Problems!! 14MZ 2.4 R6014FS

[Judge]

See this post:

http://www.flyinggiants.com/forums/443854-post62.html

He took a RX, placed it on a piece of black paper on his driveway. He covered that with the glass lid from a cooking pot to simulate the canopy and to trap heat.

He could not get his RXs to show this behavior.

[grayuk]

Yes, I saw that one but, I do not know if the rest of the gear was in sun or not.
If we assume it was not then maybe....there is a fault else where.
But, what is not clear is if the rx, in his case was enclosed all around (as it would be on an installation) or if just sitting on the paper with glass on top.
If that was the case then it is not a fair test of what is being described in the other failures. Air can move around too freely and remove heat.
I am not being negative here; I just want to be confident that this is a real problem.
I spend my life discovering and fixing issues in all manner of equipment, from military to medical.
It is critical to ensure that tests are definitive and not hiding another issue. (See the post on the vanilla ice cream!). It may be that this is actually an rx fault, if so, we can take measures to work around. But if it is not and we are all fooled, we are hiding another problem that will bite our ‘ass’ again when we least expect it. This is why Futaba will not ‘jump’ until they have had time to fully prove one way or another, then take the ‘right’ action.

I was once called to fix some medical equipment that failed on a regular basis, normally around 4 pm, but only on certain days and at certain times of the year! Strange but true (vanilla!) Other engineers had been in an failed to resolve the problem. Well after much head scratching I found the problem.
IA building opposite had a glass front, and at around 4pm in certain months, the sun was in the right position (but only if it was hot and the windows were open) light reflected into the room and onto the optical measurement sensors! This was enough to throw them out and give false readings! Now how weird is that?

Paul

[reyn3545]

If "breathing" holes were manufactured in the plastics, it would only allow the hotter to enter the case faster. Remember, the problem (at least in our minds) is not heat generated by the receiver, but ambient heat and its impact on the unit. Now.. breathing holes AND a fan... hmmm...

If no answer is found.. they'll be handing out flack jackets and helmets at the Tucson Shootout!!

In the same vane as your ice cream story... I used to sell PC equipment to BellSouth, a regional telecom provider in Atlanta. They opened up a new server room on one of the floors of the tower downtown, and once they got it up and running, they noticed that they were experiencing a high outage rate on the servers in this room. We had the PC manufacturer in several times to investigate possible power supply issues, electricians were in several times to look at available power, and I don't know how many people working on different aspects of the problem. Then, as Bellsouth was putting together a list of all recorded failures, someone noticed that they seemed to peak around noon and 5:00, and only on weekdays.... Yep, by now you've guessed it... the brainiacs decided to put this server closet right next to the elevator banks, and there were eletrical surges with the elevator activity during peak times. I don't know if they were pulling power from those circuits, or if it was some other technical thing above the comprehension of a sales guy, but as soon as they relocated the server closet, the problems went away.

[grayuk]

I am sure breather holes would help.
From what we have been told the rx generates quite a lot of heat on its own.
Normally this heat dissipates well as the ambient air is much lower in temperature. It does this through conduction.
As the ambient temp increases the temperature gradient between the RX and the surrounding air reduces, this means that the rate of heat dissipation reduces, so the rx gets hotter.
The rx will always be hotter than the surrounding air because it is a heat source. What changes is its ability to dissipate that heat into the surrounding environment which is now very hot and can only remove heat slowly from the rx.
If we can introduce a convection path (holes on the underside an don the top), the air can move through the case and take heat with it, dissipating the heat much more efficiently.

Your point on the server, seen similar things with soldering machines! These were putting massive spikes on the mains and screwing up computers!

[martin18152]

He took a RX, placed it on a piece of black paper on his driveway. He covered that with the glass lid from a cooking pot to simulate the canopy and to trap heat.

He could not get his RXs to show this behavior.



This is why the problem is more complicated than just the case temperature. As I stated before, electronic temperature profiles are complicated, and require engineering evaluation. The receiver may have to be under load, and under certain installation conditions etc…

I also don’t understand the Hitec Issue, if you read the directions that come with the Hitec programmer, it states that their digital servos operate on a control voltage from .8 to 5 volts , so what dose 2.7 v have to do with the problem. Looks like compatibility problem not defined.

