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Want to instantly fry your Novak GTB Spread Spectrum?

Want to instantly fry your Novak GTB Spread Spectrum?

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Old 01-29-2008, 12:30 PM
  #61  
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Originally Posted by TeQ View Post
Jim,

The first GTB I popped it was on Lipo Cutoff, but the battery was fully charged regardless. The second time, it was just the stock settings.

The DS1015 is the same servo that all the Team drivers for Associated run in their B44's. It's made by ACE/Thunder Tiger. This is what I wanted to run in my B44, so I got it. To call it off brand or cheap is pretty silly, perhaps just ignorant.

Peace!
I never called it off brand or cheap. So please don't make it sound like I did. I only race Touring car. Not offroad. So I'm not familiar with what servo's the offroaders run. The specs do look pretty good. Ton's of torque. Just looking for why you are having this kind of trouble with your esc and I haven't. Just trying to help....
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Old 01-29-2008, 12:38 PM
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Jim,

That wasn't intended for you.

Everyone else,

I believe there are 4 people reporting experiencing this problem with GTB SS and so far only 2 people that are sure they have one that works fine. So I would consider that mounting evidence.. which is the point off this thread in the first place.

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Old 01-29-2008, 01:36 PM
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The servo wired up backward should have no effect on the esc if the esc is turned off. Unless somehow the esc has a faulty circuit on the on/off switch.
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Old 01-29-2008, 05:27 PM
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Originally Posted by Turbo Joe View Post
Everyone has their cross to bear.

I know that there are people out there that use Ace servos...and I know that there are other name-brand servos made there. There's just nothing special about them and nothing that makes them magically super-efficient enough to blow up a speed control. Motors just don't work that way, even if they are in an uber-cool Ace servo.

On the motor thing...if you really think they have different motors in each servo...then how would you explain the fact that when you looks at the specs for servos in the same family (say 359/360 Airtronics)...one gets more torque and slower, while the other gets more speed and loses torque?

If they really had a faster motor for this one and a slower/toque-biased one for that one...why would it be slower? If you think that each one has been uniquely designed...you haven't been around much manufacturing...LOL Lesse...the torque one would need this controller...the speed one..that...different motors...more different components...or just do it with gears and call it good.

Two guys who blew up GTBs is not "mounting evidence". I ate Doritos once and then I got a bad flu...and threw them up. If that ever happened to anyone else, there would then be "mounting evidence" that Doritos cause the flu and nausea.


http://en.wikipedia.org/wiki/Correla...mply_causation

Didn't eat Doritos for a long time after that...but they didn't really make me sick.

Again...I'm ready and willing to try out any other reasonable theories you guys can think up.

Nobody said that the Ace servo is any more uber cool than any other. Just that it is not an off brand as you have referred to it.

I feel very confident that the Air servos in the same family do use the same motor and they get their different results using gearing. I never denied that or even tried to imply that possibility. That being said, do you think the Ace servo uses the same motor as the Airtroincs servo? I have no idea. For that matter do you think all the premium servos use the same motor regardless of brand? Once again, I have no idea what motors they use. Maybe the Ace servo has a very inefficient motor inside. It uses way more electricity to turn. I have no idea, but I bet you don't either.

Now, just because you and somebody else are not having a problem doesn't mean the problem does not exist. Maybe it is operator error. The problem doesn't have to happen every time to every person in order for there to be a problem.
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Old 01-29-2008, 06:37 PM
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Yes, I do think they use the same motors for different servos...if the name brand places do it, the knock-off places aren't exactly the ones to go the extra mile. That's not in their business model.

And yes...he was implying that since he had such a trick servo, it would somehow be feeding back more (insert some relevant electronic unit here) to the ESC to make it burn up. That's nonsense for at least a couple reasons...one because a high-output motor would be a pretty low output generator...they work differently...and two...because moving the wheels back and forth isn't exactly an uncommon activity for R/C cars.

He obviously has a problem somewhere...but it's far from obvious that it has anything at all to do with the ESC...and far more likely that it has to do with operator error or a bad servo.
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Old 01-29-2008, 10:29 PM
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The info he was relaying regarding the the high power and higher power draw was not something he just made up. Might be a total load of garbage, but in the sales description of the servo it is described that way. I will provide a link. Doesn't make it true, but it isn't just some guy coming on here making stuff up to try and impress you.

http://www.amainhobbies.com/product_...oducts_id/5733

If you would climb down from your high horse long enough, maybe some people would be able to benefit from your knowledge. How you say things can be just as important as what you say. The servo might have an issue, but how would you explain that the servo supposedly works just fine with other ESC units?
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Old 01-29-2008, 11:45 PM
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I think pretty much any halfway sophisticated person realizes that it's hard to convey emotion or personality in the written form on a web board. I'm not trying to be a dick...I'm not a dick...but come on...some of this stuff is really basic electronics stuff. Motors are lousy generators. That's not new. A powerful motor makes an even worse generator...again...not a new idea...not something I just made up.

