HoverOver

I just reported a major problem with my new Spektrum receivers (transmitter?). If after reading this post, I'm wondering if others are experiencing the same and if you've found resolution???

Anyway, here's my story - see if you can relate...

The SHORT Version:
Power cuts off (i.e. receiver shuts down) during flight. I have repeated the problem several times with two different Receivers in two different helicopters...
Transmitter: X9303
Helicopter / Receiver #1) T-Rex 450SE with AR7000
Helicopter / Receiver #2: T-Rex 600 CF (electric) with R921 receiver (came with X9303)
RESULT: Helicopters drop out of air with ZERO input control!!! Yesterday, the T-Rex 450 SE dropped from 25+feet during a climb-out. It landed on right skid with tremendous force breaking just about everything. This helicopter was PERFECT!!! I estimate $500+ in damage! I am not happy

The LONG Version (or at least the rest of the story):
My original thought was that it "could" have been the ESC cut-off setting as the battery was getting low. I am sure this was not the problem now, however, for several reasons:

• REASON #1) I use a low voltage warning alarm (on the 450 SE) which has an audible and visual warning system preventing me from running my batteries too low in the first place. It did NOT do this with my 7202 TX and R790 RX.

• REASON #2) It did the same thing on my T-Rex 600 (Brand new - just completed) which had a brand new fresh battery (thunder power 5000mAh) and freshly charged Align 1200mAh BEC battery powering the receiver. Fortunately I was only a few feet up and just hovering when it sent my 600 back to earth!!!!!!

• REASON #3) Yesterday it did it to my T-REX 450SE during flight when it had more than half of it's charge left (I verified this by re-charging my LiPo and documenting the amount of MaH's it took).

• REASON #4) Ironically, I was listening to the "All Things That Fly" pod-cast today (dated 10/22/07, Titled "ATTF #21 - It's your Canopy!") which can be downloaded from the following website: http://insideheli.libsyn.com/
I strongly recommend you listen to it starting at 35:00 minutes into the pod-cast. That is where they talk about what appears to be a similar, if not identical situation.

In any event, I recently sold ALL my old radio equipment in anticipation of the arrival of my X9303 / 2.4 GHZ stuff and spent a fortune!!! DID I MAKE THE WRONG DECISION? Who will pay for my T-Rex 450?

I'm a long time loyal customer but I'm gunna need some attention on this one - SOON!

John Clarke

You may have already did the following tests.

I would strongly suggest to put a WattMeter in line from the battery and the Heli. MAKE SURE THE HELI IS PROPERLY TIED DOWN!!

Move the servos one at a time and watch the Wattmeter. See if the amps go to say 500 MAH and return to zero after going to the max stick control position. If any servo goes to the full position and the wattmeter is not reurning to zero you have a overtravel problem or bad servo. Big trouble.

Now Move all the sticks rapidly. Watch the wattmeter to see what the current the servos are drawing (not motor running). Check the BEC rating and make sure it can handle the servo load. Most ESC'S BEC'S can only handle 1.5 to 2 amps for short burts and 3 servos.

Now spin up the motor. Watch for max draw. If the heli is say drawing 25 amps cont. and the battery is rated for 25 amps cont. (Think Hype about Continious amp draw from manufactures) you are drawing more than the actual max battery load and the voltage drops. You can get a RX dropout and reboot at perhaps 3.5 volts. Remember It only takes a few Milli seconds voltage drop to cause a reboot on the RX.

I hope you find the problem and if this helps great.

John F. Clarke
AMA 9473

Mac_Man_UK

Alternatively..... split your power supply. Feed the receiver with a standard NiCad, feed your servos from the regulator/BEC.

This way if it is a transient, then the receiver is protected.

HoverOver

Hi Fellas, thanks for your responses....

I do not use a separate BEC in the T-Rex 450 but do in the T-Rex 600. I suppose it is "possible that in a hard pullout (on the 450) the current drops enough to cause the rx to shut down - but then why did it do it when I was just hovering? More importantly, why it does it do it on the 600 which DOES have a separate power source for the rx (i.e. BEC). I understand the question and it would certainly be one of the first considerations but keep in mind I had the exact same setup but with the JR R790 RX with NO problems.

