Intermittent receiver power off - RC Groups
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Feb 14, 2018, 03:38 PM
Ronaldo Nogueira
ronaldopn's Avatar
Help!

Intermittent receiver power off


Hi folks, I'm having an issue with a new plane. Maiden flight was yesterday no issues except one aileron linkage disconnected.
Today I did 3 more flights uneventfully. When I was preparing to take-off for the 4th flight the power turned off completely while I was doing the pre-flight checks. Since I video all my flights I was able to capture the moment. It was not possible to reestablish control until unplugging/ plugging the battery again. Turning Tx off/on did not work.

While I was still at the field I was able to reproduce the phenomenon 3 or 4 times by activating fail safe either by powering off the Tx or moving it too close to the receiver antenna (on the Taranis when signal is too strong the link is cut and fail safe activated, this is a normal condition predicted on the manual).
During these simulations, when the event occurred, again I was only able to restore the control by unplugging/ plugging the battery. So far I haven't been able to reproduce the even at home.

I'm inclined to replace the receiver just to be safe but I can't discard an intermittent issue with the SBEC too. This SBEC has been involved in 2 events with the same plane (Skyline Edge 30cc): an ESC fire and total crash.

I'm discarding the Tx as possible cause since I have been flying with my other plane for over 100 flights without a single issue. The event started with this new plane.

Here is the setup:
Taranis X9D original (not plus)
X8R receiver
YEP 20A HV SBEC
Hobbywing Platinum Opto HV 100A V3
12S 3300mAh lipos (2x6S in series)

2018 0214 120304 005 (0 min 21 sec)
Last edited by ronaldopn; Feb 14, 2018 at 03:43 PM.
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Feb 14, 2018, 04:22 PM
Ronaldo Nogueira
ronaldopn's Avatar
Just tried again at home to reproduce the event by pulling and shaking gently the SBEC wires but without issues, everything works as supposed to. I don't think it is related to a bad contact (unless internal to the electronics).
Ronaldo
Feb 14, 2018, 04:31 PM
Balsa addiction since age 3
ScottSails's Avatar
What does your telemetry logging show for voltage to the receiver?
Feb 14, 2018, 05:18 PM
Ronaldo Nogueira
ronaldopn's Avatar
Quote:
Originally Posted by ScottSails
What does your telemetry logging show for voltage to the receiver?
Telemetry logging was not activated
I have just checked on the Companion and have only logs from older planes. I completely forgot that it has to be activated for every single model.
Thanks for reminding me to do it. It would definitely have helped understanding the issue. I will set it now and maybe if I can manage to reproduce the event the log could help understand it better.
Ronaldo
Feb 16, 2018, 06:20 PM
Ronaldo Nogueira
ronaldopn's Avatar
Tried many times to reproduce the failure without success. I even attached the wings to simulate if the CF wing tube would present some interference. No matter how many times I turn OFF the Tx or move it close to the receiver antenna, the fail safe works as it is supposed to and power to the servos is never cut off. Turning Tx ON again brings everything back to normal.
I'm clueless, if I can't find any probable source I'll just replace the receiver (and maybe the SBEC) before flying the plane again.
Ronaldo
Feb 17, 2018, 01:47 AM
Julian T
Hard to see why failsafe kicking in would affect the sbec unless it resulted in a sudden huge current requirement . If you can't replicate the issue with logging I would personally either bin the rx or relegate it to small foamy use. That model is too nice to risk with a suspect rx.

Julian
Feb 17, 2018, 04:46 AM
Ronaldo Nogueira
ronaldopn's Avatar
The rx is out of that plane, no question about it. I'm just concerned with the fact that although I was able to reproduce the power off by activating the fail safe, the first and original event seems to have occurred during pre-fligt checks.
I'm inclined to replace all items in the servo power chain
Ronaldo
Apr 21, 2018, 10:59 AM
Ronaldo Nogueira
ronaldopn's Avatar
I should have trusted my instincts and replaced the SBEC.
I replaced only the Rx while waiting for the SBEC and also for the canopy latch I ordered. In the meantime I kept flying my beloved Raven 30cc.
Since I had tested the Yak many times at home without being able to reproduce the event I decided to take it to the field today. Well, I'm very happy that the issue occurred again with the plane still on the ground. I have already replaced the SBEC.

My theory is that the damaged SBEC is shutting down under a certain current value. The reason why it did not fail at my shop was probably because I did all the tests with the wings off (no aileron servos connected). At the field, after plugging the ailerons, the slightly higher current reached this "threshold" causing it to cut off.

The good news is that besides a saved plane (for the 2nd time) I also saved a receiver.

Ronaldo
2018 0421 093827 001 (0 min 54 sec)
Apr 21, 2018, 12:59 PM
KC
KC
Registered Loiterer.
KC's Avatar
Are the aileron servos humming at full deflection? At 00:05.
Apr 21, 2018, 06:50 PM
Ronaldo Nogueira
ronaldopn's Avatar
Quote:
Originally Posted by KC
Are the aileron servos humming at full deflection? At 00:05.
Fair question
They make some noise at full throw but there is no binding (hinges allow more deflection).
I checked voltage (with the new SBEC) on the system and it barely drops from 7.6-7.5V when moving all surfaces quickly or pushing them by hand.
I have just cut the heat shrink and found the damaged component.
It was most likely damaged on the crash.
Ronaldo
Apr 22, 2018, 04:53 PM
Ronaldo Nogueira
ronaldopn's Avatar
Everything seems back to normal with the new SBEC. Lesson learned: take special care when saving electronics from a crash.
Put 6 flights today, still playing with CG and mixes. Seems to be a decent flyer but overall I'm not supper happy with the plane and will probably put it on sale soon, I'm moving to 50cc so I'm finding 30cc too small now.
Ronaldo
2018 0422 112323 008 (5 min 6 sec)


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