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Matt888

esc or receiver faulty?

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I bought a new 2.4 ghz transmitter and receiver a couple of weeks ago, I finally got around to fitting it and last weekend took it for a bit of a spin,

Anyway all was well the car was going nicely but the grass was a bit long and the esc got a little warm and the car shut down. I let the car cool down then just stuck to the tarmac and all was well.

The next day I decided that the beach was the place to go, at first all was still well then a couple of doughnuts later the Scorcher just shut down again, this time not because the esc had overheated it was hardly warm but it was beeping as if the tx and rx had unbinded themselves.

I switched the car off and back on again and the rx came back to life so off I went again same thing a couple of doughnuts and it shut down again repeated process but this time when I accelerated away and let the power off the car kept going for a few seconds before slowing down.

I packed up a came home, last night I had a check around the car for loose wiring and decided to try again with the car on the bench everything was perfect, I took it into the street accelerated and the same thing happened again the car ran away for a few seconds.

My Transmitter is a Etronix et1100, Reciever Etronix et1155 and esc is Tamiya TEU-104BK.

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What voltage is your receiver rated to handle?

The 104BK has no BEC, and supplies the full drive battery voltage to the RX, which can cause trouble if it isn't rated to take it.

See here:

https://www.tamiyausa.com/product/item.php?product-id=45041

Before I fitted this I was told to fit a ubec in the power cable between the esc and receiver which I have done to drop the volts to max 5.5v

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Ah, so it won't be that then, unless of course the UBEC is faulty.

You mentioned that the car "ran away" for a few seconds. During this time, did the steering respond, or was the car ignoring you completely?

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Ah, so it won't be that then, unless of course the UBEC is faulty.

You mentioned that the car "ran away" for a few seconds. During this time, did the steering respond, or was the car ignoring you completely?

From what I recall it did steer as it did a doughnut.

What is confusing me is the esc beeping as if the rx had shut down and no green light on the rx until I switch the car power switch off then on again, I didn't have to bind them but I did after about the third time of it happening.

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Right, so let's think this through:

Scenario 1

The ESC is faulty, and is ignoring the signal from the RX, which is working fine. The ESC beeps because it thinks it is getting no signal. However the RX is still working normally, hence steering remains functional. But this doesn't explain the lack of a green light on the RX, or the need to rebind.

Scenario 2

The ESC is fine, but the RX is faulty and not sending it a signal, so the ESC lets the car run for a couple of seconds while it tries to figure out what is going on, then switches to failsafe mode, shuts power to the motor and beeps in protest. This may explain the throttle behaviour, but doesn't explain how you retained steering control.

Scenario 3

Only one channel on the RX is faulty - the one connected to the ESC. As with scenario 2, the signal to the ESC drops out, so the ESC switches to failsafe after a short delay, and beeps to tell you of its woes. Steering control is retained as the steering channel still works, for now. The fault affecting the throttle channel also affects the green LED, and possibly the RX ability to retain binding info when turned off.

Scenario 4

The ESC and RX are fine, but the UBEC is faulty. As it warms up, it either supplies too much or too little power to the RX, confusing the poor thing and causing it to send the odd burst of unintelligible gobbledygook to the ESC and servo. The ESC, being a relatively intelligent piece of kit, takes a few seconds to try to make sense of things, then gives up and goes into failsafe mode. The servo on the other hand, being quite dumb by comparison, maybe twitches a bit but keeps following orders, so you retain a reasonable degree of steering control. However the RX soon gets totally confused, turns off its light and possibly forgets its binding info, until you reset the system and the UBEC behaves itself again. This scenario explains all the observed behaviours, but seems rather unlikely - UBECs are usually quite reliable, and if they break, they usually stay broken - a reset seldom helps to restore normal function.

On the whole, I am leaning towards scenario 3 - a partially faulty RX. What do you think?

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I must say even though I'm not too clued up on it, I my gut feeling was that the rx was faulty, because it seems to have two faults that are different but both point to the rx.

I just wanted to be sure before I take it back to Antics that the esc wasn't getting upset because it had a 7.4v LiPo powering it.

Also I'll stick a multimeter on the ubec just to check the output voltage.

