APM2.5 5V/Vcc Schematic

Frequently asked questions are about powering an APM2.5 or why the same does not work or why it has failed.

Here is a simplified schematic showing the major components of the 5V/Vcc circuit on the APM2.5

Target Audience: Readers who do not have Eagle or are confused about using it.

You Need: Basic electronic schematic reading ability


Note that I have separated the PWM Output section into the upper left corner with a heavy purple line that is bridged by the jumper JP1 on the APM2.5. This is to emphasize that diode D1 passes current through JP1 (and drops voltage). The remaining energy is then called 'Vcc'.  Everything outside the purple corner is Vcc.

This is why the USB will power the APM2.5 when connected to a computer/USB hub. Note the fuse on the APM2.5 side of the USB connector AND another fuse on the output of D1. Another change from APM2.0 is the D4 6.0V Zener diode. If an over voltage is applied to the board, D4 will crowbar what it can to protect devices.

As with APM2.0, any 5V source connected to any of the indicated Vcc/5V points outside the purple corner (with GND of course) will power the APM2.5.

Also of note is the 'Mystery Port'. This port takes 5VDC before D1 and the fuse and is called 'JP_VCC'. Other clues to the mystery are the lines to 'ADC 12' and 'ADC 13'. A mystery indeed!

Any errors in this drawing from editing are mine.

I hope this can be used as reference for solving problems.



27-FEB-2014 Eagle files are now located HERE


APM2_5 Simplified Power.PNG

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • Good question. I seem to remember seeing the file listed after the 'mystery module' was revealed. Where is it now?

    With the 'new' technical forum running, it may be cross linked over there somewhere. It may have been linked somewhere in this thread after the reveal.


  • Hi,

    Can I get a reference schematic for the 3DR APM2.5 with XT-60 Power module.


  • Hi

    On the power module, the big smd capacitor, what is the capacitance? it blew up on me, and I want to replace it.

    thank you


    • I checked my operational Power Module and if you are referring to the large yellow SMD cap, the numbers on mine are '107 25 310'.

      I do not think I have a schematic of the PM. You should be able to find one somewhere on the net.


      • thank very much, this should do :)

  • I am installing a new cx20 open source FC V252 V5.0  and need a pin out of the connections, especially the connection from the GPS.  Can anyone help?


    • I do not understand which connections you are looking for.

      This thread is to help with the +5VDC distribution and the upgrade to the Power Module (PM) addition to the APM 2.5/6.

      Are you asking about another flight controller?


  • Exactly what BEC (actually just a DC to DC converter) are you using? Does it have jumpers to set input/output voltages?

    What is the battery voltage on the red and black BEC input wires? (connect your meter to the red and black input)

    Remove the cable from the HK radio to APM and measure the voltage on the BEC output wires, red and black.

    Would the hobby shop you purchased the items from be able to assist you if you took the aircraft there?


    • Developer

      The only reason for the voltage to fluctuate is if there are two competing voltages connected together. Can you provide a more complete diagram and or pictures showing the wiring?

      • Dear Bill,Doug,

        sorry for my late reply but I was away from home for business..

        I attach a picture that shows a more complete connection diagram (sorry for the quality). I did try to fly the quadcopter as it is as the Vcc value now is in an acceptable way if you also agree..


        I also attach my yesterday;s flight log file. I would appreciate if you could give me your feedback as you are more experienced.. What I understand is that my quad is in the limit of its payload ability. A few more grams and it will be overweighted for good.

        Also, can i be confident with y mechanical parts (motors) that can fly for many hours or do I have to replace them every some hours ??? I have DJI E310 2312

        Best Regards,

        2015-10-28 00-17-34.log

This reply was deleted.


Santiago Perez liked Santiago Perez's profile
9 hours ago