Spektrum DX7 Radio Failures : 3 crashes + 1 no response

[yellow_grey]

Hello All,

First post here in Helifreaks.. since most of the time, the search is very effective and covers most of the issues or opinions i would've asked about.

Anyways, posting on behalf of a friend's recently acquired DX7 and pretty disastrous results so far.

1st event: Non response from DX-7 tx using supplied rx in Nitro Heli. Problem resolved after rebinding. Worked OK with at least two flights before this.
2nd event: Electric Plane (balsa Zero) nose dive crash during low forward flight. Pilot complained of dead stick i.e. no response. This is using the DX6 supplied receiver AR-6000 i believe. Have been working before with the DX6 radio. Did one flight prior to crash with DX7
3rd event: Electric Wing (velocity) also nose dive crash after successful radio function checks on the same day. Plane equipped with another AR-6000 which used to be faultless on DX6
4th event: After crash (minor), same wing tested on the ground/ range checked, then attempted to fly again. Flew with control for the first few seconds, then again dead stick. Crash major this time - motor mount busted.

Any suggestions or experiences w.r.t dead sticks on the DX7 as so far i have heard great things about it.

Want to try rebinding to see if issue can be resolved, but pilot worried if problem persist during flight.

[ClayK]

The DX7 has problems? Say it ain't so.

[rwilabee]

Hello All,

First post here in Helifreaks.. since most of the time, the search is very effective and covers most of the issues or opinions i would've asked about.

Anyways, posting on behalf of a friend's recently acquired DX7 and pretty disastrous results so far.

1st event: Non response from DX-7 tx using supplied rx in Nitro Heli. Problem resolved after rebinding. Worked OK with at least two flights before this.
2nd event: Electric Plane (balsa Zero) nose dive crash during low forward flight. Pilot complained of dead stick i.e. no response. This is using the DX6 supplied receiver AR-6000 i believe. Have been working before with the DX6 radio. Did one flight prior to crash with DX7
3rd event: Electric Wing (velocity) also nose dive crash after successful radio function checks on the same day. Plane equipped with another AR-6000 which used to be faultless on DX6
4th event: After crash (minor), same wing tested on the ground/ range checked, then attempted to fly again. Flew with control for the first few seconds, then again dead stick. Crash major this time - motor mount busted.

Any suggestions or experiences w.r.t dead sticks on the DX7 as so far i have heard great things about it.

Want to try rebinding to see if issue can be resolved, but pilot worried if problem persist during flight.

I've flown my Raptor 90, Raptor 50 and my old Xcell 60 with no problems at all. No glitching or wierd things at all. Very responsive and range is as far as I can see the heli.

Rich

[RCHeliJim]

First off, why did your friend keep flying after the first crash event if he though the DX7 was at fault????

He very well could have a faulty unit, and after that first crash I would have sent it in for a checkup.

Like anything else, there will be units with QC problems. Have him send the radio and all the receivers in for a checkup so it can be determined what is at fault.

[Jermo]

Sounds like the Tx may have issues. What was the battery level of the TX each time and where there any other indications of abnormality?..ie difficult to bind, slow initialization..etc..

also tell us about the area you were flying in. Was it a flying field? a parking lot? Have you ever flown there before without problem? Is there a high power RF source anywhere near? Example: Radio Station, Cell Tower, Pager Tower, Microwave relay station..etc..

Regardless I'd report the issue and send it in for analysis/repair.
Jermo

[yellow_grey]

First off, why did your friend keep flying after the first crash event if he though the DX7 was at fault????

He very well could have a faulty unit, and after that first crash I would have sent it in for a checkup.

Like anything else, there will be units with QC problems. Have him send the radio and all the receivers in for a checkup so it can be determined what is at fault.

The first event, he thought it was simply pilot error or a busted servo leading to the nose dive. However rightfully said, he should've investigated thoroughly the crash prior to taking up another model in the air.

The odd thing was that he had successfully carried out a few flights prior without any issues. It could be possible that the problem may have surface till then.