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For what it's worth, I had a very similar scenario with a Kyosho 2.4ghz rx and a Tamiya TEU-101BK...the car would "run away" for a few seconds but still retained steering control. The ESC would shut down and would flash until I turned it off and then on again. At the time, however I was using a 6 cell NiMh battery and no BEC... I was told that it was a partially faulty rx with a channel that is 'shorting out' I replaced the rx with a Spektrum and so far, no issues.

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Good points so far. On another note, please make sure the short aerial of the RX is able to extend all the way out. It may also be worth checking if the wire is broken or has loose contact to the RX's PCB.

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A bit of an update I took the car to Antics where I got the tx and rx from drove it around the shop for a while and nothing no problems with the car at all. I was just about to leave with my tail between my legs and I said I'll have one more go luckily I did as it shot across the shop into the rifle stand and unbinded.

The manager then decided that the rx was faulty and swapped it over, took it home, that evening took it to Longwell Green BMX track for a bash and perfect the best it's ever run then about 25 mins in and disaster it ran away for a second and unbinded, I packed up and headed home.

Today I charged the battery again and headed back to the BMX track for another bash and again the car ran like a dream, again after about 25 mins the car this time didn't run away but did stop and unbind.

I'm sort of thinking that maybe the ESC is getting hot as it is in the plastic casing with no ventilation and shutting down?

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With a 2.4GHz set, binding is a 2-way process. Basically, during binding the receiver and transmitter swap details and mutually agree to communicate only with each other.

So, if binding breaks down, and the RX has been replaced to no avail, this suggests that the TX might be involved?

I suppose it could be the ESC causing the car to stop, but while I have had issues with ESCs in the past, none have ever caused the RX and TX to unbind. Has anyone else ever experienced this phenomenon?

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With a 2.4GHz set, binding is a 2-way process. Basically, during binding the receiver and transmitter swap details and mutually agree to communicate only with each other.

So, if binding breaks down, and the RX has been replaced to no avail, this suggests that the TX might be involved?

I suppose it could be the ESC causing the car to stop, but while I have had issues with ESCs in the past, none have ever caused the RX and TX to unbind. Has anyone else ever experienced this phenomenon?

The reason I think it's the esc is because that's what is powering the rx and my thought was that when it gets hot and shuts down it shuts down the power to the rx and that's why it loses it's bind.

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I can see the logic in that, however if your RX was losing its bind due to lack of power from the ESC, surely it would also lose its bind when the car was powered off after each run, or when changing the battery?

I suppose it wouldn't hurt to try though. Do you have a spare ESC, or anyone local who could let you borrow one for testing?

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I can see the logic in that, however if your RX was losing its bind due to lack of power from the ESC, surely it would also lose its bind when the car was powered off after each run, or when changing the battery?

I suppose it wouldn't hurt to try though. Do you have a spare ESC, or anyone local who could let you borrow one for testing?

Ah I see what you are saying, I have ordered another brushless esc and motor combo because I wanted to put one in the Scorcher anyway, so it should be here in a couple of days so I'll fit it in and give it a try.

https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=42936

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With a 2.4GHz set, binding is a 2-way process. Basically, during binding the receiver and transmitter swap details and mutually agree to communicate only with each other.

So, if binding breaks down, and the RX has been replaced to no avail, this suggests that the TX might be involved?

I suppose it could be the ESC causing the car to stop, but while I have had issues with ESCs in the past, none have ever caused the RX and TX to unbind. Has anyone else ever experienced this phenomenon?

2.4GHz systems don't have two way communication unless they're telemetry equipped AFAIK.

So what happens during binding is that the transmitter sends its code out on a fixed channel and the receiver listens to that.

I think that most transmitters only have a fixed code, but more expensive ones may have separate codes for each model memory.

I've tested this with cheap Flysky transmitters (FS-GT2E, an Eurgle rebadge) and I can bind multiple receivers and still use each without rebinding. I believe someone did the same test on a Spektrum system as well.

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A bit of an update I took the car to Antics where I got the tx and rx from drove it around the shop for a while and nothing no problems with the car at all. I was just about to leave with my tail between my legs and I said I'll have one more go luckily I did as it shot across the shop into the rifle stand and unbinded.

The manager then decided that the rx was faulty and swapped it over, took it home, that evening took it to Longwell Green BMX track for a bash and perfect the best it's ever run then about 25 mins in and disaster it ran away for a second and unbinded, I packed up and headed home.