If I was sure it would prevent a "shut-down", I would invest into a separate BEC/power source (and add more weight) but I am not. I am seeing this problem more and more in these forums... I've considered the static issue but see that many people have taken all the grounding precautions from isolation, re-location and even letting their receivers "dangle" below the heli - all without conclusive results. I'm at a loss here. Did I get lured into something that is over-hyped here? Did I make a mistake? Have any more ideas?

I read through numerous forums and see references to the same kind of comments I am getting about the low power and static. I'm more of the mind that I am concerned with regards to why this would be happening with the AR7000 (and the R921) when it didn't happen with the JR R790 with the exact same setups (I did use a R790 in the 600 before I got the R921)... Seems like it might be a manufacturing / design flaw... I am trying to keep my emotions in check here because my true sentiments are lining up with the multitudes of other [disgruntled] Spektrum customers in the forums. I have this question posted in helifreak and runryder and am seeing some angry responses.

I'll let you know if I learn something but am anxious to see if someone else knows something.

Thanks, Mike

Redback

Interesting thought here about failsafe on the AR7000 and Helis (which I don't fly)

I have set mine to go to low throttle position on failsafe, which I suspect is the default for most. Seems to me that it would be really bad news for a helicopter to drop to minimum power under hold conditions.

Terry

HoverOver

Loosing power to your helicopter Receiver is NEVER a good thing. Loosing power AND control is even worse. The only place for the Heli to go is DOWN. The final analysis is: I need to think seriously about switching hobbies!!! I'm depressed!

onewasp

As one who started this hobby ---- back when a successful weekend was defined as one which left large enough pieces to allow you to glue them back together and be ready for the next weekend----I can tell you that there is hope!

Whatever the cause it can be ID'd and corrected.
Simply keep at it!
But thoughtfully so-------- Further attempts with the same set up will most likely bring the same results-------I'd start by looking at the ESC etc.

I have had the opposite experience with Spektrum----absolutely flawless------all kinds of weather, fields, A/C ----- though all were fixed wing.
However, I do not fly electrics or Heli's.

Since you do those are the areas of focus for corrections.

HoverOver

Wow! We've gone full circle here. One of the other forums in which I have posted has even suggested it is the gyro that is causing the phenomenon. I'm waiting for someone to suggest that it might be the paint job on my canopy!!! What is going on here???

By the way, if we were talking about loosing a few hours doing repairs on a bruised vehicle, I might not be so discouraged. But I have nearly $10,000 invested into this and at this point it is all worthless.

If you read through the forums, you will see that the common factor here is the Spektrum receiver... Period! There are descriptions of every conceivable configuration and setup, in every conceivable environmental setting - Cars, trucks, planes, helicopters, etc... They all seem to point to one thing: The Spektrum receivers for one reason or another will shut down... albeit at various levels of interactivity. And while I'll agree with you [Chris] that your problem seems to be an ESD issue, that is just the initiator in your case... It really isn't the problem (big picture). I propose the following theory (yes, there are gaps in this theory):

The receiver glitches - just like a 72mhz receiver would. But in the case of the Spektrum, because it has to "bind" with the TX. Since it doesn't see the Tx after the glitch occurs, it is simply instructed to shut down. Because the power supply is still on, it will sometimes re-power itself and re-bind spontaneously - and - sometimes it won't.

Final analysis: Spektrum has a major design flaw and needs to fix it ASAP (before someone gets killed). In the meantime, Horizon needs to offer a temporary solution to those of us who have invested into their "experiment" and have lost the ability to fly (Do you think I would even THINK of flying my brand new T-Rex 600 with this setup right now????). It is in their best interest to do this - lest many of us give up on the hobby all together and spend the money on other things like, uhhh, children's college educations.

