SCX10 III 2 speed transmission issue

[JennyBudew]

Hey everyone, I hope this is the right place to ask this lol, if it isn't then please move my thread to the appropriate area. With that out of the way, I was wondering if anyone could help me with my SCX10 III, any help is greatly appreciated - allow me to get into it:

About a month after I got it, a strange issue with it has started happening. It starts up just fine, but the micro servo that controls the 2 speed transmission will start twitching all by itself. After a few minutes of run time, the car will stop and refuse to move. Everything else still works fine (like the steering) but it won't move. At this point, changing the transmission from low to high gear works, but it sounds off. If I turn off the car, unplug the battery, and leave it alone for a few hours and then come back to it, it'll start up just fine as if nothing was wrong (it'll move and everything) but then of course after a few minutes we're back to step 1 lol.

I've taken a short video to help show what's wrong with it. Here's the link:
https://www.youtube.com/watch?v=hAU3s-4sn5s

(Just to clarify, the second half of the video is me pressing on the throttle to show that it isn't working)

Edit: here's the electronics in the car
Holmes Hobbies 550 trail master Expert 21T

Full aluminum brushless waterproof JX 46kg servo

Hobbywing WP1080 ESC

Tactic TTX300 3 channel transmitter

TacticTR326 HV receiver

Thank you for reading

 

[$uicide $hift]

For the micro servo twitching what model are you using? If the micro servo has a max voltage of 6.0V and you are running 7.4 or higher it could be burning out that servo. The servo you listed I assume is for the steering and not the 2 speed transmission?

I don't believe this would cause the rig to not be able to drive forward but I could be wrong. You state this problem goes away if you let it sit for a few hours with everything unplugged. Once you plug it back in and run it about how long before you see the issue appear again? Have you touched the motor and ESC to see if they are hot to the touch?

It could also be an issue with the transmitter. I have had odd issues like this where my radio has a monitor that I can check the position of the controls as I activate them. I would notice with the monitor the signal was jumping all over the place. Calibrating the controls on my transmitter fixed it but I don't think your transmitter has this feature.

Do you have another transmitter you can try out to narrow down what component is causing the issue? If you do and the issue is gone you know it is transmitter related. If it has the same issue with a different transmitter then I would start looking at the receiver. Do you have extra components that you can swap out to help narrow down which component needs to be looked into deeper?

 

[JatoTheRipper]

Welcome to the site! I moved it to the SCX10 III section because it will get more views there.

One of the electronic components seems to be glitching. Do you have another ESC and receiver to try to rule those out?

 

[JennyBudew]

For the micro servo twitching what model are you using? If the micro servo has a max voltage of 6.0V and you are running 7.4 or higher it could be burning out that servo. The servo you listed I assume is for the steering and not the 2 speed transmission?

I don't believe this would cause the rig to not be able to drive forward but I could be wrong. You state this problem goes away if you let it sit for a few hours with everything unplugged. Once you plug it back in and run it about how long before you see the issue appear again? Have you touched the motor and ESC to see if they are hot to the touch?

It could also be an issue with the transmitter. I have had odd issues like this where my radio has a monitor that I can check the position of the controls as I activate them. I would notice with the monitor the signal was jumping all over the place. Calibrating the controls on my transmitter fixed it but I don't think your transmitter has this feature.

Do you have another transmitter you can try out to narrow down what component is causing the issue? If you do and the issue is gone you know it is transmitter related. If it has the same issue with a different transmitter then I would start looking at the receiver. Do you have extra components that you can swap out to help narrow down which component needs to be looked into deeper?