I can say one thing; my first experience with futaba service was pretty good. I sent in a 3 year old 14mz radio with a failed trim switch, they fixed the switch, did a lot of other stuff, and as far as I can tell, no charge. I’m just waiting for the radio to be sent back.

[grayuk]

I am running a jet on 10 channels using a 14 channel rx.
A 12FG TX all servos are Hitec.
I have no issues, all work perfectly.

Paul

[gregorycstitt]

Maybe they should be handing out flack jackets and helmets now. It doesn't have to be a big show for someone to get hurt. My plane was taxing back rolling on its own when I lost signal. Thank God it was rolling slow or at least slow enough I could run up behind the plane and shut the ignition off. Remember guys, is doesn't have to be a TOC show for someone to get hurt. These radios and receivers are used by average fun flyers like myself everyday.

[grayuk]

Sorry to be a pain again but how many independent failures like this have been documented?
Are they all in the giant scale type?
Has any one reported a failure in a different type of aircraft?
Paul

[Judge]

	Quote: Originally Posted by grayuk
	Yes, I saw that one but, I do not know if the rest of the gear was in sun or not. If we assume it was not then maybe....there is a fault else where. But, what is not clear is if the rx, in his case was enclosed all around (as it would be on an installation) or if just sitting on the paper with glass on top. If that was the case then it is not a fair test of what is being described in the other failures. Air can move around too freely and remove heat.

Well, it is at least as fair as hitting it with a heat gun as another person did.

	Quote:
	I am not being negative here; I just want to be confident that this is a real problem.

As do I and I am waiting for Futaba to determine if it is indeed a problem or not.

But it amuses me to no end that the Internet mobs will take the word of people whom they have never met and know virtually nothing about over the word of the manufacturer. All this because they think Futaba is going to lie to them or whatever

[fastford]

	Quote: Originally Posted by martin18152
	I use to work in the military electronics business years ago, and there were all sorts of ESS programs to test thermal / vibration environments, these tests were done on 100% production units, at various sub assemblies. The trick was to pick test parameters that sufficiently stressed the component / assemblies, with out degrading its useful life. I doubt Futaba dose ESS on a 100% basis, you probably could not afford the product if they did. I would hope they do some, on a sampling plan, but who knows. I will bet they are probably doing a little right now. Some times big problems are connected to the simplest fix, that’s engineering, and I’m sure Futaba is working on it. Thermal profiles are very complicated, and I wouldn’t try to guess the problem. Simple thermal profiles show a linear decrease in temperature from the high T1 to low T2; however, the rate of heat transfer in nonlinear and very complicated. In this case you have a lot going on, radiation from the sun, radiating heat out of the receiver, internal generated heat by components, convective air over the case, and some heat generated convective air inside the case. You could eliminate the sun radiation by putting the receiver under some balsa or by using non insulating shield, that would eliminate one complication and would not hurt; however, heat transfer will stop once T1 = T2 regardless of the sun radiation, if T1 is your internal heat generator, it will continue to rise in temperature until T1 > T2 and energy will then continue to transfer from T1 to T2. Since the heat generated in the unit is fairly low in frequency, the rate of heat transfer out of the case by radiation is probably insignificant, where on the other hand the frequency of heat generated by the sun is very high, and the transfer rate is very significant into the unit – for this reason, it confuses me on why futaba makes their cases black, unless they plan on the units being in a dark place (classically that’s the way it use to be prior to the giant scale revolution with huge canapés) , then emissivity would dictate energy to flow out of the receiver by radiation. The amount of energy transfer is dependant on the geometry of the conducting / radiating surface. Energy can be transferred along board traces to the buss, and out through the servo control wiring. Once again the power box, or power distribution system would help, buy reducing the current through the receiver buss, therefore increasing the heat transfer. This is my opinion, and I plan on doing the following to make me feel better, since I have no direct knowledge of the problem, and I have not had any problem with my present system: Do not put the receive in direct sun light under the canapé, you can put it in the fuse, I doubt balsa and covering will block 2.5 GHz signals - maybe not the case with carbon fiber fuselage. Use some sort of power distribution system that reduces the load to the receiver buss If you have to put the receiver in sunlight, reflecting shield the receiver with a non insulating cover, that allows airflow over the receiver. Cover the canapé while it sits on the flight line, this should be done regardless of your receiver, I have seen canapés warp / melt on sunny hot days, so most people do this anyhow. Do a prolonged ground check prior to flying; chances are if heat is the problem, it will show up on the ground before you fly. I can say this will work with full canisters exposed to the inside of the fuse. Have Futaba hire more Mechanical engineers, thay are better a thermal dynamics than electrical engineers, lol, just kidding. If futaba has a design problem and it sounds like there me be some undefined issue, wait for futaba to better Idiot proof their system, and still do all of the above.

