[ssjr0498]

Hi friends,

I had recently purchased a "Huan Qi" make AWD remote controlled truck for my nephew in the US from Sapphire toys in Bangalore.

I know that some of you would be thinking that what a fool I was to have picked up a Remote Controlled Toy from India and then taken it to the US, when I could have got a lot better quality stuff from there itself and for half the price I paid here! The thing is, it was his birthday and I did not want to greet him empty handed! I was assured by the guys at Sapphire that this is a very good brand and that they have sold multiple units and not received any complaints!

Anyway, to cut the story short, the truck ran perfectly for the initial 5 days of use! My nephew was elated! Seeing the smile on his face I was also very happy and was thinking that it was money well spent!

However, the happiness was short lived! The next day, i.e. the 6th day morning when my nephew powered it on, the truck didn't move. The wheels were moving left and right, but the truck would not move.

He got really scared and started crying! Upon asking what had happened to it as it was working absolutely fine in the night before, the only different thing that he did from the previous 5 days was to leave the truck on charge the whole night! I am not sure if this, overcharged the batteries and fried the drive motor or what really happened.

This truck has 2 motors, 1 that turns the wheels and the other that drives them. Its the one that drives them which is not working! ( For reference, I am attaching 2 pictures. Its the motor in the blue box in the 1st picture that drives the wheels and is not working)

The truck is now with me in Bangalore and I need help to find someone who could replace that motor or fix it. Since it was a gift from my end to my nephew, he is very attached to it and keeps asking me constantly as to " was I able to fix it"?

My parents leave for the US this month end! Any help will be very much appreciated!

Thanks for all the help in advance!

PS: Sapphire has washed its hands clean, they won't help!

[Arch-Angel]

I have a suggestion if you are willing to try it. I assume the truck runs on 4AA batteries. See if you can get hold of a multimeter and connect the leads across the motor terminals and power it on. On the remote, try to to press the up(whichever the throttle is) and check if you get any sort of voltage across the leads when you do it. If you do, check if you can get your hands on any motor rated at the voltage nearest to the voltage readout on the multimeter(best would be if you can check if the motor has any stickering). Then mounting the new motor should take a bit of jugaad.

[ssjr0498]

Originally Posted by Arch-Angel

I have a suggestion if you are willing to try it. I assume the truck runs on 4AA batteries. See if you can get hold of a multimeter and connect the leads across the motor terminals and power it on. On the remote, try to to press the up(whichever the throttle is) and check if you get any sort of voltage across the leads when you do it. If you do, check if you can get your hands on any motor rated at the voltage nearest to the voltage readout on the multimeter(best would be if you can check if the motor has any stickering). Then mounting the new motor should take a bit of jugaad.

Thank you for your prompt response. The truck does not run on 4AA batteries (picture attached). Also, I tried checking the box and the manual for the rating of that motor, unfortunately its not mentioned.

Is there another way to check the capacity of the motor.

[Arch-Angel]

Well, a rough estimation is possible. Reminds me of my days in the electrical machines laboratory. You might need a tacho for that to find the max rpm but since the motor isnt running we have quite a task. So officially we are stuck. Just check the maximum voltage you are obtaining across the terminals. Next you will need to look for a motor nearest to the rated voltage. You can measure the battery voltage but to measure the current you'll need a load. After which you can go about searching a motor(about 5000 rpm-10000rpm) high torque hobby motors are available in many hobby stores.

Edit: Try taking this motor along to the shop and search for matching motors (with respect to size, i dont think you might get many motors similar in size). I bought motors for the projects i did by mentioning the voltage. That was enough for the purchase.

[ssjr0498]

Originally Posted by Arch-Angel

Well, a rough estimation is possible. Reminds me of my days in the electrical machines laboratory. You might need a tacho for that to find the max rpm but since the motor isnt running we have quite a task. So officially we are stuck. Just check the maximum voltage you are obtaining across the terminals. Next you will need to look for a motor nearest to the rated voltage. You can measure the battery voltage but to measure the current you'll need a load. After which you can go about searching a motor(about 5000 rpm-10000rpm) high torque hobby motors are available in many hobby stores.

Edit: Try taking this motor along to the shop and search for matching motors (with respect to size, i dont think you might get many motors similar in size). I bought motors for the projects i did by mentioning the voltage. That was enough for the purchase.