Either way, he will be sending the unit back for a checkup

[yellow_grey]

Sounds like the Tx may have issues. What was the battery level of the TX each time and where there any other indications of abnormality?..ie difficult to bind, slow initialization..etc..

also tell us about the area you were flying in. Was it a flying field? a parking lot? Have you ever flown there before without problem? Is there a high power RF source anywhere near? Example: Radio Station, Cell Tower, Pager Tower, Microwave relay station..etc..

Regardless I'd report the issue and send it in for analysis/repair.
Jermo

Battery level is fine since he is using Li-Po's to power the TX as he did previously. However he did notice that binding took twice longer than his previous experience with the DX6.

W.r.t flying field, we have had no failures to date w.r.t DX6's. We have over 10 flyers using DSM DX6's and so far no crashes due to radio.

[Jermo]

<cut>Battery level is fine since he is using Li-Po's to power the TX as he did previously.

well my car is running fine since I put gas in it last week. It MUST be a broken car! :lol:

hehe..the type of battery used or the fact it has been used in the past doesn't answer the basic question. It's probably not related to the issue but it is best to ask the question and know 100% than assume.

looks like we're waiting for Spektrum to sort it all out.
Jermo

[MrMel]

Am I reading right, if I read that all crashes was with a AR6000 and not the AR7000.
Im too had the non-response before flight issue, but not to date any issues during flight.

[yellow_grey]

<cut>Battery level is fine since he is using Li-Po's to power the TX as he did previously.

well my car is running fine since I put gas in it last week. It MUST be a broken car! :lol:

hehe..the type of battery used or the fact it has been used in the past doesn't answer the basic question. It's probably not related to the issue but it is best to ask the question and know 100% than assume.

looks like we're waiting for Spektrum to sort it all out.
Jermo

Sorry if i'm not being specific enough, but he is using the same lipo pack he had used before in his DX6 (simply transferred it over after the upgrade) and yes, it had been fully charged and is in very good condition.

Another update.... we tried a range test sometime today standalone i.e. receiver, battery pack + servos, and found out that the link seems to be intermittent and did not occur immediately. After like a few minutes of on and off operation (i.e. playing around with the tx stick) we detected some non response events on the AR-6000. We have yet to try it with the AR-7000 receiver. Will keep you posted.

[fogger]

I have noticed at my field that when I turn on my DX6 Tx under the metal awning covering a couple benches the receivers in my models take longer to 'sync' to the Tx than normal. If I turn it on out from under the awning however the sync time is usually less than 3sec. I believe this to be due to some type of interference; there is a cell tower nearby.

So, when you notice it's taking too long to sync up, something is wrong, even if it eventually does sync up. It shouldn't take more than a 2-3 seconds IME. Sometimes mine sync in less than 1sec...

So, try powering down the Tx (-After- powering down the Rx of course), changing location/orientation, then turning it back on. Wait about 10-15 sec before turing on the Rx, so the Tx has time to scan and pick clean channels...

Good luck! ; please let us know what Horizon says.

-Fog

[spork]

I'm guessing that you're having multi-path problems when you fire up the TX under the awning. Basically, the TX is interfering with itself because some of the signal goes straight to the RX and some of it bounces off the awning and reaches the receiver out of phase with the primary path.

[kgfly]

Sounds like a faulty unit to me. Ideally your friend should send it all back to Horizon for service/repair/replacement.

BTW - There's no need to turn on the Spektrum Tx before the Rx. The Rx will output no signal at all on the throttle channel and stable signals on all other channels until it detects and locks on to it's bound Tx. Similarly, you can turn the Tx off first and the Rx will go to the failsafe setting on throttle and hold-last-position on all other channels.

This is quite different to legacy FM (PPM/PCM) radios where there is a risk (especially for PPM) of a the Rx spuriously decoding noise and generating random outputs or (PPM or PCM) receiving valid signal from someone else on your channel. This can be very dangerous.