Mark I am impressed

[fastford]

edit

[freya1]

Judge, nobody is trying to discredit Futaba, we fly futaba since I can remember and will continue to fly Futaba because I am sure they will find a solution.
I know you weren" there and you can think whatever you wan't, but I saw it happen as did a few more people at the field, and as you can read it has happenned to people in other states as well.
My equipment has worked with out issues even on the same day it happenned to my friend, but should I push my luck untill we know exactly what is going on? I think not! I like to bring my kids to the flying field and so do my friends and I am not risking their lives because you think we are lying, Maybe Futaba had a bad batch of receivers and only those will be affected, but somebody needs to do some testing or investigating instead of saying we are lyers because you don"t know who we are.
We ara not trying to create a panic or bash the product, we just want to bring the issue out so it can be fixed before somebody gets hurt.
Thank you

[emessys]

	Quote: Originally Posted by Leardriver
	Well for what it is worth I was able to duplicate the original problem almost down to a degree of what Lazun originally reported with both a R6014FS AND a R607FS rx on the bench just a little while ago. I used a heat gun and a Raytec IR temp gun to measure temp as it increased. Within a degree of each other they both "went red" at 167-168 degrees. I was able to "reboot" them around 150 deg. Both these rx are brand new (a few weeks) and were still in the box. I bound the R607FS just for the test. The flip side of this is that the 6-7-8ch receivers have been out now for a while and I don't remember hearing anything at all regarding any type of loss of signal in the air. Maybe it happened but I don't remember hearing about it(except for the service bulletin issued by Futaba some 6-7ch tx having the same coding or ID). I am honestly thinking that there is enough air flow through the fuse that the rx should be cooler in flight than on the ground. I am thinking about getting a Venom temp gauge like we used to use in heli's to record the peak temp on the rx. I am also thinking about how I can increase cooling to the rx. Perhaps a CPU fan and some sort of ducting for outside air to be channeled over the rx. I am not sure yet. Now for those that are getting ready to say go get Spectrum...not so FAAST (couldn't help myself here...lol). A friend of mine, who is in the R/C electronics business, has actually disassembled and examined the spectrum satellite rx and taken the information right off the the chip and found per the manufacturers spec on their very own website that the chip is only rated Commercial (not industrial) and is good up to 70C or 158deg F. He has mentioned that customers have called him and mentioned the they have had a lockout or binding issue with the Spectrum setup but could not duplicate it. It is possible that they are suffering from a thermal issue as the Futaba is. Here are the specs on the Spectrum chip he sent me. By the way..I am not trying to bash JR, just trying to pass on some info that may be helpful. The guys at Spektrum use this chip CYRF6936-40LFXC in every satellite receiver they sell. This is a commercial temperature range chip, 0C-70C. See page 31 of the data sheet attached. -------------------------------------------------------------------- ------------------------------

We'll, if you could get hold of some Thermal Compound and a piece of Aluminum plate, you might try rerunning your tests with the RX sitting on the plate (with compound between the plate and the bottom of the RX) to see if the still RX craps out at the same temp.

It might advance the state of knowledge while waiting for Futaba.

Of course, a big metal heatsink in the vicinity of the 2.4Ghz antennas might not provide a flight solution.

It is possible that the component/components that are quitting are part of a bad run and the design is not at fault, or it could be that the combination of ambient temp/radiated temp absorption and internally generated heat (probably from the processor) go beyond the design limits of the RX.

I imagine some heavy duty processing is occuring to handle all those channels plus the frequency hopping algorithms etc. Thats gotta generate a lot more heat than simpler receivers (I think), assuming the same type semiconductor technology is being used.

