Inherited HBX 3100a with issues

[AuburnVFR]

I’m a Newbie to the RC world, so forgive my lack of knowledge.
As the title states, I inherited a HBX 3100a truck with some issues and could use advice from the experts before blindly replacing more parts.

Issue: It does not consistently go into reverse. Most times, nothing happens when pushing the remote trigger forward (not confusing it with braking). Then after multiple attempts, it will reverse. It will continue at slow speed in reverse when the trigger is returned to neutral. Then reverse won’t work again. If the REV control switch on the remote is flipped, reverse works normally but now it does the same thing for forward.

My trouble shooting: It does the same thing when bound to a different remote. It does the same thing (using the steering wheel) when esc is plugged into steering servo slot on the receiver with no change. I tried a different esc with no change.

Bad motor? Bad receiver? If I replace the motor, should I get a motor/esc combo? Any recommendations for 2840 brushless 3800kv replacement? Are combo kit esc pre-programmed or will I have to program it?

thanks for any help

 

[CertifiedMike]

Welcome to RCTALK COM!!!

Glad to hear you inherited a problem!

Have you tried unplugging the servo and testing? Make sure its not gonna crash into the lamp on you!

 

[AuburnVFR]

I have not since there was no issue with steering function. I can certainly give it try though.

 

[CertifiedMike]

Curious what size and brand battery you have. How old?

 

[CertifiedMike]

If not these things, I'd look at a receiver based on your testing. I would not buy a combo. Flysky radios can be had on a budget and have good reviews.

 

[AuburnVFR]

Looked like the standard HBX issued batteries 1050mah 2s.. Also tried new Urgenex 1800 mah 2s to no avail.

 

[WickedFog]

Sounds like the receiver is glitching to me. Have you done a thorough inspection of the wires? Make sure to look at the servo lead connectores. Look at the female pins in them and make sure they haven't been damaged or pushed back. Take the receiver apart and look for dar spots on the circuit board. Try spraying everything with electrical contact cleaner and retest.

Another thing could be a bad antenna, or bad antenna placement. After taking the receiver apart, inspect the antenna solder joint at the board. They have been known to break loose in an RC where the antenna is not secured properly.

You mentioned having tried with a different transmitter. So you must have another receiver? If so, swap that in and see if that fixes it.

Sometimes a servo will seemingly work fine, but problems with the servo may cause the motor not to work. As Certified said, try disconnecting it.

One of these should find your problem. My bet is on the receiver, but it could be something else.

 

[AuburnVFR]

Unplugged servo-no change
Used receiver and tx from another car- no change

I guess it is time to look for a new motor unless you have another suggestion to try...

 

[CertifiedMike]

Check your wiring. This is prob the last thing I can recommend without having the in my hands to contemplate...
The only thing left IS the motor.

 

[WickedFog]

Unplugged servo-no change
Used receiver and tx from another car- no change

I guess it is time to look for a new motor unless you have another suggestion to try...

Wait a minute. Maybe I read into your first post too much, when you mentioned "nothing happens when pushing the remote trigger forward (not confusing it with braking)"

You do know you typically push the trigger forward to brake, then let it go back to neutral and push it forward again for reverse right?

There are usually three throttle settings in the ESC. Fwd/Brake only, as some race classes do not allow reverse. Pushing forward instantly applies braking.

Then you have Fwd/Rev, which is generally meant for crawlers. Going from pulling the trigger for forward movement instantly changes to reverse pushing the trigger forward.

Then you have FWD/Brake/Rev. Pushing the trigger forward while driving applies the brakes. To get reverse, the trigger has to return to neutral, then be pressed forward again.

Did you know that? That you have to double cluth the trigger to get reverse?

 

[WickedFog]

Can you upload a video to youtube and paste the link here?

 

[AuburnVFR]

Yes I know about the Fwd/brake/rev set up. I wanted to articulate that in my original post but “(not confusing it with braking)” was the best I could come up with.

I’m not sure about posting video as I don’t do social media or post stuff on YouTube.

At this point, I will probably just get a new motor/esc combo on Amazon since oem esc is only a 25a unit. More is better and so far this car hasn’t cost me anything.

Thanks for the help

 

[WickedFog]

Yes I know about the Fwd/brake/rev set up. I wanted to articulate that in my original post but “(not confusing it with braking)” was the best I could come up with.

I’m not sure about posting video as I don’t do social media or post stuff on YouTube.

At this point, I will probably just get a new motor/esc combo on Amazon since oem esc is only a 25a unit. More is better and so far this car hasn’t cost me anything.

Thanks for the help

Do you have an ohm meter?

If so, check the BEC voltage by checking the positive and negative pins on the receiver. See if you're getting what you are supposed to be getting. You can cut up a servo extension to make it easier to hook the meter up, then do some throttle blips and see what happens. It's really weird that it is only in reverse if it is the motor. So I am wondering if something isn't going on with the ESC.

 

[nino]

Uhhh... CALIBRATE THE ESC!!!1111oneoneone

 

[WickedFog]

Uhhh... CALIBRATE THE ESC!!!1111oneoneone

Oh geez. Did he not say he tried that? Hmm. I must be confusing this thread with another, because I could have sworn he said he tried that. I'll put my dunce hat on and go stand in the corner now

 

[CertifiedMike]

Would be happy and sad if this fixes it!

 

[AuburnVFR]

For the win…

Uhhh... CALIBRATE THE ESC!!!1111oneoneone

Did this (after finding instructions online) and everything appears to be working normally. I take it step one for trouble shooting random stop/go issues is recalibrating the throttle. Duly noted for the future.


Thanks all for the help.

 

[CertifiedMike]

NOW you can go buy the new motor, esc, etc...
Glad you got it running!!!

 

[Monk]

Hi, I just registered here to say thanks to everyone in this thread, just got a 3100a after not having an RC car for 25 odd years (figured I should try a cheap trophy truck before buying a yikong tb7) and was having the same issues, didn't know about the braking either just thought it was very unresponsive lol

So thanks a lot