UMX A-10 receiver problem - RC Groups
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Nov 10, 2017, 07:38 PM
I'd rather be Flying
davecee's Avatar
Discussion

UMX A-10 receiver problem


Bought a UMX A-10 a while back. Seemed to work OK at first, but after a while it developed an unusual problem.
The receiver will almost never initialize when power is applied.
I often had to rebind to get it to work, and now even that hardly ever works. The TX will even say "bind complete" sometimes and it still won't work. I've tried three different transmitters and the problem presents itself the same way with each.
Batteries are good.
The motors will beep once, then twice to indicate the 2S pack, and then nothing.
I played around a bit and found this.
The unit will almost never initialize when all four servos are plugged in. The green LED on the board will blink and then go out, nothing works.
It will initialize 'Sometimes" when three servos are plugged in. The green LED will blink and then go out, nothing works. Except for "sometimes".
It will initialize almost 100% of the time when only two servos are plugged in. The green LED will come on and stay on and then there is a final beep and everything works.
It doesn't matter which servos are plugged in or where. Two servos, and it works, three servos and sometimes it works, four servos and it almost never works.
I'm able to bind it to different transmitters by having only 2 servos plugged in when binding.
Called HH and was underwhelmed by their lack of help.
Anybody have any inkling of what may be the problem?
Thanks, Dave
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Nov 10, 2017, 07:52 PM
AndyKunz's Avatar
Are your sticks and trims centered, model on a level surface, etc?

Andy
Nov 10, 2017, 09:32 PM
I'd rather be Flying
davecee's Avatar
Quote:
Originally Posted by AndyKunz
Are your sticks and trims centered, model on a level surface, etc?

Andy
Thanks for responding Andy
On previous attempts the trims were offset for level flight. Plane is level on a table.
I just reset the trims to neutral and tried again. Same result. 4 servos plugged in, no joy, 2 servos plugged in works fine.
It's quite a puzzling thing.
BTW, once initialized with 2 servos, I can then plug in the other 2 and it works fine. Never a glitch in the air.
Nov 10, 2017, 09:55 PM
If it flies, I can crash it.
rocketsled666's Avatar
Does it matter which servos you unplug? Do you get even a twitch from the servos at the point where it might be expected to initialize? I would be inclined to say the brick has a bad voltage regulator based on the symptoms. Except maybe it doesn't happen in flight. The fact that it doesn't happen in the air might just be luck, though, the way you fly. After it initializes, plug all the servos back in and then start throwing the sticks to the extremes like the RX does when initialization completes and see if the RX resets... if it's the regulator and you were more "ham fisted" on the sticks it might cut out in flight like it does when it tries to initialize.
Nov 11, 2017, 08:40 AM
AndyKunz's Avatar
It sounds like you have a failed servo there. I suggest you contact Product Service/Support.

Andy
Nov 11, 2017, 01:53 PM
I'd rather be Flying
davecee's Avatar
Quote:
Originally Posted by rocketsled666
Does it matter which servos you unplug?
Quote:
no
Do you get even a twitch from the servos at the point where it might be expected to initialize?
Quote:
no
I would be inclined to say the brick has a bad voltage regulator based on the symptoms. Except maybe it doesn't happen in flight. The fact that it doesn't happen in the air might just be luck, though, the way you fly. After it initializes, plug all the servos back in and then start throwing the sticks to the extremes like the RX does when initialization completes and see if the RX resets... if it's the regulator and you were more "ham fisted" on the sticks it might cut out in flight like it does when it tries to initialize.
Quote:
Others have said possibly the regulator. I just tried your idea of exercising all the servos rapidly for over a minute and it did not cut off, unplugged the battery and it then again would not initialize with 4 servos plugged in. FWIW, I've tried unplugging the motors and the symptoms are the same (no beep of course)
....
Nov 11, 2017, 07:53 PM
If it flies, I can crash it.
rocketsled666's Avatar
Still smells like a power problem. Too bad there's no way to force the RX to do a reset without power cycling it. Maybe one of the regulators doesn't come up fast enough if the load is higher... you'd know if you could get it initialized and then reset without cycling power and it reinitialized as expected.

Whatever is wrong with it, odds are you're not going to be able to fix it yourself, anyway. Time to open a service ticket with Horizon and see what they'll do to make it right...


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