Hi guys,

am I stupid or what's wrong? Building up the APM was easy, all sensors and outputs work fine. But why I cannot read a single input from the receiver? Tried >10 different firmwares and tested 3 different receivers with the APM -> test -> pwm, no valid input on all 8 input channels. APM is V1.4, it is connected with USB and has a BEC on Output 3. MUX-LED is always yellow and PPM-LED pulses all the time. The readings are always 1200 in each and every case.

Anyone could help? I cannot believe that the board is defect when all other things are perfect. Readed dozens of threads and wasted hours for debugging. :(

Best regards, Thomas

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Tried what Eric said again for Futaba R6208 SB & FrSky TFRSP in "Normal Mode" (14 ms) & "Highspeed Mode" (7 ms), no luck. Still no PWM readings from the receiver in test -> pwm. The thing is, that the PPM-LED pulses like crazy if any rx-input is connected, so I think the electronical stuff is ok.

Tested receivers:
2.4 FASST Futaba R6208 SB @ T8FG - Normal + Highspeed, no luck
2.4 FASST FrSky TFRSP @ T8FG - Normal + Highspeed, no luck

40 MHz Futaba FP-R118F @ F14, no luck

Maybe there is a special procedure to meassure somewhere on the board to verify that PPM/PWM is ok physically?

I was thinking the same thing, checked my PPM light and it's off. Whether I have my Rx attached or not, am sending signals or not, the light doesn't turn on. I arrived at the same conclusion as Tomahawk. Likely in my case this is a hardware issue. I hadn't thought of that possibility before because I order a pre-soldered APM.

I'm assuming you guys are powering your RC pins with an ESC as required. If so, contract the store you got it from for customer support. 

holy cow. I have the same issue. I've done it all.

I do know the receiver (tgy 9x) works as I assigned ch8 to th hold and when it's forward, nothing, when it's back (failsafe) servo's work gread through apm. APM seems to work great, EXCEPT, no radio input on radio tab. APM doesn't do anything when I manually set stabilize via planner.

ppm blue light blinks rapidly. I was about to flash the firmware until i saw I had to purchase a special link cable. I am powering via exc

Again: please contact customer support from the store you got it from. 

BTW, I assume when you say "no radio input", that's after clicking on "calibrate radio"

Yes, correct, Chris. Even went into cli mode and test -> radio.. all channels are set at 1200.


I purchased it 5/26/2011 from DIYDrones Store. I'm only posting the purchase and location as it may have been from the same "   " batch..


oh, and did email store. thanks for everything you do BTW.!!


This almost sounds like a bad hair day:-). If all your hardware is good then there is only the programming to educate.

There is no Firmware as many do not have a business here yet.

If your problem is a receiver channel to the APM there are those that can help.


Yes Chris, right on both counts; power is through ESC on channel 3 and the lack of input resulted from the calibration (but also checked through calibrating in terminal and checking the input feed in terminal also). I sent a mail to Udrones and we'll see what they say. Just unfortunate that I will have to send the board from Italy to Mexico and get a new one back again, I really can't wait to get my bird in the air and Italian customs tends to takes it's time.

Robert: any chance you can try with another radio? I'd like to eliminate some Aurora incompatibility before having you send it back.

Chris, mine is a Turnigy 9x.


I'm trying to use it on my plane with the new apm/imu(2650/1.4)

I took the receiver and plugged it into my older apm/imu (1280/1.0) on my hexa and it worked just fine.


So, it's something HW with the apm/imu(1.4/2650)  I'm guessing.

Alex: Got it. Probably something got scrambled on the APM board. The store should be able to repair/replace it. 

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