I'm not even saying that it's not the ESC...or that you can't blow it up with some voltage under some bizarre condition or another...but if you really want to believe that a tiny trickle of current can blow up a GTB...then you've gotta explain why it doesn't happen to everyone with a GTB, rather than one or two guys. If it's some systemic issue with the GTB...it's gonna happen a lot, because there are a lot of them around and none that I've seen have blown up from turning the wheels. Hell...I have a lot of them and I do it all the time.

FYI -- all digital servos draw more power. They hold center better because they have a faster duty cycle. The speed control inside is more powerful, not the motor. When it's not "on"...it's not drawing anything.
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Old 01-30-2008, 01:50 AM
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Now you are just talking.... Much better thanks.. I know that motors do not make great generators, but they are capable of making electricty otherwise we wouldn't have any brakes on the electric cars.

I know why the digitals draw more power. Most have a duty cycle 3x that of the analog servos. That is why the hold their position much better. They "check" their position 3x as often.

You seem to be fairly certain that the servo is causing the ESC to blow up. If the servo were shorted, why does it work with other speedos. I am no electrical expert, but if it were shorted I wouldn't think it be generating any electricity. Even if the servo isn't shorted, by your own words it shouldn't be able to generate enough electricity to damage the speedo. Shorted it wouldn't make more electricity, would it?

I am anxious for somebody to figure out what is damaging these things.
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Old 01-30-2008, 02:03 AM
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It's either a short in the servo or he has the ESC battery leads reversed. That's what I think at least. I've been wrong before and I'm sure it will happen many more times in the future, but I don't think I'm wrong this time.

Do really believe that a few milliamps is going to destroy an ESC...or at least the BEC...that's built to handle 5 amps? Really?

I don't care if it's making any electricity or not...it's not going to make enough to smoke the ESC. There would be smoked GTBs everywhere...every time a car was set up or connected or touched. I would have smoked mine the other night...

Originally Posted by Scott Fisher View Post
Now you are just talking.... Much better thanks.. I know that motors do not make great generators, but they are capable of making electricty otherwise we wouldn't have any brakes on the electric cars.

I know why the digitals draw more power. Most have a duty cycle 3x that of the analog servos. That is why the hold their position much better. They "check" their position 3x as often.

You seem to be fairly certain that the servo is causing the ESC to blow up. If the servo were shorted, why does it work with other speedos. I am no electrical expert, but if it were shorted I wouldn't think it be generating any electricity. Even if the servo isn't shorted, by your own words it shouldn't be able to generate enough electricity to damage the speedo. Shorted it wouldn't make more electricity, would it?

I am anxious for somebody to figure out what is damaging these things.

Last edited by Turbo Joe; 01-30-2008 at 03:06 AM.
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Old 01-30-2008, 04:35 AM
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fyi the speedo we had go up was the NE3032 brushless system which comes pre-wired and with tamiya connector, this was replaced by a deans ultra and raced the previous monday night. on the next sunday the driver was doing his setup checks, battery was connected but the speedo switch off.went to remove front wheels(why i dont no) and the steering was turned not by much i understand and his speedo started to make a crackling sound and then produced enough smoke he lost visibility of the car! he removed the battery connector, reconnected after a minute or so and tried the unit no power and started to smoke again.i dont think he was using a high output servo. still waiting to here from cml the importers in the uk. i dont think it matters what servo is used, it is for some reason frying the internals of a speedo that was used twice. the fault is with the units( probably a certain batch with a faulty component) only novak no what happens and will they say, probably not. so the debate continues with opinions be used to the max.
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Old 01-30-2008, 05:39 AM
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Do these new digital servos have a PCB inside? Maybe they have some type of capacitor or something, that retains some power LOL. Then upon movement of the servo horn releases all is stored energy, backfeeding the Rx to the BEC circuit. Smoke.
It could happen.
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Old 01-30-2008, 07:39 AM
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Originally Posted by Turbo Joe View Post
It's either a short in the servo or he has the ESC battery leads reversed. That's what I think at least. I've been wrong before and I'm sure it will happen many more times in the future, but I don't think I'm wrong this time.

Do really believe that a few milliamps is going to destroy an ESC...or at least the BEC...that's built to handle 5 amps? Really?

I don't care if it's making any electricity or not...it's not going to make enough to smoke the ESC. There would be smoked GTBs everywhere...every time a car was set up or connected or touched. I would have smoked mine the other night...
Allow me to clarify the final points you are still trying to make. The car ran fine, if the car ran, it's not possible the battery is reversed polarity.

