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RG 831B Receiver problems

Old 11-12-2014, 09:33 PM
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Ricko1
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Default RG 831B Receiver problems

In the past 3 months at my local flying club we have had 3 incidents with suspected malfunctioning RG831B receivers. I have raised this issue to hear if any other users have had similar problems.

This is not a JR bashing exercise.

Here is a bit of background information - between the three of us we have many decades of flying experience and all with JR radio gear. Previous to these incidents we have been totally satisfied with the reliability of JR equipment.

Of the three planes involved 2 were 30cc warbirds and 1 x 100cc aerobatic plane. One warbird was a total loss and the other was a very close shave with intermittent loss of control. Both behaved as if 1 or more channels (aileron in particular ) browned out. Neither plane went to fail safe.

The third incident was last weekend and involved the 100cc plane. Whilst flying, the aileron on one wing went to full deflection without any input from the radio. With a lot of skill the pilot was able to land with only minor damage. We suspected a faulty aileron channel. This was confirmed by swapping the other wing into the No 2 channel. As each wing had two servos for operation we could conclude that it was not a servo problem.

Radios used were: 2 XG8's and 1 XG14.
All planes were gasoline powered.
All had RG831B receivers.
All planes had been flown successfully many times previously.

I have used RG831B for the last couple of years in my nitro planes without any problems and continue to do so but have now switched to RG731BX
in my gas planes. The other pilots are considering doing likewise.

I have a suspicion that maybe the vibration from the gas engines may have a detrimental impact on the 8 channel receivers.

Like I said previously - this is not a brand bashing exercise but I would be interested to hear of any similar problems from other pilots.

I would appreciate if the moderators could delete any non constructive comments.

Cheers,

Rick

Last edited by Ricko1; 11-13-2014 at 12:35 AM. Reason: incorrect grammar
Old 11-13-2014, 12:02 AM
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chuckk2
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I don't know about the innards of the RG831B. But, assuming that it uses surface mount/ball soldered IC's, I'd suspect that the vibration popped a solder joint or so.
(I ran into this on a couple of 8 channel other mfr/model RX's.)
Old 11-13-2014, 12:32 AM
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Ricko1
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Thats what we suspect but without the technical skills to test that idea we decided to avoid those receivers and go with the X bus receivers. Besides ,you get heaps more channels and you can never have too many.
Old 11-13-2014, 06:30 AM
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What servos were you three amigos using ?

I have two of the 831's and they work fine with Futaba (and JR) servos.

If you recall, the first batch of Futaba 2.4 receivers would not work with Hitec servos. The RX output voltage was not high enough to run the Hitec servos. Hitec could modify them to work by changing a pull up/down resister. A guy I fly with kept having glitches with a Futaba 6008HS and Hitec servos. Turned out Hitec replaced a motor in one of the servos. It was shorting and resetting the receiver.

All receivers and servos are not compatible. All receivers and BEC's/Regulators are not compatible. Are you running separate ignition packs?
Old 11-14-2014, 10:04 PM
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Ricko1
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You raised an interesting point about the servos.

First setup : All JR servos,
Batteries : NiMH's with separate ignition pack

Second setup : All Hitec servos
Batteries : 2s LiFe with ignition fed through a Tech-Aero "Ultra IBEC"

Third setup : have to check with the pilot but I know he had a PowerBox system in his. Not sure what model.

The only equipment that was shared between all three planes was the receiver.

In our club there are only 4 flyers using JR DMSS radios and three of us have experienced mishaps with our planes that appeared to be linked to radio problems. Our collective confidence in this receiver is lost. When we have big dollars invested in these planes the last thing you want is to be unsure of your equipment.
Old 11-15-2014, 10:58 AM
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You should make every attempt to duplicate these problems on the ground in a flight stand. At what range were these problems ? You can put the TX in range test mode and back off a few hundred feet to simulate extreme range. What were the recorded max/min RX telemetry voltages ? Test with the engine running and not. Jerk the sticks around like you were doing 3D.

Are all of you guys getting your extension cables from the same aftermarket place ? A guy at GMA who manufactures planes was having these same kinds of problems for months. All manner or things were accused including chrome monocote flapping in the wind. The end result was aftermarket extensions made by illegal orphans in a basement somewhere.

Lastly there is not a temperature range specified for these receivers. Do you have open canisters in the fuselage, a big clear canopy, and no air vents. This caused problems with the original 6014FS receivers. I put two in a pyrex bowl in my oven and heated them up to 140F. Mine worked fine.

Good luck with this problem.
Old 11-16-2014, 01:07 AM
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Ricko1
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Thanks for the input Four Stroker. I can see where you are coming from - Between us we have thrashed these ideas to death over the last month or so trying to figure out if there was a common source that could explain what we have experienced but we can not find it. Maybe it is our location - we have high voltage transmission towers nearby but for our own peace of mind we have decided to ditch the 831's in the bin and from now on only use either the 7 or 11 channel X Bus JR receivers.
Thanks for your interest,
Rick
Old 11-16-2014, 02:33 AM
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Interesting.... no similar incidents to report.
Old 11-16-2014, 01:49 PM
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You would be doing a service for rest of us DMSS receiver owners if the faulty receivers were sent back to your distributor or to JR PROPO. If it is a vibration problem that is causing a solder connection to break, switching to the seven-channel receiver may not provide any certain relief. It could be both receivers come off the same assembly line and share the same frailty. If it is a manufacturing problem, XBus would make the situation worst. Instead of just one channel going kaput, every channel on the bus will go out.

