We had a very serious crash today testing XBee/joystick-level control where the vehicle lost all attitude control--the vehicle just pitched/rolled gradually, lost LOS, and eventually crashed (3 broken booms, 1 motor). We are running a sparkfun Explorer board and Digimesh 900. We were using the 'channels_override' action, mainly putting the copter in loiter via our own software client (AND this was working fine on the previous 5min of flight).
Assessing the damage, we found the explorer board is not getting 5V+. Somewhat explains why we lost control as the Xbees broke link. Checking the other sensors, we are getting a clean 5.01V for everything else (USB/I2C/AT328), so why would the telemetry port fail? Tlm port V+ and GND pin get nothing, 0.
Tried the explorer board on another APM and it powers up. So it's an Oilpan problem. Does anyone off hand know where the tlm port gets its power from (before diving into the schematics). Oil Pan has build date 8/19/2010.
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A little more investigation: the GND pin on the Telem Port has no continuity with any of the other ground points. Visual inspection says the pad looks fine, pins are fine, APM did not receive any impact (it's mounted in a shielded area) nor damage so I'm sure we lost comm in flight. Going to check the trace.