Using a Spektrum DX3S and SR300 reciever with a Traxxas E-Revo

Spektrum DX3S transmitter

Spektrum DX3S transmitter

After unpacking, charging up the batteries and checking everything worked, the first thing I wanted to do with my new E-Revo was replace the radio gear. Don’t get me wrong – the transmitter and receiver that come with the model are fine, and I’ve not read any complaints about them, but since I bought a Spektrum DX3S for my touring car, I’d much rather use that.

The main benefit of using the DX3S is that it’s a 2.4GHz system – so it should have a greater range, and no risk of interference from other transmitters. There are other benefits too – it only needs 4 batteries, not 8, and since has a 10-model memory, I can set it up to work with the E-Revo and the T2R Pro straight away using the two receivers it came with, and by picking up another receiver I can  control the AX10 with it as well. I might even use it for the boat – one transmitter for all my non-flying models…

Anyway, the point of this post is to describe how I got everything set up to use the DX3S with the Traxxas E-Revo, so let’s crack on.

I’m choosing to use the SPM SR300 receiver in the E-Revo. You could use the SR3300T receiver which also comes with the DX3S, but as that is the one with the telemetry options I’ve put it in the Xray. The Spektrum receivers are nice and small, so should fit quite nicely.

2 - Note which wires are throttle and steering

1 - Open up the receiver box and note which wires are throttle and steering

The first thing we need to do is check everything works happily with the new receiver, so open up the receiver box and make a note of which wires go into which socket – two are for the steering servos (labelled CH1) and one is for the ESC (CH2). Fortunatly, the DX3S is a three-channel transmitter with matching receivers, so the presence of two steering servos isn’t a problem.

Next, you’ll need to trim off the tabs on the plugs so that they’ll fit into the Spektrum receiver. Use a sharp knife of a pair of snips, and be careful not to break the plugs. Once you’ve trimmed the plugs, fit one of the steering servo wires into the Aux port on the servo. On the DX3S transmitter, enable the Aux channel. Plug the batteries into the ESC and turn it on – now test that the steering works. If it does, you’ve successfully set up the second servo on the Aux channel.

2 - Check everything works

2 - Check it all works

Next, unplug the batteries, plug the throttle plug and the other steering servo into the throttle and steering ports on the receiver, and unplug the Aux servo. Turn on the transmitter, plug the batteries in to the ESC and turn on the ESC – blip the throttle trigger on the DX3S and the wheels should spin, turn the wheel and the steering should work (this proves that both steering channels are working, and you’re not just using the one). Next, disconnect the batteries, plug the Aux servo back in and you’ve got everything working. If anything hasn’t worked, check it’s all plugged in the right way around and in the right ports. If at any point you can’t turn on the ESC, chances are you’ve got a steering servo plugged in to the throttle port.

3 - Remove Traxxas receiver and replace with Spektrum receiver

3 - Remove Traxxas receiver and replace with Spektrum receiver

Next, you’ll need to remove the old receiver – first, loosen the screw you can get to on the cable-holding box alongside the receiver box. This is a neat little device that keeps the receiver box waterproof – the cable are fed through some foam inside it, which keeps moisture out. You’ll only need to undo the one screw, and then you can pull the aerial lead out from the receiver box. The 2.4GHz aerials are very short, so don’t bother trying to feed the new one through – it should be fine just tucked inside the receiver box. With the old aerial lead free, you can gently (but firmly) lever up the Traxxas receiver. Use a bit of servo tape on the new one to stick it in place, carefully replace the blue waterproofing ring around the edge of the box, and screw the top back into place.

That’s it – job done!