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FLYSKY GT3b Transmitter

Old 01-09-2012, 10:13 AM
  #3196  
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Selling this if anyone is interested it's like new

http://www.rctech.net/forum/r-c-item...sky-2-4-a.html

THANKS
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Old 01-10-2012, 06:47 AM
  #3197  
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Default Receiver caught fire!

Anyone ever encountered this? Powered up my RX with a 2s Lifepo4 pack (which I have always used) to test some leds on ch3 and smoke and flames later

Nice scorch mark on the desk too!
Attached Thumbnails FLYSKY GT3b Transmitter-ptdc0065.jpg  
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Old 01-10-2012, 10:39 AM
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Originally Posted by nexxus
Anyone ever encountered this? Powered up my RX with a 2s Lifepo4 pack (which I have always used) to test some leds on ch3 and smoke and flames later

Nice scorch mark on the desk too!
See my below comment.

Originally Posted by elex300
I have to disagree on running 7.4v to the receiver. Eventhough the reading for the receiver says 6.6v it's not true. In both of my 1/10 and 1/12 pan cars we have to use receiver packs since we run on 1s lipo's. On the 10th scale I run a 2 cell life pack 3.3 per cell,which fully charged is 7.2v. In the 1/12 i run a 2s lipo rx pack 3.2v per cell and 8.4v at full charge. Been doing it for at least a year trouble free.
I'm glad it works! However, from a strictly engineering standpoint, the hardware may be 7.4v tolerant now, but we don't know for how long. Running electronics near or over the redline causes exponentially faster degredation of the parts. See nexxus' post above.

More then likely, the parts are 7v tolerant at the factory (not unusual), and 7.4 isn't a lot more of a push, so kudos to the manufacturer for designing an apparently robust piece of hardware. However, once a part does start to fail (which is why most electronics are run in the 50-80% of-maximum-rating regions), it's going to fail most spectacularly and with much fanfare when it finally goes, being run over or at maximum rating.

Whereas, a part run in the 80%-or-less region, will last it's typical MTBF (Mean Time Between Failure) which is typically a significant chunk of our lifespan.

Personally, I'm not going to push the limits of the hardware, even if it's only a 9-15$ part.
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Old 01-10-2012, 04:33 PM
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Originally Posted by WindDrake
See my below comment.



I'm glad it works! However, from a strictly engineering standpoint, the hardware may be 7.4v tolerant now, but we don't know for how long. Running electronics near or over the redline causes exponentially faster degredation of the parts. See nexxus' post above.

More then likely, the parts are 7v tolerant at the factory (not unusual), and 7.4 isn't a lot more of a push, so kudos to the manufacturer for designing an apparently robust piece of hardware. However, once a part does start to fail (which is why most electronics are run in the 50-80% of-maximum-rating regions), it's going to fail most spectacularly and with much fanfare when it finally goes, being run over or at maximum rating.

Whereas, a part run in the 80%-or-less region, will last it's typical MTBF (Mean Time Between Failure) which is typically a significant chunk of our lifespan.

Personally, I'm not going to push the limits of the hardware, even if it's only a 9-15$ part.
I can tell you beyond any doubt that receiver pack voltage had nothing to do with this. Most people run a 5 cell hump pack which is a nominal voltage of 6.0v, take one fresh off a charger and it's easily over 7 volts. A lifepo4 pack fresh off a charger will sit at 7 volts or less (3.5v/cell) and has a nominal voltage of 3.3v a cell (which is generous) I know my pack was at 6.3 volts total before I plugged it in.

It blew for some other reason, and while I appreciate you warning people against over volting a receiver, don't grasp at straws when trying to prove your point.
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Old 01-10-2012, 04:52 PM
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Originally Posted by nexxus
I can tell you beyond any doubt that receiver pack voltage had nothing to do with this. Most people run a 5 cell hump pack which is a nominal voltage of 6.0v, take one fresh off a charger and it's easily over 7 volts. A lifepo4 pack fresh off a charger will sit at 7 volts or less (3.5v/cell) and has a nominal voltage of 3.3v a cell (which is generous) I know my pack was at 6.3 volts total before I plugged it in.

It blew for some other reason, and while I appreciate you warning people against over volting a receiver, don't grasp at straws when trying to prove your point.
Grasping at straws is part of my job. I do SMD/Electronics Repair for a living, so a lot of this is just thinking out-loud. I'd have to go break open my 3-Ch reciever to do anything but, and I'm not exactly wanting to do work at home.

Point is, you're not doing what the mfg is telling you to, by heading up and over 6.6v. But I suppose that's part of the hobby.

Aside from that, c'mon. While I an appreciate your insistence that the battery wasn't at fault, the grasping-at-straws comment is a bit harsh, eh? I'm just going to assume that this being the internet and all, your intended tone was a lot lighter.
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Old 01-10-2012, 05:39 PM
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Originally Posted by WindDrake
See my below comment.



