could also be the cause
  • Moisture or water gets into the FC and shorts the components, causing the quadcopter to fail – try to avoid flying in the rain/snow, or above water, wet grass etc. To prevent this issue you could also apply waterproof coating on your FC or any exposed PCB in your quadcopter

ESC Problems

The most common ESC (Electronic Speed Controller) problem might be burn-out, or even catching fire.

There are many situations where the ESCs can be burnt out.

  1. Overloading, i.e. motor draws more current than what’s they are rated for over a long period of time and causes overheat
  2. Damaging burst current during a crash
  3. Physical damage, e.g. hitting a rock, or struck by a spinning propeller

To avoid these problem, always stay within safe limit when picking motors and propellers combo. It would be nice to have current sensor in your quadcopter and have the current draw displayed in OSD. Make sure your PID is properly tuned, bad PID can cause vibration and excess current draw. Also make sure the ESC’s are getting good airflow.

To protect ESC’s from physical damage, many people simply put a blade of a propeller on it and wrap it with tape or zip tie.

All soldering and wiring should be kept well insulated from each other, and proper heatshrink should be used for electrical protection. For carbon fibre frames, wires should be handled with extra care as carbon fibre is conductive. They should be insulated from each other.

Radio Transmitter/Receiver Signal

When it comes to radio problems, the first thing I can think of would be loss of radio signal. These might be the causes:

  • RX lost power
  • Your antenna got chopped off by propellers
  • RX antenna is blocked by carbon fibre frame

Also make sure there is nothing blocking between you and your aircraft. The frequency used in our radio is 2.4Ghz, while it’s has moderate penetration ability, it can easily be blocked by concretes and hills. Make sure your transmitter antenna is aligned with your receiver antennas to get the best possible signal.

It’s good to have some sort of RSSI signal strength alarm or warning. Decent radio transmitters come with this feature such as the Taranis, it shouts at you when signal strength drops below certain level so you can make a turn in time. Also make sure failsafe is setup properly on your radio receiver and flight controller.

Lastly, range check your radio if you are flying in a unfamiliar environment, “knowing one’s limit” was the wisest lesson I ever learnt.

Motors

Mini Quad Motors are generally quite robust and they don’t break easily. But since they are very exposed to crash damages, ripped wires, bent shaft or loose magnets can happen. Some would attempt to fix them but due to the technical difficulty it’s easier to just buy a new one IMO.

Hot Motors

Hot motors aren’t a good thing: it shortens motor life and eventually the motors can burn out.

Two things tend to make motors hotter than they should:

  • “Over-prop” – using propellers that are too large to handle
  • Vibrations and twitching in your quadcopter, rapid change of motor RPM will cause motors to overheat

To prolong the life of motors, it’s important to keep them as cool as possible in flights. This involves tuning your PID properly, clean your power system noise with capacitors. In extreme cases where nothing seems to help, you can also consider soft mounting your FC or even motors.

Another common issue with motors are long screws. If screws are too long they could touch and short the wildings in the motor. This could cause the motor to overheat, or even burn out the motor. Here is how to determine the correct length for motor screws.

Some motors are hotter than others?

If 1 side of the motors are warmer than the other side, this usually suggest there is a problem with center of gravity (COG). For example if the back is heavier than the front, then your back motors are going to work harder to keep the craft in the air and thus get warmer. A quick fix is to shift your battery or HD camera to keep COG in the centre.

Video Transmitter/Receiver Signal

If you fly FPV, the last thing you want is to have problem with FPV system. When losing video you have absolutely no idea where the quadcopter is flying into, and this is extremely dangerous to people around. When this happens the best thing you could do is probably cutting throttle immediately, let gravity take care of the rest and crash your quad in to the ground.

Most people fly 5.8Ghz these days, and penetration ability sucks, and this is the main cause of lost of signal. Don’t expect it to work if you are flying in the wood or over the other side of the building. Trees and walls are very effective at blocking 5.8Ghz signals.

Getting jumping lines in your video during flight? It could be noise in your power and adding some capacitors could help. Also make sure your FPV gear shares a common ground (ground are connected together).

To get the best possible signal, FPV antenna is probably the most important factor. Check if you are matching SMA or RP-SMA correctly, and if you are using both Left-hand and right-hand antennas.

And again, range-check your equipment before you fly in a new environment.

