Throttle servo problem (I think) - please help

[dmj1977]

Hi All

so i bought a second hand brushless e-revo (the 1/10th one). I think its an older model (it has the TQ remote not the TQi). Apologies if I'm asking something obvious below but I've been reading around for a few hours and no joy.

Anyway, here's the problem. When driving it today, it stopped responding to the remote. I thought it might be the batteries being flat but new batteries made no difference. I've done some troubleshooting and it seems to me like something between the throttle servo and the receiver.

If I turn on the car (without turning on the remote) then the startup beeps play. The light on the ESC is yellow (with a slow flash on the green) and the light on the receiver (link) is red or flashing red.

If I turn on the remote and then the car, I get a bunch of different results. Most of the time I get no startup tone and often I get a red-light on the receiver. Sometimes a flashing a red light on the receiver and sometimes a red and green flashing light on the receiver. Sometimes I can get the wheels to turn in response to the steering on the remote but generally not the throttle. When the throttle does work it seems to only work intermittently and then it stops working. Also sometimes the throttle the flicks on for a split second even through no action is taken on the remote, similarly sometimes the steering moves even though no action on the remote. I can often get the steering to work.

However, if i unplug the throttle servo from the receiver then when I turn the car on I get the startup beeps. Further to that, if i separate the three wires in the throttle servo (orange, red, brown) and plug in any 1 of them on its own then the startup beeps play on startup. If I plug in the orange and brown wires the startup beeps play on startup. If I plug the red wire and either of the other wires with it then no startup beeps. (unless of course the remote is off and then any or all throttle servo wires being plugged in results in the startup beeps playing).

I'm at a loss as to what to try next. Any help would be gratefully received :-)

[dmj1977]

Oh, the throttle is plugged into channel 2.

[dmj1977]

(sorry for multiple posts). I've tried replacing the batteries in the remote, fully charging the batteries in the car, 2s and 3s batteries in the car, and re-pairing the remote and the car. I can't calibrate the esc as I can't get it to recognise that the throttle is held down when i turn the car on.

[87 GN]

I am not sure where you are at in trouble shoot'n,

can't calibrate the esc as I can't get it to recognise that the throttle is held down when i turn the car on.

Back up one step, the Radio & Rx are bound together, linked~up??
Next.......

Speed Control Programming Instructions

The Castle Creations Mamba Max speed control should not need
reprogramming with normal use. However, if you install a different
radio system in your model, or change the transmitter’s throttle-neutral
setting from 50/50 to 70/30, you will need to reprogram the speed
control. Follow these instructions to reprogram the speed control:
1. Install the batteries of your choice in the battery compartments and
plug the batteries into the speed control.
2. Switch on your transmitter.
3. Hold full throttle while you switch on the Mamba Monster controller.
After a few seconds, you will hear multiple tones and the
RED LED will light.
4. Hold full brake. After a few seconds, you will hear multiple tones
and the YELLOW LED will light.
5. Release the trigger to the neutral position. After a few seconds,
you will hear multiple tones and ALL THE LEDs will light.

[dmj1977]

Hey - thanks for the reply.

yes the Radio and Rx are bound / linked up (hold down set on controller till red light flashing, hold down link on Rx while turning on car, both lights turn green).

Sadly, I've tried the Speed Control Programming and when I get to step 3, I hold down the full throttle but no multiple tones :-(
(what happens with the lights seems to vary, sometimes flashing red, sometimes flashing green with red, i think flashing yellow once, but never steady red light, never multiple tones)

In case it matters, I should mention, the previous owner removed the on/off switch on the esc and left it wired to be permanently on (you connect both batteries, she powers up). So, step 3 for me is, hold full throttle while you connect the batteries). Don't think this would matter, but just in case...

thanks again. Any other ideas?

[87 GN]

yep that is ok not an uncomon thing bypassing the on/off switch.

you will need another set of hands, to plug in the batts as you hold full throttle on the radio, then go thru the steps
beep beep,

if that doesn't work, check the batts in the radio are charged, then prob time to call Castle.........

make sure the truck does not take off during programing..........
take off the tires, or unmesh the motor, or unhook the drive shafts.......safety first...

[dmj1977]

yeah, i've tried a bunch of times (gf not overly impressed with being called over to hold the throttle down, but she's doing it) :-)
No joy - gonna head to the local hobby shop and see what they can tell me.

thanks for the troubleshooting help :-)

edit (and yeah, replaced the batts earlier in the process)

[87 GN]

that is ok, gf not overly impressed

just throwing it out there un~plug the steering servo wires from the Rx, & try programing again......
maybe a bad servo............

[dmj1977]

yeah - you clearly know your stuff. I took it down to the hobby shop and they unplugged the steering servo and then the throttle servo worked again.
just in case anyone is ever reading this thread with a similar problem, apparently some traxxas stuff will act screwy when a servo goes. In my case the faulty steering servo caused all the problems listed above.

Thanks again for the troubleshooting help.

[87 GN]

Winner Winner chicken dinner..................lol

That seems to be happening more often...