I'm glad it works! However, from a strictly engineering standpoint, the hardware may be 7.4v tolerant now, but we don't know for how long. Running electronics near or over the redline causes exponentially faster degredation of the parts. See nexxus' post above.

More then likely, the parts are 7v tolerant at the factory (not unusual), and 7.4 isn't a lot more of a push, so kudos to the manufacturer for designing an apparently robust piece of hardware. However, once a part does start to fail (which is why most electronics are run in the 50-80% of-maximum-rating regions), it's going to fail most spectacularly and with much fanfare when it finally goes, being run over or at maximum rating.

Whereas, a part run in the 80%-or-less region, will last it's typical MTBF (Mean Time Between Failure) which is typically a significant chunk of our lifespan.

Personally, I'm not going to push the limits of the hardware, even if it's only a 9-15$ part.
I too worked on small electronics for 10 years and you do have a valid point,and I probably would'nt do this if it was'nt a 10$ part to replace LOL Not to mention how many guys are pushing speedos and motors past there intended limit like you stated above. Not saying it's ok but it seems like the trend with this hobby. So I do have to agree with you there and I would hardly call your statement grasping at straws.
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Old 01-10-2012, 05:46 PM
  #3202  
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Default transmitter issue

Yesterday it worked fine. Today no steering control, just throttle. Re-bind, same condition. Try to bind with another flysky receiver, will not bind. I check the car with a traxxas tx and rx, all good.

I left both of my dvom's at work, but that did not deter me from doing a un-cased visual inspection of the connections and solder work. I am bench testing it with a known good esc, motor, servo and lipo(8 AA's in tx, even loaded 8 new to test, down to 10volts on screen).

All of a sudden, channel one returns, and channel 2....gone. Then channel 2 returns, but the neutral position is at half forward throttle. I could not get the mamba max to re-calibrate with the transmitter(mmp known good worked fine with traxxas tx/rx after that). At that point I went racing with my son, not using the fly-sky.

Any thoughts? This unit is two weeks old and still on the first set of batteries. thanks

jz
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Old 01-10-2012, 05:55 PM
  #3203  
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May be a looseantenna wire in the tx. Try having a look.
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Old 01-10-2012, 10:00 PM
  #3204  
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I'm letting my back up flysky go so if anybody wants it PM me. The radio is like new (back up) with maybe 5 runs on it. Comes with some upgrades.

- 2 receivers
- white led mod
- Voltage regulator mod
- Bearing for bearing mod is included
- Flipped polarizing screen, accidentally tore it, but it works fine still.

PM me if interested, 55 shipped.
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Old 01-11-2012, 04:25 AM
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@skyrider

if only you had posted this 2 days ago....

i just ordered a new radio from an eBay seller to replace my recently fried
GT3B !

Jason.
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Old 01-11-2012, 05:53 AM
  #3206  
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Has anyone found a way to soften up the spring tension on the trigger?
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Old 01-11-2012, 01:42 PM
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Originally Posted by elex300
Has anyone found a way to soften up the spring tension on the trigger?
Either swap out the spring or stretch out the standard spring.
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Old 01-11-2012, 08:43 PM
  #3208  
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By manufacture do you guys mean flysky? Or the actual vr manufacture that is used in the rx. Because i was looking awhile back trying to figure this out and i'm pretty sure this is the vr used

http://www.datasheetarchive.com/inde...DSA0041807.pdf

which has a max 12 volt input rating...which i haven't tried to push it this high BUT i run 2s lipo direct into my rx and it works just fine and i have at least 50 hours on it...
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Old 01-12-2012, 06:14 AM
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Huh, another Linear Regulator. Makes sense, low noise.

I think the problem you run into at that point is just a matter of heat. Linear regulators dispose of energy not used post-regulation (Ie. bleeding off the 2v difference between 8v and 6v) as heat. There's not a lot of current passing through this thing (0.3A), but higher voltage inputs start changing the heat curves almost exponentially, because with a linear regulator, the further away your input is from the output, the more heat it's putting off, as it has to dispose of the energy difference. The regulator is also fixed output, and I'm going to guess it's the 3.3v version, as that's pretty standard fare for logic IC's on the small scale, it also makes sense because FlySky says 6.6v input max (2x the regulator's output).

Again, not saying it won't work, because it obviously does. But it's kind of like standing on a fence, with bad balance. Eventually, you're going to fall.

In this case, the regulator is going to age, it's heat handling characteristics are going to change, and it's going to enter thermal runaway (More heat, lower resistance, more current, repeat.) And then lets the magic smoke out.
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Old 01-13-2012, 08:02 PM
  #3210  
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Hey guys, if anyone's interested in custom radio skins for your gt3b send me a email at [email protected]

Price will be about $45-50 + ship

and by custom i mean you can choose the design and have your name or username or whatever also on them.

I need have at least 15 people willing to pre-order.

There may also be a standard overkillrc version which will be 30-35 + ship
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