cation3
Senior Heliman
Location: Smyrna, GA - USA
My Posts This: Topic Forum | I've spent the better part of three hours trouble-shooting a problem today. I had an AR7100R with the AlumaFX metal replacement sensor bracket installed in an OS 50 Hyper and T-Rex 600 for a little over a year now. I recently found a price on a new OS 55HZ that I couldn't pass-up. Today I installed it.
All I did was pull the old Hyper and stick the new one in. Due to carb arm and servo arm length differences, I decided to recalibrate the 7100's limiter. With everything back together, I initially powered up the electronics and as soon as the RX connected to the TX, the blue LED (power) started to flash and the cyclic servos freaked out. I quickly unplugged the battery.
Troubleshooting: RX battery on, no TX = 7100 LEDs were fine. Different battery, TX on = bad. Different satellite RX, TX on = Bad. Different RX (stolen from my N9, rebound), TX on = Bad. Switch connector removed, TX on = bad. Cyclic servos disconnected, TX on = bad.
See a pattern here? Neither did I until I disconnected the gov sensor connector, tried it and everything worked fine. In any configuration, with the sensor in the back of the engine and the connector plugged in, once the TX was turned on and the system fully powered up, the power to the RX went crazy.
Long story (a little) short(er). The aluminum Aluma FX sensor bracket was making contact with the sensor connections and caused a short. Somehow this caused the RX to reset continuously. THANK GOD this happened on the bench and not in the middle of a flight.
Perfect solution: replace the bracket with a non-conductive type. My solution: grind down the bracket and put heat shrink over the sensor between it and the bracket. I think wear and tear of the heat-shrink insulation will become a normal pre-flight check item.
Check yours before you have a vibe-induced short and an in-flight reboot / freak-out.
 
-Drew |
