Spektrum SLT3 - Odd Behaviour, Has Steering But No Throttle

[PureChaosX]

OK, so I actually purchased this transmitter and receiver from an eBay seller who had removed it from his freshly purchased Big Rock, and since Arrma models come with these transmitters, I thought I'd try my luck finding some help here.

It was sold as "For Parts or Not Working" so no refund, but at the same time the seller was unsure whether he was doing anything wrong when it came to binding the transmitter and receiver. As it turns out, he may very well have been doing it correctly, as the something does feel faulty.

I have it binded to the SLR300 receiver no problems. Steering works no problem, as do the steering adjustments. Throttle however... is a literal no-go. There is no response from the throttle at all. When I turn on the ESC (HobbyWing QuicRun 1080) it blinks, usually indicating no transmitter signal, but steering does work. It appears that the transmitter is not sending any signal from the throttle, so the ESC doesn't initiate fully, except the steering.

I've tried calibrating the ESC, but since it's not receiving a "go" signal, calibration doesn't work. I've taken the transmitter apart (since I can't return it or get it replaced under warranty) and I can't see anything obvious. No components are damaged, burnt, missing (I think), the circuit board is undamaged, pretty much nothing out of the ordinary.

I know the trigger potentiometer works as I was able to test it on the steering, so the issue lies from the connector on the board to... where ever it goes after that.

Also, the ESC works fine with other receivers, and the SLR300 won't work with other speed controllers in other cars. I CAN get the throttle to work if I use the AUX buttons for forward and backward, but that's not really useful. So the ESC is definitely working with the receiver to some capacity, but the throttle channel is just... dead.

It COULD be the receiver I suppose, but I don't have any means of testing, without buying another receiver or transmitter.

So I've run out of ideas, after trying for a good 3-4 hours fault finding... I found no obvious faults. Google isn't very helpful as it just loves to omit the word "SLT3" a lot.

Does anyone have any clues? Any ideas? Any thoughts? Even a spare receiver you wish to get rid of. Any help is a good thing. Please and thank you!

EDIT: It works in my Tamiya Konghead and my Traxxas Rustler 4x4 VXL. It works in BOTH of those vehicles. They both use Traxxas ESC's. The Spektrum SLT3 refuses to work with all my other ESC's including Tamiya, HobbyWing 1060, HobbyWing 1080, HobbyWing MAX10 and an unknown branded one. Very strange.

EDIT 2: I made a YouTube video that goes a bit more in depth, as well as video demonstrations of what happens and how the transmitter and receiver behaves:

 

[SrC]

Calibrate the Tx to the ESC. Again. All I can think of. Then its a bad Rx.
Are you doing the ESC calibration procedure correctly? Sometimes you can end up in the ESC setting mode inadvertantly, when pressing the ESC SET button.
You gave much info and seem well versed.
Could just be the RX. Check polarity of the ESC plug to the Rx.?? All Wires etc.
IDK any further.


Edited.

 

[PureChaosX]

That is something I have tried, quite a few times actually. However, the ESC calibration just cancels itself because it's not receiving a signal from the transmitter (or receiver) in order to arm the motor.

The receiver works perfectly with my two Traxxas ESCs though, and I was able to calibrate each of those without a problem.

But everything has been checked, double checked and pretty much triple checked. It is possible it's the receiver, but doesn't fully explain why it's working with two Traxxas ESCs and none of my other ones.

 

[razorrc]

Does anyone have any clues? Any ideas? Any thoughts? Even a spare receiver you wish to get rid of. Any help is a good thing. Please and thank you!

EDIT: It works in my Tamiya Konghead and my Traxxas Rustler 4x4 VXL. It works in BOTH of those vehicles. They both use Traxxas ESC's. The Spektrum SLT3 refuses to work with all my other ESC's including Tamiya, HobbyWing 1060, HobbyWing 1080, HobbyWing MAX10 and an unknown branded one. Very strange.