I own no RG861B receivers and the one RG731BX I have hasn’t given any problems. It has been in use for a short time. Also it is in a mid size electric so the vibration is low.

Allan
Old 11-16-2014, 08:48 PM
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Ricko1
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Originally Posted by AA5BY View Post
Interesting.... no similar incidents to report.
Prior to starting this thread I did a search of the various R/C forums to see if I could find any reports of faulty 831's and only found one and that had no explanation in it. I wanted to see if there were any other flyers who had a similar experience as ours. Will give it a bit longer but if nothing else turns up may have to put it down to "***** happens".

Rick
Old 11-21-2014, 08:29 PM
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This morning I spoke to one of the other pilots who I had previously reported as having problems with his ailerons. He told me that on further investigation it turned out that one of his servos had malfunctioned. His 831 receiver worked fine.

I started this thread to find out if there was an inherent problem with JR 831 receivers. It looks like quite a few pilots have seen this thread and yet there have been no reports of similar problems. With this information it would appear that the cause of our problems lies elsewhere. This has restored my confidence in JR and I for one will happily continue to use their products.

Thanks for joining in the discussion -

Rick
Old 11-22-2014, 04:00 AM
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Confidence means a lot... when a valued plane is dependent upon the reliable performance of the control equipment. Kinda hard to have fun, with worry on the mind.

I had an event with my XG-8 that chipped a little crack in the confidence. On the base leg of a landing approach, the plane suddenly rolled and while some effort helped, adequate control was lost so I cut the power and it went in and wiped out the front section, rudder, bent the wing tube, ripped out a root rib, wing tips and minor abrasions. Though I and others hadn't thought it had gotten too slow to stall, there was a cross wind in our face and we suspected a tail wind gust hit it and it stalled.

A year later after rebuilding, the cause was discovered. When hooking the choke and throttle servos up, it was powered up for the first time since the crash. I activated the gear switch to move the choke and it didn't move, but something was moving... what was it? I'd taken the stabs off when doing the repairs and discovered that it was the elevator servos that were responding to the gear switch. In pos 0, they went hard over in opposite directions. Pos 1 they centered and in pos 2, they went hard over again opposite to pos 0. edit note: the choke was actually on the aux 2 ch and I'd forgotten.

There were no mixes or reasons why the gear switch should affect the elevators, more especially the primary elevator. The gear ch was slaved to the elevator ch but that is supposed to render the gear ch unresponsive to the gear sw. The instruction manual even illustrates doing so. Finding no way to stop it, the gear ch was unmated from the elevator ch in the wing configuration screen. At that point, operation seemed normal, the gear switch no longer had control of the elevator ch.

When mating the gear ch back again to the elevator, operation was normal with the gear sw having no effect upon either the elevators. Horizon offered that unless the problem could be duplicated, they had nothing to fix and suggested upgrading to latest firmware, which I did as well as change the elevator slave from the gear ch to the aux 2 ch and put the choke on the gear ch.

My only explanation is that it was what the electronics industry calls a single event upset. I'd flown the plane for a year with that config and have now flown another plane for two years with the same config.

Is there a slight crack in confidence... yes.

Last edited by AA5BY; 11-22-2014 at 04:05 AM.
Old 12-01-2014, 11:51 AM
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" He told me that on further investigation it turned out that one of his servos had malfunctioned. His 831 receiver worked fine. "

That's kind of where I was going. "I ain't got it !" is usually followed with blaming something, not necessarily anything related.

It took me a while to program the first XG14 thing. The manual or translation is not great. When a function/channel is inhibited it keeps right on going. Anything that is mixed into it will affect the output. Inhibited only means that it is not directly connected to a stick, switch, lever. The output is neutral if nothing is mixed into it. We fix radio programming problems every week. When many screens interact, it is difficult even for us old guys to figure out. Most but not all weird occurrences are that it did do exactly what it was programmed to do even if that was obscure.

The word EXP has at least three meanings:

Soft center as usual
Curve smoothing
eCCPM compensation for rotary servos. There are some linear micro servos but I think this software is actually ancient !

And by all means put every s/w update in the TX. All radio manufacturers fix bugs secretly in updates. Don't think that since you don't need any of the new features in the update that you don't need the update. Our transmitters are like space probes. You launch them and then fix the software bugs later.
Old 07-18-2015, 12:12 PM
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Hey all,

I owned an XG8 and upgraded to an XG11.

When setting up a new plane (Hangar 9 P-47-40 30cc with DLE55), I used a mix of servo manufacturers, PowerHD and Spektrum.

I found that when using the Spektrum servo on the throttle with the PowerHD's (8309tg's), this spektrum a6130 (I think was the model) caused ALL servos to act erratically, buzzing about and actually rebooting the RX. This was using a JR 831b receiver along with a SmartFly EQ10. As soon as the Spektrum was pulled out of the mix, all servos acted as expected. As the throttle was advanced through it's range, all the other surfaces would deflect slightly and only momentarily, followed by the reboot and normal operation until the throttle was advanced again, and at the same point, the same action would repeat.

This was an odd circumstance that I don't believe was the RX's fault, and took a large amount of t/s'ing to isolate. The servo seemed to operate normally when operated independently, but I never used the servo. Couldn't trust it, knowing that 8 other servos were caused to operate erratically by this one servo...as soon as it was removed the glitch went away.

Just goes to to show what a bad servo can do, even on a modern radio system...

Best,

Chris

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