Replies to This Discussion

Permalink Reply by Michael Pursifull on August 1, 2012 at 12:53am

* No power - if your APM power LED does not light up, it is not a firmware issue. Troubleshoot as a hardware issue. Check to see if JP1 is present first. You might have toasted a diode on the board. You might have shorted the board out, or you might be connecting power or the RC unit incorrectly. See the next item before you do anything....

* See the ArduPlane orArduCopter manual for instructions, even if you are setting up ArduRover. There is more information about setup, hardware and software, for those two projects than any other project. I recommend you read one of these manuals from start to finish before you continue to play with your APM.

* For CLI information (in general) see here, here, and here, in that order. But go back to item #2, above, first.

 

Permalink Reply by Tom Gibson on August 1, 2012 at 7:26am

Okay, thanks. I have been fearing the hardware possibility and have double checked connections several times. Guess I'll do some more reading as you suggest and hope there is something I have missed. Don't understand how anything could have been shorted or fried though. Has ESD been an issue with these?

Also, if this is an onboard hardware issue do I have any options other than getting a new board?  Thanks

Permalink Reply by Michael Pursifull on August 1, 2012 at 10:19am

No. I believe the most common physical short that leads to damage is seen when connecting the RC controller. A user connects two sets of wires to power between the APM and RC receiver, but one of them is accidentally reverse polarity, bridging +5v and gnd. This short pulls too much current across the board and the diode is the first weak link, acting like a fuse. A revision to APM2 helped limit this, and 2.5 has even more protection. None of my APMs are protected against this, and I don't expect that kind of protection, you just have to be careful with raw electronics. 3dr do make improvements to help us protect ourselves, but ultimately anyone can find a way to defeat those protections on accident with incredible, unintentional, simple, boneheaded genius ;-)

Permalink Reply by Michael Pursifull on August 1, 2012 at 10:25am

Sort out what the issue is second, and contact 3dr support third. If it is a blown diode, they have been able to sometimes fix the board in the past, but don't jump to conclusions just yet. "happens often" and "happened to you" are sometimes worlds apart.

First, read all the docs, especially the early power and cabling stuff. Check your esc BEC output with a multimeter. Unplug everything and power up with USB only. Check for the presence of jp1. Remove jp1 and provide +5vdc and gnd on the proper input pins only, see if you boot, disconnect everything, restore jp1, and see if you can power with +5vdc and gnd on the output side. But read the manual first, and after all of this, you'll have a good idea of the nature of the issue, and if you have a hardware power-related problem.

Permalink Reply by Tom Gibson on August 1, 2012 at 3:00pm

I think the scenario you describe makes sense to me now. So if a servo cable was off by one pin, thereby connecting +5 to either Ground or PWM, would it cause the short you described?  I can certainly believe that could have happened unknowingly. (My eyes are not as good as they once were!) ;-)

Permalink Reply by Tom Gibson on August 1, 2012 at 4:07pm

Problem solved! (Now for the embarrassing part)  I learned that the servo cables do not function correctly when plugged in backwards (doh!) and I need to pay more attention to details!  I will be marking one side of those connectors to avoid future mishaps.

Thanks for your input. If nothing else I learned a few more pieces of the whole puzzle through this.

Tom