Replies to This Discussion

Permalink Reply by Ravi on March 21, 2012 at 7:27pm

hi marion, go in setup mode and try calibrating the radio all 5 channels u are using again. the exit out of setup mode. and reboot the board.

Permalink Reply by Marion Wright on March 21, 2012 at 7:46pm

I did as you instructed and still no joy. I was hooking up a light controller from Dimension Engineering and accidently gave the APM two power sources. That's when I noticed the problem. The APM was working properly on all channels before I did this. Could I have damaged my board in error. I know the APM is very forgiving but I was in a hurry and very excited about my new lights. I wasn't paying attention.( my bad )

Permalink Reply by Marion Wright on March 21, 2012 at 7:54pm

The APM mission planner even shows that it is giving an output to the offending channels but I am getting nothing on the output signal pin for said channels. Even in MUX pass through mode (manual).

Permalink Reply by Marion Wright on March 21, 2012 at 8:28pm

I guess I just want someone to say " yes you f!*ked up! " so I can justify ordering another board. I would order an APM2 but I got to much money wrapped up in my oil pan. mag, pitot breakout and xbee breakout. I know the APM2 has these features onboard but I have an aversion to the color purple. Why can't it be red ? lol.

Permalink Reply by Tom Brecka on May 6, 2012 at 3:42pm

I see it has been over a month since this topic was discussed. Did you discover your problem? Get a new board? I have a similar problem, I have no output on CH 3, the throttle. I did not plug anything into the ardupilot board other than the usual ESC which had always worked with many flights, but 1st thing this season, I found no output for the throttle. I did update the firmware, being the only change I made to the system. I have since ordered a new ardupilot board from Sparkfun, version 1.4, my old one being v1.0. DIYDrones store seems to be a little back logged, and since Sparkfun had one available I ordered from them.

Permalink Reply by Vernon Barry on May 6, 2012 at 8:02pm

Let's use a some simple testing to figure this out. The PWM outputs are DIRECT connections to the mega 2560 outputs, so it should be trivial to upload a program via Arduino and toggle that pin high and low with a simple program and monitor it with a meter. It's just a pin, so either the 2560 is damaged, or you managed to kill the trace in the board. (Correction, that statement is true for APM2.0 but APM 1.0 has a mux chip for outputs 1-4). Sorry, I was hoping it was that easy to test, but APM 1.0 has the mux and that makes it a little more dificult.

So downloading the schematic we can open with free eaglecad (something everyone really should have when using any open source project such as this since they publish the schematics) http://stuff.storediydrones.com/ArduPilotMega_v141.zip

I could be entirely wrong, but if you damaged the mux chip (74LS175D), I would think you might have problems on outputs 1, 2, and 4 as well. It is possible to have blown the output driver on that pin of the chip, but given the power scenario you mentioned, the assumption is you damaged the power subsystem and thus the entire mux would have no power and thus no output on channels 1-4, but that's not what you said is happening. Either the chip is damaged or you have a wiring or ESC issue.

Again, schematics are key in troubleshooting and often can point you right at the answer. I wish I could just give you an easy test, but with the mux, even writing a blink code to upload is a little much for me tonight.

 

What happens if you plug a servo into channel 3 (ensuring you are still powering the APM with the ESC/BEC on another channel? This would also indicate a PWM signal is or is not present (assuming you don't have an o-scope).

 

 

Permalink Reply by Brad Smith on May 6, 2012 at 8:17pm

did you try a servo straight to the radio too make sure its not in your mixing and does it read correctly in MP tx setup? 

Permalink Reply by Tom Brecka on May 6, 2012 at 8:21pm

Yes I plugged a servo into the CH3 output and no movement. I uploaded the old servo/radio test routine without the oilpan and CH3 is dead. Just have to wait for the new APM V1.4 from Sparkfun. Maybe use the old APM for experimental add ons????

Permalink Reply by Brad Smith on May 6, 2012 at 8:23pm

i meant straight to the transmitter ?

Permalink Reply by Brad Smith on May 6, 2012 at 8:26pm

don't feel to bad i burnt one up too :)

Permalink Reply by Tom Brecka on May 6, 2012 at 8:30pm

No the receiver out is good, the MUX chip has no output on CH3. So I will fly the telemaster the old fashioned way until the new APM comes in the mail. lol I may fly it with the throttle direct from the receiver and the other channels from the APM board.

Permalink Reply by Brad Smith on May 6, 2012 at 8:36pm

i just had a thought i wonder if you could solder bridge it and bypass the mux ?

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