great_stuff

Hi there! New to the forums.

Wonder if any experts here could help me. One of my cars is the cheap but fun GPTOYS 1:12 Scale 4WD "McGruff" S926 RC Truck. It uses an ESC/Receiver called HBX 12891 1/12 ESC Speed Controller Receiver Unit 12522RT.

I noticed how it would just stutter all of a sudden, specially if you would give full throttle, it would either not move at all, or stutter, if you give throttle bit slower you would be more successful, but all and all the car became useless pretty much useless. I tried different batteries in both Radio and car itself with no success.

Started looking into it and came up with that it must be the ESC/Receiver (combined unit). So I ordered in a new one, got it in place, and same thing.. maybe slightly better. The radio has slow and fast speed setting, and I can tell it's definatly working better when on slow setting, although not perfect.

When the stutter happens, the ESC light is blinking.

The only things I can come up with now is:

1. Radio unit itself?
2. Motor itself?
3. Solder on the motor?


This is obviously a cheap car, so i dont wanna spend too much money on it, but its been a fun car and its well built for the price, I only paid $100 cad for it.

What would you suggest I continue with and it what order? Anything else that I could be missing?

Cheers

Matt

rgburrill

You have your answer

bill_delong

Not uncommon for motors to burn up often in smaller than 1/10 scale cars, more than likely that's your problem here. I would also invest in a temp gun so you can better understand the limits of the car too:
What gearing for upgraded electronics?

Good Luck!

great_stuff

Thanks for your tip.

A motor for this little thing is only around $15-20, so I will consider getting a new one after checking solder on the current one.

ryan_t888

What battery are you using? Is it in confirmed good condition?

n my experience stuttering can be related to the battery with voltage drop outs

great_stuff

Hi

Dual batteries like these ones:

"tenergy.com/30015"

I tried replacing them, no difference.

great_stuff

Good guide you had there, temp gun ordered!

ryan_t888

If you have replaced everything and see no difference with factory stock parts, my next suggestion would be to swap components for a name brand. Doing this will begin to get quite expensive, there may become a time when you think its best to just grab a name brand RC that will be reliable for you.

great_stuff

Yeah i agree.

Since it seem like we narrowed it down to either motor or Radio, i believe replacing motor is worth it, radio is not.

jsauquet

Hi Matt, experiencing the same exact phenomenon with my kids Funtek MT4 4x4 RC Truck. It uses the exact same ESC/Receiver called HBX 12891 1/12 ESC Speed Controller Receiver Unit 12522RT.
It's been a while it wasn't used but was working fine before. Recharged all batteries (for the remote and the truck) but what ever set of batteries I use I have the same problem. Strange thing is does receive a signal as it stutter as you, but direction does not work at all.

Curious to know if you had any luck by replacing the motor or the radio?
I don't believe it's the motor, in my case replacing the motor wouldn't not resolve the direction problem.
Check all cables, batteries... everything is fine.
Thanks,
Jerome

RustyUs

To rule out the brushes are not hung up inside the brushed motor, just remove the motor and connect directly to a battery. Depending on voltage, the motor may twerk a bit, so keep a hold of it. Running brushed motors while hot, and possibly in less than ideal conditions...once the motor cools down, things can change inside the can a bit. It would be a good time to clean out the motor and relube the bushings/bearings. Brushes do wear down and there comes a time when poor contact is made with the comm.

great_stuff

Hi there

jsauquet intersting that you having same issue

Here is the latest from my troubled little car. I'm afraid I think I will have to give up. Just because it's not worth spending more money on a $150 car.

In total I've:

- Replaced ESC
- Replaced motor
- Tried 3 different set of batteries

Still same thing... very frustrating. But I think it must have to do with the Radio/Transmitter.

New little car ordered for the kids. It's not all waste though, old car and parts can still be used for parts since many of these little cars use same parts.

Thanks for comments and ideas all!