Final Words

There are endless possibility when it comes to issues in a quadcopter, if you had an unusual problem that wasn’t mentioned please let us know in the comment section. It could save someone hours to find out the problem.

Before a flight session, remember to check all of your bolts and nuts are fastened, especially the motors. After a rough landing or crash, triple check your props and frame for damages as well, do not fly with propellers with crease lines.

31 thoughts on “How to Avoid and Troubleshoot Quadcopter Issues (ESC, FC, Motor, FPV Camera)

  1. Rebecca

    Hiya, my quad opted suddenly won’t respond to the controller, lights are flashing on both but nothing working. Please can you help, this is a recent gift.
    Many thanks

    Reply
  2. Becca

    My Mini reddie isn’t taking off?Handset beeping but drone not responding to it.Know what it is?

    Thanks 👍🛠⁉️🕸😎

    Reply
  3. Tamal

    Hey Oscar! Hope you are in good health. I am having a very frustrating problem with my quadcopter. I made it with Arduino following Joop Brokking’s code. Now, the motors are rotating fine if I am powering the arduino via my laptop(USB port). But whenever I am trying to use my battery as the power supplier through the Vin pin of Arduino,,, the more I am increasing the throttle, the receiver gradually loses the power. So , before even taking off, the motors stop to functoion. After a couple of seconds, the receiver again gets adequate power, and all of a sudden, the motor starts to rotate and again the receiver loses full power. The same cycle repeats again and again. I am using a 3500 mah, 35C, 11.1 V Lipo Battery, Arduino Uno, 1400KV brushless motors. Please help

    Reply
  4. Rahul

    Hello Sir I make a quad copter but when I bind in reciver ,then before binding it’s blinking light from receiver.but when I bind the reciver it’s continues on receiver light ,but my quad copter is not start after some time light is automatically off can you give me some suggestions what can I do ,then my motor will run.

    Reply
  5. Ben Shamblin

    Hey Oscar, I know this is an old thread but please be kind and help me out here.
    I am having a persistent and very irritating issue. In flight, sometimes my FC and ESC’s will recalibrate. It happens randomly, and unpredictably. I can’t for the life of me figure it out. I’m running a Lux V2, Aikon SEFM 30a, RRosd/PDB, and DYS FIRE motors.

    Reply
  6. Ren Medalla

    Hi Oscar,

    I hope you can help me out with a puzzling problem about my first quadcopter build of a FlexRC Mini Owl. During testing the 50C LiPo drains alarmingly quickly. Below are the major parts of the “power train”:

    – BeeRotor BRF3 FC
    – FVT Littlebee Pro 20A x4 ESC
    – Dys 1104 6500KV motors
    – Furious FPV 1935-4 (1.9″ 4-bladed) props
    – Helipal’s Storm 11.1V 450mAH 50C batteries

    The BRF3 has been flashed to the latest versions of Betaflight and MinimOSD and the Littlebee ESC is also on the latest BL-Heli firmware and configured according to Joshua Bardwell’s excellent BLHeliSuite tutorial. Betaflight has also been properly set up and calibrated – except for the PIDs which have been left stock because I have no idea how to mess with those yet. The stock PID numbers seem to be pretty high compared to what my Helipal Storm Owl is set to but I figured that stock should be fine (I’m probably wrong).

    So after I’ve done all the configs, bound the Furious Mini Rx receiver and figured out how to enable telemetry, I attempted my first hover test. the Mini Owl lifted off at around 50% throttle but seemed to be really twitchy even in Angle mode but I thought that could be due to the stock PIDs in a micro frame.

    To my shock, I almost immediately started getting low battery alarms from what was a fully charged battery. It must have been hovering at half throttle for less than 30 seconds before I saw the voltage drop to 10.5V and below. After I disarmed the quad the battery recovered to around 11.5V. Wishing to blame it on a bad battery I tried my other 2 450 MAh batteries and I got exactly the same result. However, no magic smoke appeared and I couldn’t smell anything burning so I have no Idea where all those Amps went. I couldn’t find anything on the web about the extreme drain I’m experiencing, so I’m at a loss and need help figuring out where I went wrong. I made sure to select the parts that were either recommended (motors and props from the FlexRC site) or familiar (my pre-built Helipal Storm Owl uses the BRF3 and Littlebee ESC) thinking to avoid major issues with compatibility or suitability.