Thanks for letting me rant!

arobatx

Hopefully Danny or other JR/Spektrum representatives will elaborate as they have certainly heard from and helped others that have experienced this problem, and loss as a result. After all, we're all chiming in here, and it's their forum!

Chad

onewasp

I understand the "rant" However Paul Beard IS a Heli guy!

Sorry to say (in you hour of need) but the Spektrum set up is neither new nor untested---quite the contrary it has gone through more than any radio should--------at the price $300's---- it is the least expensive radio I have EVER owned-----by a long shot!
AND at that price guess who got in on the act-------the inexperienced as well as the experienced RC'rs. THAT my friend would rigidly test any system at any time.

It has also been the LEAST trouble prone radio I've seen-----bar none!!!!
That statement covers the ground based five watt Tx set ups to today and everything in between.

It does require a different set pf procedures (very similar in end results to the change from Prop to Jet in full scale)----and yes I was around for that!

I've never seen a crash (we've got a bunch on DX7's, 9 and 10 channel modules as well) of any one of them----nor a bump, nor a glitch--------even the local Heli flyers like them------the electric guys too though they did some changing on ESC's/BEC's as some are fit for neither man nor beast.

It IS your set up, he says from afar-------!!!!!

BUT with the attitude you now exhibit (understandable though it may be) it just might be best to drop this hobby for awhile--------or go back to the buggy whip, because you are going no where with the IT'S THE RADIO---------because it is NOT------------- It is you set up!!!!!!!!!

You've got to get the information--------I saw it here on the web (several sites) regarding the ESC's and BEC's that did and didn't do well and the set ups. Can't lead you to it as neither electric nor Heli's interest me--------simply MY personal choice.
I had enough of Heli's in the U.S.Navy.

You are far from the only flier with YOUR Heli and a DX7------except the others are operating normally. Why?
----and again he says SET UP!

Now, that was MY rant.

HoverOver

I appreciate you checking my emotions. I want to keep the discussion about this issue.

I have a X9303 ($750) and two Spektrum Receivers (2 X $100+) in two Helis (One has external BEC & separate lipo receiver battery, the other with the BEC built into the ESC which gets it's power form the main battery) - The transient receiver failures occur on fresh (new) batteries under minimum load situations and stock setups. Both setups providing over 5volts to the receiver continuously.

When you say it IS my setup... what do you mean? Do you mean I need redundant BEC power supplies? I appreciate that your receivers work flawlessly (actually I am jealous) but as I pointed out in my previous rant, there appear to be multitudes of people experiencing similar problems.

Could it just be coincidence that I got two faulty receivers?

fizzwater2

My Feedback: (61)

perhaps it's the transient response of the regulator circuits in the BEC's..

DadsToysBG

My Feedback: (35)

None of us can figure out want happened over the net. Only you and Danny can do that. All I can add is look at the last heli fly-in at Muncie. 720 pilots only about 120 impounded on 72 and not one hint of a problem any where. No one waited for their channel, just pick up your heli and fly. I'll bet the guys on 72 weren't happy about that. Bet next year you'll see alot less of the 72. As a CD I just can't in my wildest dreams think about mangeing a impound with 720 radios.
To post no problems here would be a bore to read, and it would flood this forum. The answer is there in heli's look for it and correct it. Dennis

HoverOver

Hi Guys,
Just received an email back from Castle Creations. I had inquired about the CC Phoenix-35 I have in the T-Rex 450. His response seems to agree with the low-voltage theory. It still doesn't necessarily explain why the T-Rex 600 (with a separate BEC) is doing it as well. Here was his response (take special note of the word "ANY":

Mike,

The problem here is not with the Phoenix ESC but the Spektrum receiver. They have a know issue in that they shut down with almost any fluctuation with input voltage. When they turn back on, they have to rebind with the transmitter and usually a crash occurs within this interval. The onboard BEC design in ESCS has not changed in the last 10 years and in our case uses two linear regulators in parallel. The voltage from these is relatively stable but they can allow small voltage changes to the receiver under heavy servo load. There really is no reason why Spektrum receivers are sensitive to this; it is simply a design flaw. No other receiver is sensitive to these normal voltage changes. By the way, a regular MiMh receiver pack’s voltage supply is much more unstable than that from a linear regulator.

