All of the sudden, the output power rail on my APM stopped supplying power to the board. An electronician friend had a quick look for me and now the board can only be powerd by the input rail, with the jumper1 taken out. Another thing is my APM2.0 board would not boot up with the flash data card in place. Once it is taken out, the board boots up just fine. Any idea if I can fly without the SD card? Is it a result of the dead output rail power supply? My board has been flying the Skywalker just fine and never had a crash. Thank you for any input
3DR wrote me "...f you would like, you can send the APM2 back to the store for repairs or a replacement and we will check it here. You can also power the APM2 from the inputs, and you will need a separate power source to power the outputs rail."
Are there advantages/disadvantages from powering from the inputs. I guess this could be done with a Y on the BEC lead on the ESC? Is it better just to run a separate BEC from the battery? Can the USB and flight battery power at the same time the APM2 if you bypass the diode?
Thanks for your patience and help. The APM is quite new to me and I don't have an electronics background.
John, I'm not an electronics expert by far, so please don't hold me to my suggestions here.
I do a bit of hobby electronics. I make my own simple circuit boards and projects.
As you suggested, you could still use your ESC power output to power the input rail. We are supposed to only be using one of the ESC's BEC outputs to power the board as per the documentation. Ground should always be distributed to every component of the system. That said, you would want your ESC's to be connected to the output rail with the ground and signal wires only. You would carry ground and one of the ESC's BEC output over to the input rail.
The same could be achieved with a separate BEC but at the expense of more wiring, weight and just isn't necessary. As for powering the board via USB and BEC on input rail simultaneously is one I'm not able to answer. Please let us know if you get this information out of 3DR. There is potential for a voltage or current differential if the circuits are not isolated properly and I'm afraid the design of the board is beyond my understanding. (may very well be the problem with the APM2 as it stands).
Being open-source minded that 3DR is, it would be great if they would just clearly explain the problem we are seeing. I have to wonder if they are reluctant because of a design flaw. It happens, boards are revised and further developed. Companies take care of the mistakes professionally (3DR seems to be doing so), and continue to produce greater and greater products. I hope this is the outcome for us as consumers and 3DR as a company.
Thanks TJ, I decided to keep it simple and send the board back.
Follow-up. Got the board back last week, but am having a new power issue.
Who know where I can buy 3 zener diodes 1N5233BDITR
for my APM2?