Today I charged the battery again and headed back to the BMX track for another bash and again the car ran like a dream, again after about 25 mins the car this time didn't run away but did stop and unbind.

I'm sort of thinking that maybe the ESC is getting hot as it is in the plastic casing with no ventilation and shutting down?

Are you actually going through the binding process each time? Or does the car come back to life with a fresh pack?

It almost sounds to me as the receiver is just cutting out as the voltage drops.

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Are you actually going through the binding process each time? Or does the car come back to life with a fresh pack?

It almost sounds to me as the receiver is just cutting out as the voltage drops.

At first I was rebinding the car as per the instructions but then I found that if I unplugged the battery and plugged it back in it would reconnect itself, but that's when it would start running away constantly and the RX would keep shutting down.

But if the battery was low on charge wouldn't the LiPo alarm go off?

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2.4GHz systems don't have two way communication unless they're telemetry equipped AFAIK.

So what happens during binding is that the transmitter sends its code out on a fixed channel and the receiver listens to that.

Copied and pasted directly from the Spektrum SR300 manual:

"Its important to understand that during the binding process the receiver not only learns the GUID (code) of the transmitter but the transmitter learns and stores the type of receiver that its bound to."

That is why, when I fully reset a model profile on my TX, the RX previously bound to that profile is no longer bound to it, even though I haven't reset anything on the RX end. I need to rebind the TX and RX for normal function to resume. This in turn suggests that if the OP is still experiencing binding issues with a new RX, the issue may lie at the TX end.

That said, there may indeed be something up with the ESC and/or UBEC concerning their supply of power to the RX, as indicated by the following text, also copied and pasted from the abovementioned manual:

"When using multiple high-current draw servos with an inadequate battery/power source, heavy momentary loads can cause the voltage to dip below this 3.5-volt threshold thus causing the entire system (servos and receiver) to brown out. When the voltage drops below the low voltage threshold (3.5 volts), the receiver must reboot."

My only serious reservation about this explanation is that the OP reports retaining steering control when the car "runs away". If the RX had browned out and was rebooting, this would affect throttle and steering, not just throttle.

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My only serious reservation about this explanation is that the OP reports retaining steering control when the car "runs away". If the RX had browned out and was rebooting, this would affect throttle and steering, not just throttle.

The only reason I thought that the steering was working is because it ran off and did a 180 spin the first time it happened, it happens so fast that I haven't been able to see if I can get it to steer again it's usually hit something or shut down before my reflexes can kick in, so I would think that you are probably right about it browning out, I've got a new esc coming with built in Bec so I'll fit it and give it a whirl and hope that sorts it.

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Copied and pasted directly from the Spektrum SR300 manual:

"Its important to understand that during the binding process the receiver not only learns the GUID (code) of the transmitter but the transmitter learns and stores the type of receiver that its bound to."

That is why, when I fully reset a model profile on my TX, the RX previously bound to that profile is no longer bound to it, even though I haven't reset anything on the RX end. I need to rebind the TX and RX for normal function to resume. This in turn suggests that if the OP is still experiencing binding issues with a new RX, the issue may lie at the TX end.

That said, there may indeed be something up with the ESC and/or UBEC concerning their supply of power to the RX, as indicated by the following text, also copied and pasted from the abovementioned manual:

"When using multiple high-current draw servos with an inadequate battery/power source, heavy momentary loads can cause the voltage to dip below this 3.5-volt threshold thus causing the entire system (servos and receiver) to brown out. When the voltage drops below the low voltage threshold (3.5 volts), the receiver must reboot."

My only serious reservation about this explanation is that the OP reports retaining steering control when the car "runs away". If the RX had browned out and was rebooting, this would affect throttle and steering, not just throttle.

Interesting.

I haven't bound anything to a Spektrum in a while. Don't you set the type of receiver or at least type of transmission before binding? That is what you do with the FlySky and I also belive with Sanwa. I still have a feeling that the transmitter is storing the given transmission protocol (written as "type of receiver" in the manual) along with the code and not actually getting any signal from the receiver, but I may be mistaken. And different brands may have different methods.

Anyway, back on topic; good luck with the new receiver Matt888. Do you have a separate LiPo Alarm now? The TEU-104BK has neither LiPo cutoff nor LiPo alarm built in.

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