Currently the best solution for running Spektrum receivers is to disable the onboard BEC on the ESC by pulling the red wire between the ESC and receiver and use a separate switching regulator BEC such as the Castle BEC. Switching regulators are capable of supplying very close to constant voltage. This works around the internal voltage regulation design flaw in Spektrum receivers.


--
Bernie Wolfard
Product Support Supervisor
Castle Creations
235 S Kansas Ave
Olathe, KS 66061
913-390-6939 Ext 123

DadsToysBG

My Feedback: (35)

Well I'm glad you are gaining ground. but I question the word " flaw" in other words it's not our fault but theirs. I think his statement "not changed in 10 years' says much more. Maybe it's time for them to catch up with the times. If radio systems improve other companies must keep up. They are right in that the 72's could handle brown outs better. If they want to keep their market they will have to improve the product to meet the demands of the new radios. Dennis

HoverOver

Thanks Dennis.
I agree with the sentiments "It's not our fault, its theirs" is a common [poor] excuse (the computer industry is notorious for it). That being said, however, is creating a product that is more vulnerable to power fluctuations better or worse than last year's technology that wasn't?

Just food for thought.

arobatx

One thing it MIGHT do is somewhat 'force' those that previously didn't pay close attention to their power supplies and the respective demand for it, to do so. There have been so many advances in the strength of digital servos, brushless motors....etc, capable of drawing far more amps than what was available just a few short years ago, and yet I wonder how many folks actually have a watt/amp meter and have measured the current demanded BEFORE they have a problem and then do so reactively? I've only had one of these meters for about a year, and knowing what I do now, I wouldn't want to go back to a time without it. I have been surprised to see planes competing in IMAC, and the scary setups some have, without attention to detail in respect to power supply, unsatisfactory leads and connectors, and various RF interference issues. I for one would like to see the brown out issue addressed by JR and Spektrum, but I also appreciate all that is learned as a result of emerging technology in our hobby. We all benefit from it ultimately.

Chad

DadsToysBG

My Feedback: (35)

To make the receiver work in the planes it was necessary to add a chip to lock on to the GIID and the "two channels". This makes it react to low battery more so then 72. All of the 2.4 to the same thing. The speeds to hear from the different companies for reboot are all over the place, but they all have to reboot. Dennis

HoverOver

This forum thread has generated some very interesting discussion and I am genuinely impressed with the caliber of intelligent and thoughtful input!

Based on what I have read in all three forums I started with regards to this issue, I am concluding (at this point anyway) that it is a power fluctuation issue that is causing the spektrum receivers to shut down. The confusing issue to me was that 1) it appears that there are many different causes (i.e. low battery, too much current draw from servos, ESD, etc...) all with the same net result: a momentary drop in voltage and 2) I have a hard time with coincidences and with this happening to me in two different Helicopters with different setup configurations... well you know what I mean.

I had ordered one of the Spektrum voltage protectors (see here: http://www.*********.net/index.php?m...ducts_id=10718 )
and might consider trying this. For now, however, I have been invited to send my troubled parts including my broken bird) in to Horizon and they are going to run some bench tests and probably update the firmware, etc. I am grateful for their support and plan to update this thread with the results once I learn more.

Thanks again for all your help. I learned from you and hope to return the favor soon.
Respectfully, Mike

arobatx

This is good news, please do keep us updated on what you hear back from Horizon...we all want to know!