EDIT 2: I made a YouTube video that goes a bit more in depth, as well as video demonstrations of what happens and how the transmitter and receiver behaves:

Make sure your radio throttle end points are set to maximum. There's a programming mode for the radio in the manual (turn on with steering full right, throttle full brake). Then you can max out your throttle end points.

 

[PureChaosX]

Make sure your radio throttle end points are set to maximum. There's a programming mode for the radio in the manual (turn on with steering full right, throttle full brake). Then you can max out your throttle end points.

Yep, already tried. In fact, it was one of the first things I attempted. I tried it several times but nothing happened. The ESC continued to act like there was no signal to arm the motor, like the receiver didn't even exist.

 

[razorrc]

My best guess is that the throttle trim knob potentiometer is bad and neutral throttle is off. Some ESCs are sensitive to what signal they expect for neutral and won't calibrate if it's not getting the right signal, some ESCs let you use anything for neutral.

You could mess around with the throttle trim at various positions to see if you can get the ESC to accept it (or allow you to calibrate).

I'm pretty sure the ESC sees a signal for throttle when you are trying to run/calibrate it (it works with your other ESCs), but it doesn't like the value it's getting.

 

[*420+3RC*]

Im having alot of the same with a Dx3 and a sr6110at. Im curious to see what happens

Exactly what my BR does. But sometimes I can get all way thru calibration but it will not save at the end. Then will randomly go full throttle

 

[PureChaosX]

The throttle pot seems to be OK, as far as I can tell, as it does what it's supposed to when connected to a Traxxas ESC. I have used contact cleaner on all the moving components though. When rotating the pot, absolutely nothing happens, not even a twitch of movement, LED blinking on the ESC in the same way if there was no receiver connected.

That's why it feels like the ESC isn't receiving the arm signal. The ESC is acting the same way as if it was switched on, but without the receiver connected. Almost as if the receiver didn't exist... but steering works, AND it works on the AUX CH3 channel, that uses the up/down momentary switches.

 

[razorrc]

The throttle pot seems to be OK, as far as I can tell, as it does what it's supposed to when connected to a Traxxas ESC. I have used contact cleaner on all the moving components though. When rotating the pot, absolutely nothing happens, not even a twitch of movement, LED blinking on the ESC in the same way if there was no receiver connected.

I'm not sure what you mean by "arming the motor". The HW ESC has a safety mechanism when you turn it on -- it expects the neutral value calibrated to it when you turn it on. If it doesn't get that, it locks out channel 2 rather than launch the car into a wall. Until it gets that programmed neutral value, it won't let you do anything with channel 2.

I think there's also a range it expects for neutral when you try to calibrate it. If it's too far off, it won't let you calibrate it. Not sure on this, but many ESCs have something like that.

That's why I think the neutral being sent to it is too far off from what it expects. Both when trying to run it, and while trying to calibrate it.

 

[PureChaosX]

The ESC needs to arm the motor... or initialize, if you will... once it's able to see the neutral position sent to it by the transmitter/receiver. Without the neutral position signal, the motor won't arm, or initialize, and as you say, locks out the CH2 controls.

I have in fact already watched that video, after I started searching for a possible answer to my problem. Both the trigger and throttle trim are in neutral, but the problem persists. I've tried multiple positions of the trim dial, turned it on and still the ESC won't initialize. It initializes with my Traxxas ESCs, even if the throttle trim isn't at neutral. There's something about the Traxxas ESCs that the SLT3 likes, yet hates about all my other ESCs.

 

[mob-1]

what battery r u using for the spectrum esc i have the same problem but only when using other batterys besides spectrum batterys

 

[bareracing]

What was the verdict here? Buy a new ESC? I am having same problem. String works, throttle does not. Get fast red blink when turn on. Can’t use set button. Don’t let Me calibrate. I have adjusted the throttle trim many times hoping I get it in neutral before start up.