For spread spectrum radios there is a 1-in-many-billion chance of noise or any other 2.4GHz signal source (which is all seen as noise) being decoded as a valid signal by the Rx and hence causing the Rx outputs to change. Another safety benefit of spread spectrum over FM :wink:

[spork]

For spread spectrum radios there is a 1-in-many-billion chance of noise or any other 2.4GHz signal source (which is all seen as noise) being decoded as a valid signal by the Rx and hence causing the Rx outputs to change. Another safety benefit of spread spectrum over FM :wink:

No question about it. Noise rejection is one of the truly great things about spread spectrum. But in my opinion it's important to understand and make the distinction (as I'm sure you do), between not decoding an invalid signal vs. always decoding the valid one.

Basically, spread spectrum technology is extremely good about avoiding false positives (it will not do something another radio or other source tells it to). But it's not impervious to noise in the sense that sufficient noise will affect it's ability to detect and decode it's own signal.

Don't get me wrong. I'm in no way arguing against spread spectrum technology. I'm not even saying that it's all just trade-offs. I think it's better - but like everything, it does have its limitation.

[yellow_grey]

My Friend's DX7 is returned and expected to be at the door by today. I'm curious to know what has been repaired/ or what the fault was. Will keep you guys posted once we receive the unit and carryout further range testing.

[fogger]

Kenneth Et-AL,

I believe, from my experience, that I can share with you that Ken's advice is partially inacurate.

Do -not- assume the failsafe throttle control position on your AR6000 Rx is set for no-throttle. I have personally seen a plane take off from a table at full throttle when it lost receiver signal, with the Tx on and throttle down. I believe this is because the receiver was not bound with the throttle in the off position. I believe it -may- have been set this way from the factory, but it wasn't my plane so I can't be sure. I do know that it was fine after we re-bound it correctly.

Please understand, whatever mode your radio is in and whatever position your sticks are in during binding -determines- what the Rx's failsafe positions are set to, and you should not assume Spektrum set the failsafe to no-throttle from the factory.

I once set the throttle failsafe on my 450 to about 80% ON-PURPOSE because I thought I was having momentary lockouts and I didn't want the heli dropping to the ground if it locked out for a second or two. (it turned out to be the ESC overheating) This resulted in a couple stripped main gears when I accidentally plugged in a battery before turning on the Tx. Live and learn.

So, always perform the binding proceedure with this in mind and never turn on a Rx before the TX is on and in a safe setting... Always bind your Rx, expecially on a brand new DX6 or DX7 with the failsafe control positions at a known setting.

Hope that helps :)

-Fog

[kgfly]

Fog - Good points.

It is up to the user to ensure proper binding and setting of the throttle failsafe level before ever connecting to a live model. I agree that for maximum safety, having the Tx on first/off last is a good idea, most especially if you still fly FM radios as well as Spektrum since you don't want to develop habits that put you in danger with your old gear.

[Ticidytoc]

It almost sounds like this thread needs to be renamed to "spektrum ar6000 rx failures"

I have 2 AR7000 and 1 AR6100 all of which work perfectly. The one pilot who has claimed a radio problem at my local field is using a AR6000 RX.

[Tommy Norman]

your not supposed to use the park flyer receiver with the dx-7 are you? couldnt that cause problems

[kgfly]

No, the DX7 will work perfectly well with all the Spektrum RX including the full-range AR7000 and the ParkFlyer AR6100 and AR6000.

[fogger]

My understanding is the DX7 is backwards compatible with the AR6000 (IE DSM-1)...

Quote from the horizon website:

DX6 owners, and anyone else who flies small electric models, will be pleased to know that the AR6000 receiver works perfectly with DX7 too. In fact, the AR6000 will actually benefit from the DX7’s signal speed, as well as ModelMatch and ServoSync. So whatever the aircraft in your collection, be it a .60-size heli or a 15-ounce foamie, you can fly it with the DX7

End quote.

Oh and from reading the the manual for my DX6 the other day it appears I was partially incorrect: the failsafe is set to 'last known good position' for all channels except throttle, and it doesn't say whether this can be changed by binding.

But it is clear that binding sets the throttle failsafe, so I was correct on that point at least :). Sorry for any misinformation in my last post.

-Fog