Thanks again! Are you aware of any such shops/places in Bangalore where I can get this tested and also buy a motor if needed?

[Arch-Angel]

Unfortunately, I have no idea about bangalore(never been there ). I guess you can try asking some of the chaps over at the rc thread they had made a while back(i assume it is still up). Problem with these small motors is you do not have the wattage written on them. So even with a motor rated at 5v( lets assume two 5v motors of different power ratings .7W and 1.2W). If the battery provides 5V at 300 mA current, you would be having a power rating of 1500 mW aka 1.5W. So if the motor with the lower power rating is run at rated speed with load, itll conk out faster since there is more current so itll try to run over its rated speed thereby busting its windings(armature). This is exactly why it was made mandatory to have ratings on motors but with small toys, that analogy doesnt hold good.

[Jeroen]

Hold on , lets take it back one step. Before you start looking for a new motor you really need to try and see if its broken in the first place.

The easiest is as suggested, get a voltmeter and measure the voltage on the motor terminals. Manipulate the transmitter forward/reverse and see if you get a voltage. If not, its not the motor, but something else.

If you don't have a voltmeter, get yourself another battery that you know is well charges and just connect it directly to the motor. Doesnt mattter if the voltage is a little higher or lower, you just need an indication that the motor is working when a voltage is applied.

Did you check if you can turn the wheels by hand, thus also the motor, to put it differently, make sure nothing (mechanically) is blocking or preventing the wheels/motor from spinning?

Here are a few things you can do as well.

With an electrical problem always follow the same procedure:
Check battery voltage/capacity (appear to be fine as the steering works)

Next:

Inspect every wire and connector. Just tug gently on all wires where they are attached to something, see if they are properly attached. Take every connector apart, check that the wire is properly attached to the connector and push the connectors back together again and make sure they connect well.

Have a close look at each and every wire. Can you see any evidence of a wire being broken internally. Usuall telltale can be heavy indentation on the insulation, unusual sharp bends etc.

I would also open up the transmitter. Usually held together with a few simple screws. Take it apart and again make sure all the wires are properly attached, so visible cracks on the PCB, all components firmly soldered down etc.

So always do an as thorough visual inspection of all the obvious. Next, and for this you do need to have a multimeter, would be to check each wire for continuity and find the faulty component.

If you have voltage on the motor terminals and the motor doesnt spin, take the motor of and have a good look at it. See if you can identify the brushes, maybe something has come loose, same for the wires. I can't see how they lead into the motor, but again the might have come loose as well.

Good luck!!

Jeroen

[ssjr0498]

Thanks Jeroen,

So I looked at all the connectors and they seem to be fine. Next up is that the remote requires 12 AA sized batteries. Will update you on this one, once I get the batteries and test the voltage on the terminals connecting to the motor.

[Arch-Angel]

Jeroen sir, i had mentioned him testing the motor terminals and only go ahead with getting a motor if he was sure there was voltage across the voltage terminals.

On the remote, try to to press the up(whichever the throttle is) and check if you get any sort of voltage across the leads when you do it. If you do, check if you can get your hands on any motor rated at the voltage nearest to the voltage readout on the multimeter(best would be if you can check if the motor has any stickering).

But thats great advice in general!

@SSJ

Try using the continuity mode on your multimeter and check each leads(wires). I am sure you can fix this yourself if it isnt related to the RX(receiver) section of the RC car.

[BBR_SHR]

Maybe product description on this Amazon listing might help identify/source components if required:

http://www.amazon.com/MaxSale-Huanqi...ywords=Huan+QI

[ssjr0498]

Originally Posted by BBR_SHR

Maybe product description on this Amazon listing might help identify/source components if required:

http://www.amazon.com/MaxSale-Huanqi...ywords=Huan+QI

Thank you for the link! Yes, it is indeed this one! I have the blue colored body of it!

[Rehaan]

1000% agree with the troubleshooting method Jeroen has outlined.

First determine if the motor is getting power or not. This will indicate what the real problem is.

If its the motor that's blown, see if someone can open and fix it in bangalore (re-wind it?) - though that'll be tricky.

Here's what seems to be a replacement motor : http://www.heli-parts.com/motor-spar...es-p-6272.html

cya
R