    Could the ESC be faulty? The motors do not seem to be damaged or burnt out and they do work because the quad can hover. Could the batteries not have a high enough C rating? but 50C should be more than enough to power the Dys 1104s. I have no real experience yet so I’m hoping that you can give some advice.

    Best regards,
    Ren

    Reply
  7. Ellman

    Hi Oscar,
    I am having a problem that is driving me nuts.
    I am a first time quadcopter builder.
    I am building one as a project with my son. We got everything assembled but when we turn it on the motors don’t spin.
    We are using the MultiWii Pro ATMEGA 2560. We have 2 of them. One was from ReadyToFlyQuads and had all the connections pre-soldered. The other we soldered the connections ourselves.

    Here is what we have done so far:
    1) We assembled the frame
    2) Attached the motors
    3) Attached the ESC’s
    4) Soldered the connections for the ESC’s to a power distribution board
    5) Connected the Receiver to the MultiWii
    6) Connected the ESC’s to the MultiWii
    7) Tested the connection of the MultiWii by connecting it to my PC using the MultiWii software
    8) Verified that the MultiWii is connected by tilting it around and watching the software show me the direction it is tilted
    9) Verified that the ESC’s and Motors work by connecting them directly to the Receiver and bypassing the MultiWii then playing with the transmitter and watching the motors spin.

    Unfortunately, as soon as I connect the ESC’s to the MultiWii, the transmitter has no affect on the ESC’s.
    Is there anything you can suggest we try to get this working. I am sure that it is some kind of stupid newbie mistake.
    I can send you the Config.h file for my MultiWii that we uploaded with Arduino if that helps.
    We only used the Arduino config.h for the board that we soldered ourselves. We didn’t change anything for the pre-soldered readytoflyquads board.

    Thanks in advance for your help.

    Reply
    1. Oscar Post author

      sorry i don’t have any experience with multiwii (used it but that was 3 years ago).
      you plugged in the battery right? can you verify if the TX is working on the GUI when lipo is plugged in? (remove props first)

      Reply
    2. Steve

      Did you calibrate the motors in the MultiWii . just a thought as had the same problem in a beta controller.

      Reply
  8. Akshit

    Hi Oscar
    I have a quad copter it was working perfectly fine but when I was flying it suddenly one of the prop stopped working I am confused that it is a wiring problem or motor I checked the wiring its all ?

    Reply
  9. BK

    Hi Oscar,
    I am having this same issue
    1. My miniquad wont come down after i armed and try to hover, in order to make the quad drop, i need to disarm.

    Before this i wasnt have this prob, just after few weeks after i changed the frame from qav210 to qavX..i flew the qavX without no prob for about 3 flights.
    Same setting. i thought i was having the fc issue, changed it, same problem. then i also replaced the new x4r receiver. same problem occured.
    Maybe u have the experience regarding this problem.
    I really new help. Thank you.

    Reply
    1. Oscar Post author

      very strange, what does the quad so while it’s armed, and your throttle is zero?
      do you have airmode turned on? what’s your min_throttle?

      Reply
  10. maheta ankit kamaleshbhai

    i cant take off my quad copter because of the rotation of the motors and fan of the motor guide me that which type of motors are used for the that and also which type of fan are used for that so i can fly my quadcopter..

    and also it has no more control because of the its light weight

    it just rotate around the soil…..

    Reply
  11. Joel LaRosa

    Hi Oscar,

    Finally some straight forward advice on ESC faults!

    I’m new to quad’s and got a second hand BNF Storm SRD280. I’ve flown it about 5 times whoever today my SW motor gave up and wouldn’t rotate.

    I’ve put it on another ESC and it runs a bit skitty but I think that’s because it wasn’t collaborated.

    I’ve re collaborated the board (CC3D) and the SW is still not playing. So I assume it’s the ESC that’s died on me, do you know of a way I can check this with LibrePilot or any other software?

    Thanks in advance

    Joel

    Reply
  12. Qhris

    I was having major problem with my quads dropping out of the sky with a lost signal on my Turnigy 9X. 4 major crashes later, I finally figured out that it is a bad idea to tape the antenna wire to the frame or onto a motor boom. I created an antenna mast with a heavy zip tie and attached the antenna with some heat shrink, No more lost signal! Go figure.

