Dear sirs,
I'd appreciate your help. My knowledge in electronics is not zero, but very limited.
I have an APM2.5, with Power Module, GPS, external compass and 3dr-like telemetry V1, on a plane, a big 2.2m span weasel-like flying wing, twin-motor, intended for mapping.
In the field I had some issues with the rudder's microservo and the nosewheel's standard servo, both of which were connected to the same channel, using a Y-cable. I figured out it could be bad contact, and connected one servo to the board, normally, and one (the nosewheel, since it wasn't necessary to navigation) to the RX, on a spare channel. I didn't figure out, at the moment, that by the rx's rails, it was being powered up by the board/power module, which should not be done.
The result: APM went crasy, and looking at the t-logs, it appears that apm received a reading from the rx of full acceleration and aileron/elevator commands many times. The model actually kept going from idle to full acceleration and aileron/elevator commands for about one or two minutes, until I unplugged the batteries.
Then when I recconected the batteries, there was no response. At home I found that only the "alive" led becomes active, but very, very dim. By USB it works normally, as well as with power from a 4.8v rx nimh.
Measuring the voltage of the Power Module, it brings to the board 5.5v aproximately, even when connected (and with the alive led dim).
I measured the internal resistance of the fuse and the zener diode close to I2C port, and they show 3 and 131 ohms, respectively. Nothing looks or smells burned.
I'd like to understand what happened, and how can I fix it.
Should I power the board from now on with a separate battery, or UBEC, or jut putting back the jumper and using ESC' BEC power (2 x 3A = 6A)?
Thank you very much for your help.
Eric
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