Replies to This Discussion

Permalink Reply by Vernon Barry on July 23, 2012 at 11:17am

What rail are you powering it from, input or ouput?

What loads (sensors, servos, receiver, lights) do you have plugged in?

What ESC are you using?

The jumper isn't a solder jumper, it's a physical pin jumper-are you sure you looked at the right place and read and understood the powering directions?

Did you possibly blow the diode on the APM 2.0 by powering the inpur rail with heavy loads such as servos attached to the output rail? (In other words, do not draw loads across the board from input to ouput or vise versa) Loads need to be at one end of the board or the other, the same as the power source.

Does your ESC have a BEC?

Did you at any time apply higher than 5 volts to the APM?

Can you verify you are getting power from your source?

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Permalink Reply by Antonio Rodriguez Buendia on July 23, 2012 at 1:25pm

The APM1  was flying perfect.And then stopped. I was fly more times with this board.

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Permalink Reply by Vernon Barry on July 23, 2012 at 3:16pm

Ok, you still didn't answer the questions which are also valid for APM 1.0.

http://code.google.com/p/ardupilot-mega/wiki/Hardware

What loads (sensors, servos, receiver, lights) do you have plugged in?

Can you verify you are getting power from your source?

Because it worked before and now doesn't, the only real options are:

Your BEC in the ESC failed from too much load (servos, and everything else).

Your load was so high or a short that burned the traces in the APM board. Again, this indicates possibly drawing power across the board to the sensors or servos and one of them shorting or drawing too much current.The board is not a good power distribution method and thus will blow out under the load of anything bigger than a micro servo when drawn across the board (not from one output to another). Say one of the channels for a camera gimbal that are not powered or plugged into the output rail, but rather some other power pins or source on the APM board that is being powered by the ESC/BEC. The board is resonably able to handle current from output to output pins next to each other as there are decent sized traces as a rail. Where you get into trouble is drawing current anywhere else on the APM as then, power is going through smaller traces.

I feel it is likely you have a BEC failure, because otherwise, you damaged the APM circuit board itself and the only method to try fix it is to jump some power into the rest of the board via any 5volt pin. I would find the fault first before even more damage is caused because doing this may let the magic smoke out if the short or excessive load is not identified.

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Permalink Reply by Antonio Rodriguez Buendia on July 24, 2012 at 2:49pm

I checked the voltage and good, 5V. Only I have the sonar connected. The ESC is programmable hobbyking 25A.
Thanks for your advice.

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Permalink Reply by Vernon Barry on July 24, 2012 at 3:13pm

Sorry it sounds like you have a problem board, but if it does work via USB, then try to power the board via any of the other 5 volt pins elswhere on the board (being that you have a 5 volt BEC) I say this with caution because if it fails again in flight, that's bad, but short of replacing the board, what choice do you really have?

There is the option of using the on-board regulator and that was covered in the directions too by moving the solder jumper. The regulator is not in the circuit normally so it's likely not the cause of this problem but could be a workaround solution. It's not a low dropout regulator so you cannot feed it 5 volts from the BEC and expect 5 volts to not have a brownout, and you don't want too high of an input voltage (say like 4 cells) because it's a linear regulator and higher voltage will hit it's thermal limit.

 

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Permalink Reply by Antonio Rodriguez Buendia on July 26, 2012 at 12:33pm

Hello, I have found the problem , the ardupilot had the multiplexer 74ATC157M burned. Well, Where buy i this multiplexer ?.
Thanks.

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Permalink Reply by Vernon Barry on July 26, 2012 at 3:44pm

So, I went to the schematic as that is a cheap limited production chip you listed and a bit hard to find. It's the equivalent of the chip specified in the schematic a 74LS157D . From your profile, you're in Spain? Farnel is pretty much worldwide, but they only listed the DIP version, not the SMT http://uk.farnell.com/texas-instruments/sn74ls157n/ic-74ls-74ls157-... I was just looking there to cut you some shipping expense.

That said:

Mouser has it http://www.mouser.com/Search/Refine.aspx?Keyword=74LS157D

Digikey http://www.digikey.com/product-search/en?lang=en&site=us&Ke...

Newark http://www.newark.com/jsp/search/browse.jsp;jsessionid=SQZYMFV0T4EV...

 

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