BRArduPilotMega032.jpgWarning: If you power the APM 2.5 from a BEC you should include the diode fix used on the APM 2! It drops the voltage to 5.5V which is what the 3DR Power Module does!

 I've noticed a lot of USB connect issues lately and I have found some solutions. There are and could be several reasons for this. It could be hardware or software. It might be the connector on the board. It might be PPM and it might be something else. So if we all get together in one place we might have better luck solving these issues. So if you have a connect problem let's get to work on it here. Please be civil with me and I'll try and help. Together I think we can work this out. I don't care if you have a clone. Has nothing to do with finding a solution as far as I'm concerned. Be prepared to get dirty and have your camera ready and send screen shots too. Thanks let's fix this.

First things to try: PORT CONNECTIONS and COM PORT

Check com Port Speed in Mission Planner (115200)

Make sure of Com Port in Device Manager.

Turn off Bluetooth.

Remove any USB Devices you can.

Swap around USB ports.

Try a different USB cable.

Second things to try: SOFTWARE and DEVICE DRIVERS

Mission Planner checks for updates when it starts (if connected to the internet). Have you checked for Updates?

If Mission Planner just updated run threw the Port Connection and Com Port checks first.

Try installing USB Driver (APM 2)

If you have another PC install Mission Planner on it and see if it works on it.

Uninstall Mission Planner and reinstall from MSI

If you having HUD display not moving problems-

Try installing latest STABLE FIRMWARE BUILD from



Update/Reflash PPM Firmware




Mission Planner woes!

Make sure you have this font.

If you need to uninstall and reinstall Mission Planner

Make sure you go into device manager and uninstall the USB driver!

Make sure you have the proper .NET installed for Mission Planner (4.0 for the latest)

Make sure you install the MSI Mission Planner.

Make sure you reboot after making changes.



 I now offer a service to repair your APM for a $20 flat rate. If you send me your APM along with $20 and a self addressed return envelope with postage so I can return your APM to you if I can repair it or not. If I can't repair it I'll return $10 to you along with your APM.

Monroe King

995 CR 3040

Lampasas, Texas


 I'll be posting photo's/videos of repairs so others can learn too.

 I'm working on JTAG and UART0 work arounds that may give acceptable results for some.

Warning: Do not exceed Abs MAX input voltages when connecting the power supply or you will damage your board.
Warning: Connecting USB when you have input voltages at the high end of the range (near Abs Max) can damage the board. Disconnect battery before connecting USB or test input voltages so they are within the specified range.

Power OptionsNominalAbs MAXJP1 status
Power on Output PWM connector5.37V +-0.56VJP1 connected
Power on Input PWM connector5.00V +-0.255.5VJP1 connected

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  • anyone can help me please ?
    i've my board broke when i release the gps when it's on
    now the red and blue led stop blinking and can't connected to mission planner

  • Could you post a link to the "diode fix"?


  • Since sometime around a month ago I have also been bothered With USB Connection problems for APM. This is With several Boards and all working well earlier on the same computer.


    But yesterday I also had problem upgrading my New Martinez Board and came across this solution for Martinez Board USB problem. And this also solved my APM USB issues!

    The problem was FTDI driver Version 2.08.28 needing replacing with Version 2.08.24

    This document tells how to replace the FTDI driver to an older Version.

    Symptoms for me were connecting to Windows, hearing the sound of USB Device Connection, and after a few Seconds disconnecting again. Sometime also stay long enough for starting Mission Planner and then suddenly disconnect. Or a rare time staying on long enought to upload firmware and download logs. Not a very big problem but I have found it strange and thought it was my computer USB ports.

    But With the 2.08.24 firmware this now working as before With no Connection problems.



  • I seem to have similar issues as Jon. I have a APM 2.0 board purchased around this time last year but haven't mounted it on a quadcopter until now. I had it working just a week or two ago with Mission Planner, but just recently found that I could not even detect the device through Device Manager under Windows 8. I have also tried connecting the APM on a completely different computer with Windows 7 and nothing shows up under Device Manager either.

    All the LEDs work when I plug in the board via USB so I know the board is working. Occasionally, the Rx light is solid and the Tx light flashes rapidly (plugged usb only). I also know the board works via radio since when the ESC's and receiver are plugged in, the quadcopter can still be controlled. However, I cannot get any computer to detect the board so I cannot reprogram or calibrate.

  • Help desk contacted me today to send the board in for replacement.

  • Hello, I have a quadcopter and I am using ardupilot 2.5 with arducopter 2.9 . I have all ready to take off ( I tried one time and my quadcopter flew very nice ). I only want to use mission planer to fly but I dont know how to do it.

    I have visited a lot of pages where They only say how to upload missions but they dont say how to take off. 

    I have uploaded missions but I dont know how to play it.

    Please could you tell me how to take off with mission planer.


  • Thanks again for your help Monroe.

    I bought my APM a few months ago, plugged it in when I first received it and it connected fine. Upgraded MP software and now the board is not recognized on any computer (yet standard Arduino Uno is). I've tried all of your suggested troubleshooting.

    How long is warranty on these? This sucks for me as I'll prob have to pay shipping (im not in US) and wait another month to see it

  • Count me as another person bit by 3v3 regulator issues.

    One board started showing intermittent signs of 'ESC unhappy (repeating beeps)' at boot, unless power was first applied via USB, prior to applying battery power (via 3a turnigy BEC to input lead with JP1 disconnected).  That never occured until about a week ago.  The compass started showing intermittant unsual behavior, so I assumed the board was just suffering from 'accumulated trauma'.

    So, I replaced the first board with another.  This board actually complained about 'dataflash not present',  I didn't notice that initially, but did after I had already performed a number of test flights, and noticed the compass was 'odd'.  I was going to recalibrate using tlogs, but then saw any attempt to access the logs and it 'hung', upon boot via USB, it showed the 'dataflash not present' message.

    Both of these issues are symptomatic of the 3v3 regulator not functioning.  I did a voltage check, and saw 2.0 volts across the leads on the replacement board, and saw 4.0 on the first board.  I'm assuming both of those are significantly out of spec.  Excess voltage probably was 'marginally functional', insufficient voltage was just 'non functional'.

    I'd like to take you up on the offer for a $20 flat rate (times 2), to repair these APMs.  I'm hoping replacing the regulator will resolve the immediate issue on the 2nd board, and perhaps also resolve the issue on the first.

  • Got a reply from 3DR. Will try to replace the automux chip now - if I find it anywhere. Problem is that Mouser and Digikey want $20 shipping costs which is ridiculous for a $0,75 item! I asked 3DR if they can supply it.

    Good news is, it's a "long-legged" SMD part, so soldering by hand should be possible...

    Part#: TS5A23157DGSR



  • Hi Monroe

    Still having the issue (along with 3 others) where the APM will connect fine but then do nothing - no response etc.  The link strength indicator on the Flight Data page starts out at 100% then drops to 0% and a Red X appears.  This happens with USB or wireless.

    I tried resetting to factory defaults and erasing the epprom but still no better.  I can install new firmware and connect but then it doesn't respond.  Whats weird is once and a while it will work - but the next time I connect its right back to doing the same thing.


    Thanks for any help



This reply was deleted.


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