Ira

[1bwana1]

I don't think anyone is calling people who are reporting this problem liars. OK, maybe Judge is, but they pay him well in free "T" shirts to call you names. He must have a very large collection by now. Don't freak Malvey, I'm just kidding!

Bill, from Futaba, has taken the time to post that Futaba is aware of, and is looking into, the issue. They are not calling anyone a liar, and appear to be treating the issue seriously. I'm sure Bill will let us know as soon as Futaba has an "Official" response. In the mean time, it will be up to each of us to decide whether we feel safe in flying this system or not. I can understand those who have seen the problem first hand, being the most reluctant to fly with the system.

I hope people continue to experiment, and contribute their findings to this forum. Despite the brand warriors, that somehow always end up injecting themselves into what should be a useful exploration of technical issues, discussion like this often add significantly to our knowledge base. From my perspective, it is likely that something is going on with this system, the sooner we find out what it is, and how to deal with it, the better off we will all be.

[Leardriver]

	Quote: Originally Posted by Judge
	Well, it is at least as fair as hitting it with a heat gun as another person did. [COLOR=black][FONT=Tahoma]

The way you make it sound it was completely recklace and basically has no merit. Well all I did was find a way to raise the temp of the case of the receivers (read different brand new rx's!) to the reported temp in a controlled environment (on the bench) with no load and a regulated 5 volt battery. No servos. When the cases hit 167 deg on the first rx (R6014FS) it went red and would not reset until it cooled to approx 145 deg. The second rx (R607FS) did the exact same thing with 1 degree! That is exactly what the other four receivers in in the original post did...yes I spoke with them directly.

Now Judge, if you think there is an issue with trying to duplicate what has been reported than I do not know what to say. I am a Futaba supporter. I love my 12Z, it is in my opinion the best radio I have ever laid my hands on. But, I will not jeopordize my $7000 worth of 40% airplane (not to mention the liability/safety issue) if I have ANY doubts about the equipment in it! The test I performed was simple and controlled (to the best of my ability). What does it prove...we'll see. Futaba is aware of a "potential" issue and is working on it. I know that in a very short period of time the temps are gonna be in the 80-90 degree range wich means the inside of the plane could easily reach 150-160 degrees in the heat of the day. Yes we cover them...yada, yada. But the potential risk (read liability) is not worth the chance if there is doubt. By the way, the claims of an issue ARE coming form credible sources. I also know of a helicopter pilot that put his heli in the sun with the canopy on ....10 minutes later the rx went red.

To date my equipment has performed flawlessly. Absolutely perfect. But now comes the Joe Nall fly-in that I am leaving for in 11 days. It should be 80-90 degrees. The planes sit on the flight line in the sun waiting to fly. I believe there is a potential for the plane to heat up enough to "possibly" reach the ambient temps guys have reported earlier in the thread. Will there be a solution or suggestion from Futaba by than? Maybe. If not, do we "go for it" and see what happens? go back to 72mh for the event even though half the event is now 2.4 only? I am going to install a Venom Racing temp meter in the plane on the rx to record the actual temp things heat up to in flight. I truthfully believe they run cooler in the air but honestly to this point don't know.

The sky is not falling and this will get sorted out. It appears that nobody has lost a plane to this "issue" yet and we need to keep it that way. We do need to wait and see what the engineers come up with but vigilance is in order. This is not a "rumor" and is a repeatable event. I know the formula and can reproduce the failure at will. Will it happen in the air..I am honestly not sure. Is that grounds to go fly it...uh..well. If the ambient temp is 70 like it as been here on the east coast prob just fine. 80-90.....I am less inclined to do it until we have more information. I don't think what I did to check the receivers was invalid at all. Why don't you try it yourself Judge and see what happens? Hey, if it doesn't fail than it may prove that this IS more random than it appears. That would be a good thing.

If I misread or misinterpreted your comment than I apologize for the "retort", but it does appear you have a little bit of skepticism regarding this issue and it's kinda like discrediting those that have brought it to light. I may be reading too much into it but it is just the way it is coming across to me. I am all about the orange jersey. but things do come up from time to time with everything.

Ok, enough said..guess we'll have to wait and see how this lays out.

PaulP