    Reply
  13. Stephen Craig

    Hey Oscar, thank you for the very informative article. I have an Eachine Falcon 250 that had an ESC go bad. I replaced the ESC and it flew just fine for about 45 seconds before it did a quick barrel roll, crashing to the ground. Now whenever I plug in the battery the quadcopter will rhythmically beep and twitch all 4 props. My transmitter isn’t even picking up a signal from the receiver. Did I completely fry something? Thanks.

    Reply
    1. Fabrizio

      Hi Stephen, did you fix your problem with the falcon 250 and the twitching motors ? I have the same problem with the same copter… let me know thanks.

      Reply
  14. Laggert MeLackey

    I just wanted to thank you for the video showing different failures, I’ve had a couple bad squealing motors for awhile, but I also suspected at least 1 ESC was bad. After some particularly long hard runs I’d sometimes get the effect you showed in your video as the ESC petered out.

    Anyhow your video should go down as a classic ESC failure on a Quad, well done and you helped me a ton.

    Reply
  15. barrie

    Hi Oscar I have quadcopter v666 I opened it Christmas morning manage to get it going and one of the blades got cort and I lost a scroow after replacing the blade ,I set it going. and it kept listing to the forward left ,after looking online I thought I might have a problem with the motor so I ordered 2 new motors and replaced the motor still have the same problem .can anyone help

    Reply
  16. Niall

    Hi Oscar

    I have one issue with a piece of advice you gave in this otherwise great article;

    “To check, I spin the motors with propellers mounted on, if one motor is harder to spin (you can feel the resistance), and it stops earlier than other motors, that is a sign of bad motor that needs to be replaced.”

    this is not a very good method of testing to see if a motor is bad. As Bruce (of RCmodelreviews) has pointed out in this video,

    https://www.youtube.com/watch?v=RaCjJbEB078

    ESC FET drag can cause motors to not spin freely… this doesn’t mean that they’re bad!! Don’t go replacing motors that aren’t bad! Otherwise thank you for your helpful article.

    Reply
  17. Jimmy Louton

    Hi Oscar! I thought I’d reach out for some help, you DO seem to be rather well versed on most issues… I have a quad with a CC3D flight controller, 20A ESC’s, 2204 2300kv motors, 6045 props and I run a 2200mah 45c Lipo. My quad is fairly new, I haven’t even replaced a prop yet. MY PROBLEM: vertical full throttle take offs “punch outs” make my quad roll to the left at about 20 feet, every time. I have been able to save it from crashes because I know what is going to happen, I’m prepared. I put test marks “home” on the props, I know they are not slipping. Besides this issue, the craft flies great Any ideas of what could be causing this? Thanks

    Reply
    1. Oscar Post author

      you probably have done it already, but still first thing to do is calibrate your ESC properly, check PPM Min/Max values in BLHelisuite make sure they are the same on all ESC.
      if the problem still happens, then it would be the quad’s COG not centre, or motors having mechanical issue.

      Reply
  18. Patrik

    Hi Oscar, my quadracopter L6052W flews only a few seconds (5 sec) and then drop and when i want to fly with quad he dont react on controler. Is it a problem with quad or with the controler ? It push left stick forward and the quad dont fly,he fly only when i swith on the quad and the controler agayin.He fly only 5 sec.

    Reply
  19. Roger Paull

    Hi, I have a 250 qaudcopter with 12amp ESCs, naze32 FC, emax 2300kv motors. I use a 2200mah 3s lipo, and currently have no camara gear mounted. Today I flew into some branches and my quad dropped and hit the dirt/grass in my backyard kinda hard, after that if flew like crap. I recalibrated magnetometer and accelerometer, but it still would start to drift wildly until my transmitter stick could no longer compensate even at full range. It seems a bit jumpy when hovering and manually compensating for drift. Any ideas what it could be would be helpful.

    Reply
    1. Oscar Post author
        replace the props
        Calibrate your ACC again (if you fly in self level)
        check your bolts and screws of the FC, motors and frame
      Reply
  20. mrtimmberly (Tim)

    Hey Oscar, great article!

    I’d like to add regarding your soldering point, to make sure all wiring is well insulated from each other and use heatshrink for protection.

    Also if you have a carbon fibre frame, be aware that it is conductive too so wiring has to be insulated from the frame.

    Vibrations can cause wiring shorts/failures too.

    Cheers :)

    Reply

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