Axial SCX24 with injora emax servo problems

[msnyder1112]

Hello. I'm new to RC Crawlers and am running into an issue. I've searched quite a bit and cannot find an answer.
I have an SCX24 Gladiator. I recently put on Injora High Clearance track bars, Injora aluminium steering links and most recently the emax servo.

When I turn the car on, the servo turns right a hair and doesn't return. If I turn it on and off a few times it will be all the way at the right. I understand turning it on and off isn't normal behavior but I don't feel it should act this way.
Now when I turn the transmitter on, it does find center.

I've also noticed that when I'm on full lock on with the transmitter, I hear the servo still trying to turn. Is there a way to calibrate this?

 

[89Industries]

Yes. You need to reduce the dual rate (D/R on the stock scx24 controller I have).

This limits how far the servo will turn so it isn't trying to go through a hard stop or the steering linkage, etc.

The servo itself is kind of dumb. It really only knows it's own home position. So when you turn the controller on it's telling the servo all the needed information to make it work like you want.

If when you turn it on (with controller off) the servo horn is off to one side you can, and likely should, take the horn off and reinstall so it is as close to center as possible.

Then make sure the channel 1 trim knob is centered, then turn on the controller. This shouldn't matter the servo move. Then you can fine tune the center point using the ch1 trim knob on the controller to get it to drive straight.

Then the last thing you want to do is reduce the D/R so the servo stops before linkages and other parts hit hard stops. Check both directions.

If the servo D/R is set wrong and you get that constant running noise you will burn out your service pretty quick.

On better controllers you can set end points for the servo in each direction independently, instead of the D/R which just limits the overall angle equal in both directions.

 

[msnyder1112]

I don't think my controller has the D/R.
I only see SR (steering rate maybe?), ST(steering trim) then the other side has ST-R (steering reverse?) and THR-LIM (throttle limit?).

I can adjust the SR, but even at its lowest point, the servo seems to be wanting to keep running.

Maybe I'll just stick with the OE servo for now.

 

[89Industries]

That's weird.

Steering rate should be the same thingas D/R.

If you take the servo out of the truck but still hooked up to the receiver, so that the horn is just free to move without linkages attached does it still do continue to run at full lock?

Check your steering linkages for binding or excess friction while the servo is disconnected. Or does it do it while I'm the truck if you lift the truck up off the ground?

These little servos are not that strong. Doesn't take much to make them bind up. But I've had reasonable luck with the emax servos.

Could also be that you got a dud. They're cheap like that. I think I bought a 4 pack on Amazon or eBay for $30 or so but that was a couple years ago.

 

[msnyder1112]

i removed the horn and went left and right and it stopped when it was suppose to.
i'm not noticing anything binding when its all hooked up.

i did put the injora aluminium steering link on, but it was fine with the stock servo.

 

[89Industries]

Did the S/R knob change the amount the servo moves when the horn was removed?

Welp, I'm out of ideas. Hopefully one of the guys super into the 24s will have some good ideas.

24s were just my gateway drug into 1/10 scale stuff. Still have them, don't get abused nearly enough.

 

[racer15]

I've had similar issues with Emax servos on the SCX24. Even with no binding and SR turned down, they can still push too far and buzz at the end points. Powering on the radio before the truck sometimes prevents the initial twitch.

 

[msnyder1112]

Did the S/R knob change the amount the servo moves when the horn was removed?

Welp, I'm out of ideas. Hopefully one of the guys super into the 24s will have some good ideas.

24s were just my gateway drug into 1/10 scale stuff. Still have them, don't get abused nearly enough.

I disconnected the horn and the servo seemed to move ok.
I’m gonna return/replace and see if a new one is better.

 

[msnyder1112]

I've had similar issues with Emax servos on the SCX24. Even with no binding and SR turned down, they can still push too far and buzz at the end points. Powering on the radio before the truck sometimes prevents the initial twitch.

Did it ever prematurely burn up your servo? I hate that it does this.