The servo ran fine before the ESC blew up and it now runs fine in my 8ight. I've connected my voltmeter to the servo and there is clearly no short. Regardless it wouldn't turn my 8ight like butter if the servo had a short. I have had a short servo before and my RX popped as a result. (this was a whole other setup, just results I've experienced)

So either a) I'm a liar and made all this up or b) there is something wrong with the ESC's when they get voltage on the back end if the ESC is off and the main battery is connected. - Perhaps the same thing would happen if you connected a RX pack to the RX while the Battery pack is connected to the ESC? I don't know because I don't have any working GTB's and I'm going to leave that to Novak to determine. I do know the Spread Spectrum is based on a whole new design for Novak and there is high potential a problem like this exists.

Your point has been made. You don't believe I know what I'm doing. That's ok, you don't know me! However, instead of attempting to shoot down every point I make, just sit back. I assure you there is a problem and we'll soon know exactly what it is.

Regardless I will video the next attempt if Novak chooses to simply send me a replacement. I will record every step I've described and we'll have our evidence. I'm tempted to just go out and buy another one in the meantime to prove my point.

Peace
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Old 01-30-2008, 08:05 AM
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Originally Posted by Turbo Joe View Post
It's either a short in the servo or he has the ESC battery leads reversed. That's what I think at least. I've been wrong before and I'm sure it will happen many more times in the future, but I don't think I'm wrong this time.

Do really believe that a few milliamps is going to destroy an ESC...or at least the BEC...that's built to handle 5 amps? Really?

I don't care if it's making any electricity or not...it's not going to make enough to smoke the ESC. There would be smoked GTBs everywhere...every time a car was set up or connected or touched. I would have smoked mine the other night...
Hi Joe, lets get some points clear first.

1.We reversed the battery leads,well that would be a dead short circuit on the battery causing? yep massive current flow in what 1 to 2 seconds the esc would be a moulten blob, so my esc was sat there for up to 5 mins battery connected correctly. BATTERY NOT CONNECTED REVERSE POLARITY

2. A short circuit on the servo please see above massive current flow and most likely receiver goes phut! my servo is now currently working with my spare GTB no problem (except I will not move the steering servo for fear of repeat performance).NO SHORT ON THE SERVO.

3. Servo like you said will generate a back voltage, now we have a reduction gearbox in the mix as this provides the torque and will also move the servo motor rapidly when moved manually.

4.As has been said earlier its not what you say but how you say it and as you put it you are not trying to be a dick but it does not come over like that.

Yours a reasonably sophisticated person.
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Old 01-30-2008, 10:46 AM
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Often it's the act of disagreement that makes you a "dick". There's so much nonsense and magical thinking on these boards...and when you attempt to refute someone's deeply held belief, you can do it in the nicest possible way and you're still a dick. If you really believe that the Sun circles the Earth, there's not a way I can tell you it doesn't...that doesn't make me a dick.

Why not measure the current? Voltage without current is nothing...lesse what the mighty Ace servo makes for current.

I moved mine full sweep as fast as I possibly could...I was doing it like I was Les Schwab trying to make a fire. I'm sure there IS a problem somewhere...but I'm also really sure that your theory about how it happens is not grounded in reality. Hell...you could have just gotten a bad ESC. Yeah...a bad ESC...LOL...it happens. I blew up my first one and I wasn't touching it...just pulled the trigger and "POOF". I could have started a thread with the same title and come up with a theory that the 2.4Ghz throttle signal would vibrate the board and cause a short.

FYI -- "brakes" in a DC motor have nothing to do with back EMF, It's not a regenerative function. How do you suppose that brakes still work when the car's not moving? They work similar to reverse, only when you're moving forward, you reverse the voltage to the motor (BR) or change the order of the phases (BR) so that you have the rotor being pulled in opposite directions at once.

Oh yeah....on the "voltage comes from the servo" thing...so...all the voltage won't turn on the receiver? If the servo makes voltage, it's in parallel with the servo. I know that a Spektrum needs ~3v and a few hundred mA...a standard one would react faster, but a Spektrum will failsafe pretty quickly.

Since you have a meter and you say you know how to use it, why not measure the current your Ace makes? I'll measure mine here and that should tell you pretty quickly whether you have a special servo that can make lots of current.
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Old 01-30-2008, 01:40 PM
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Hey Joe,

This is more constructive for me.

Can you elaborate on your theory with the RX? The RX is inline, but as you know the light only comes on once it's synced with the TX.

Remember I've blown two GTB's in a row, not just one and made an assumption. The second one that popped I specifically expected it to when I turned the wheels. Both times though the car ran fine and was fully functional prior to this.

In the two cases I've used different Spektrum Recievers. I'm assuming you are also using Spektrum? It's possible it may be servo/rx related as well, I suppose.

Please clarify, you have the SS GTB? Not just the GTB?

I'm not convinced that it is the servo current that caused the problem, I just took a guess on that one. I'll measure it and find out though once I find something that will provide some resistance to properly measure it.

Peace
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