This is the micro servo i'm using (at least, they look exactly the same lol)
https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMSSX107

the servo I listed is for the steering btw, usually when I plug it back in and it works again the issue will reappear anywhere between 5-20 minutes later. The ESC and Motor aren't hot when I touch them. I plugged in a spare reciever and transmitter but the micro servo still twitches and the movement problem is still there. I don't have a spare ESC to use, sadly. I wish I could find out what voltage that micro servo uses but the description on the site is blank lol

Edit: I found the servo's page on horizon hobby and I found this: Servo Operating Voltage:4.8 - 6.0V

Oh I also forgot to mention, the batteries i'm using have a voltage of 7.4 and 11.1

 

[$uicide $hift]

This is the micro servo i'm using (at least, they look exactly the same lol)
https://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMSSX107

the servo I listed is for the steering btw, usually when I plug it back in and it works again the issue will reappear anywhere between 5-20 minutes later. The ESC and Motor aren't hot when I touch them. I plugged in a spare reciever and transmitter but the micro servo still twitches and the movement problem is still there. I don't have a spare ESC to use, sadly. I wish I could find out what voltage that micro servo uses but the description on the site is blank lol

Edit: I found the servo's page on horizon hobby and I found this: Servo Operating Voltage:4.8 - 6.0V

Oh I also forgot to mention, the batteries i'm using have a voltage of 7.4 and 11.1

Do you have the programming card to the HW 1080 ESC? The voltage that is sent to the receiver is set by the ESC. Can you check what the BEC voltage is set to with the programming card? If it is any value higher than 6.0 volts that would be your most likely problem.

 

[JennyBudew]

Do you have the programming card to the HW 1080 ESC? The voltage that is sent to the receiver is set by the ESC. Can you check what the BEC voltage is set to with the programming card? If it is any value higher than 6.0 volts that would be your most likely problem.

I do have the programming card, the BEC was set to 7.4 and I just set it to 6.0 now. So far the twitching is still there, but not as bad as it was when set to 7.4v. The car also hasn't stopped running as of me writing this (i'm testing it out right now) i'll edit this post if it stops.

Edit: it has stopped just like before lol, took roughly 5-10 minutes after starting it up

 

[$uicide $hift]

I do have the programming card, the BEC was set to 7.4 and I just set it to 6.0 now. So far the twitching is still there, but not as bad as it was when set to 7.4v. The car also hasn't stopped running as of me writing this (i'm testing it out right now) i'll edit this post if it stops.

Edit: it has stopped just like before lol, took roughly 5-10 minutes after starting it up

I think you are dealing with two different problems. Your servos were over voltage for a period of time. Going to 6V helped but you may end up needing to replace them.

The other issue is very odd and I hate these issues. I have a go to method when experiencing odd issues like you are with the rig just stopping. I do this as a first step because it is free and I have many times caught a setting I did not realize changed. Other times just a complete reset for the electronics can resolve an odd issue. Then again it can also reappear! :lmao:

1. Put fresh batteries in your transmitter
2. Treat this as if it is a new build with all new electronics
3. Reset your ESC to Factory, reset your transmitter (if option exists)
4. Make sure all trims, sub trims are set to 0
5. Go through the steps to calibrate throttle (Fwd, N, Rev)
6. Go through all ESC options and set them to your liking (remember to set your BEC to 6.0V)
7. Set end points to your steering servo and 2 speed (dig too if setup)
8. Test drive and perform final steering trim setup

 

[Inspector86]

At this point I suspect you have damaged the servo by running it at 7.4v and it will need to be replaced. I have had great luck with the Savox 1230SG FWIW.

 

[FlatLander72]

I agree with everyone's assessment on the micro servos for the 2-speed and Dig. Replacing them should fix the glitching. The over voltage condition most likely damaged the servos.

The movement stopping after several minutes, I have two theories on. One the radio gear might be going into a fail safe condition. Does you TX/RX setup have failsafe options? Of so make sure the failsafe is set properly. You changed the TX and RX, this should rule out the radio gear, unless the failsafe was not set correctly. These are my thoughts on the radio gear.

My other idea is the ESC. Sounds like it could be going into a overheat condition. If nothing is hot, the ESC could be damaged or defective. I do not know much about the HH motors or the hobby wing controller. Make sure they are compatible. If the motor is demanding more power than the ESC can provide, it could be shutting down to prevent damage.

My $.02,


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[rob.leslie]

Sounds like you might have the battery cut off voltage set wrong on the esc. Make sure you have the lipo option set to inside the esc with the program card. Just my thoughts.

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