DadsToysBG

My Feedback: (35)

All of us have had to change the way we do things with the new radios. I for one have had to make major adjustment in my thinking with giant scale. The size of batteries, the load on the system, the amp. draw, the gauge of wire, the type of switches,cycling and testing batteries and the placement of receivers. What I don't have to worry about is the new guy not checking the board while I'm in the air or my gas engine giving the radio fits. All in all the radio systems with the new battery demands will make our planes safer and therefore the hobby safer. Dennis. PS Danny and his staff are the best. I know as a dealer I get to them more then most.

onewasp

{Quote}
Based on what I have read in all three forums I started with regards to this issue, I am concluding (at this point anyway) that it is a power fluctuation issue that is causing the spektrum receivers to shut down.

{Quote}

Unfortunately "a lot of talk and a lot of posts" is all that I have come up with.
There is a lot of assumption and VERY little data out there.

Can it happen YES-------the opposition loves this reference----specifics-----when I find the first one I'll let you know. Every 'lead' so far turns out to be the brother of a friend who knew his cousin who--------------------you get the drift.

Frankly that is a very convenient 'out'.
It MAY or may NOT be the answer to your circumstance---------GET THE FACTS !!!!
THEN make a judgment call for your situation.

The world has never seen the gross number of pseudo RF engineers this topic has unearthed.

Do NOT jump to conclusions------again ----GET THE FACTS !
THEN act.
So far there have been damn few who have.

Ed

"If you read through the forums, you will see that the common factor here is the Spektrum receiver... Period! There are descriptions of every conceivable configuration and setup, in every conceivable environmental setting - Cars, trucks, planes, helicopters, etc... They all seem to point to one thing: The Spektrum receivers for one reason or another will shut down... " - HoverOver



Yes, like all receivers they will shut down, if you reduce the voltage enough.
It always seems to be the people using electric's that are getting into trouble. [] ESC's, BEC's, and Regulators are causing a lot of people a lot of grief. Yet the people who don't use those items believe that Spektrum is the greatest thing since sliced bread. ( There has got to be a message there ! ) Giant scale fliers, Jet fliers, and other people with knowledge of power requirements, have no problems. It is the Users responsibility to provide the required working voltage to the receiver at all times. Fail to do this because of an inadequate power system, and you will pay the price.

If you need assurance as to what might be the 2.4GHz system of choice, go to RCU's Jet forums, and poke around a little bit. See what they are using, and how they are using it. I think that you will find the use of Spektrum/JR in those pricey jets overwhelming. I also think that you will find their power supply management a little bit different from yours. ( No offense intended , but it's homework time. )

" Spektrum receivers fail in flight!!!!!! " ? ? ? Naww. Like my friend Waspy up above, my five AR-7000's in Giant Scale aircraft, are rock solid glitch free performers.

> Jim

rgoldy

Being a member of the "club that doesn't exist" I am trying to figure out what happened so as to not repeat it. If you recognize the name you know the story: 30% Extra with digi's and a pair of 6V-2700mA batteries...
Anyway-lets throw this out for discussion-"rumor" has it that the standard 22ga servo connectors, that I am sure we all are using, are only capable of passing 3A. If that is true, I will be the first to say that I had all my power winding up running to 1 of these and into the Rx. Maybe that is an issue.
With that being said, I am also interested, why then did the person running a power box have an issue?

pedromvf

To all of you, I had a failure on my system and since I am between a beginner and an intermediate I only lost airplane (yep, not a heli flyer), engine and receiver (AR7000). In any case, since I work on a lab and have access to some special equipment I decided to do some tests. I put my servos (821) on a tray and connected them, using a piece of elastic rubber. In that way they would react against each other and I could test everything on a bench using an oscilloscope. The battery I used was the normal battery that came with the system (4.8V 1100mA) and the one involved in the previous accident. I did not charged it because I wanted to know what would happen. I played with the system and the battery voltage was never bellow 4.7V and I was scanning at 20 MHz, all the servos draining current at the same time.

With this, I think the voltage dropping bellow 3.5 volts hypothesis can be eliminated.

First Spektrum asked me to send the receiver, now they want the whole package. So, to finish the story, they want to me to pay another US$200 (transport from UK to USA and back) to have my radio checked.

If you want I can publish the e-mails I have sent to Spektrum about the subject and their answers. You will be surprised!