RCU Forums - View Single Post - What The? Catastrophic failure under Spektrum DX9 Control
Old 03-23-2015, 07:30 PM
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Aerocal
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These things are impossible to track down on a forum without more data/clues.
There are several possibilities and possibly a combination of events. This kind of thing can happen way too often in something with higher than average servo load and tons of vibration. Helis or 3D planes. First most common is remote connector cables. You said it was Stubborn to Connect and then it Connected fine.That may be a clue.A big clue. Rx must have a remote to connect. If the cable connection is marginal it might be stubborn but finally connect.
Then normally if you get a momentary brownout or even a forced reboot from static or even possibly vibration and the cable is also in a marginal state it may refuse to reboot quickly if at all.
The remote cable may be marignal on the ground but in the air with high vibration it may not be working at all and your running on the main Rx alone without even knowing until the one Rx is shadowed and you go into Hold.
A couple questions though.
You said the AR7000 was new. Recently purchased new? Or been sitting around new? They have been out of production for awhile.We know it had a hard crash. If nothing else I would send it in to HH service and have them check it out.
How are you mounting your Rxs? Are you taking reasonable steps to isolate them from vibration?
Do you take extra care of your remote connector cables? I silicone or plasti dip where the wires go into the connectors.Not the socket but just where the wires go into the connector that plugs into the Rx. Tie them down to the fuse so they cant flop back and forth with g-loading. If you dont do that I found with 3D helis they are going to fail at some point likely sooner than later.

And the big one. Run telemetry. Log the data. Your radio is capable. Make use of it. I mostly run it on everything now. Set an alarm for low Rx voltage and 1 Hold on FL data. If a problem is developing you get warning before catastrophic failure. If you have a remote problem inflight you will generally get a momentary Hold with no noticable control loss long before you get in a place where you might get an extended Hold. Monitoring and graphing Rx voltage at the Rx(where its needed) will give a good idea of the heath of the whole power delivery system. Battery,switch,leads,connectors,reg/bec,smartfly/external bus,etc. There are alot of potential points of failure.Ive found that most components dont simply fail out of the blue.Ive seen Rxs just quit but the few I have seen were tied down tight straight to the fuse without foam or anything to isolate vibes.Sometimes it can be a combination of things. Problems generally develop until theres a failure. Like temperature. Motors dont just fry instantly.If you lean out for some reason (or you just miss your tuning) you generally dont know its going nuclear until it quits and likely the damage is done. If you monitor critical parameters and set limit alarms you can land before a failure. Without it your just fat and happy until something quits.
If you have those parameters logged in a file then many times a quick look at the graph and you can see exactly what happened with little guesswork if there a major failure. In demanding setups I cant see not using it both as a setup tool and a way to just keep tabs on the health of everything over time.
Without it everything is basically a huge guess.