Troubleshooting potential motor / ESC issue

[GuruAnt]

Hi,

I'm hoping someone can help me! I got a Top Gun Pro Heli Rapier 450 for my birthday last year, and I've had a run of bad luck. First of all, my daughter got hold of the remote and flipped all the DIP switches, which meant I had to take it back to the shop to be set up again. Then I dinged the rotors off the ground when trying to hover without training gear. It's irritating as I'm trying to be careful, I've got simulator software, and I'm following Radd's method.

After fitting replacement blades, the latest problem is that the motor just doesn't seem to be running. It was acting a little funny on the last couple of times I've had it out (not starting till the throttle was around 50%, randomly losing power), but now there's nothing at all. The servos are still working, the collective is still working, but neither the main, nor the linked tail rotor spin.

So, I'm guessing that it's a problem with the motor itself, or the ESC.

Does this sound right? Is there any way to tell which one's having the problem without me having to replace both? I've got a multimeter, but I wouldn't know what I was looking for.

The shop's not nearby, and I'd rather not keep having to go back every time I have a problem!

Thanks in advance.

[cjcj1949]

You can check the leads from the speed controller to the motor. One or more of the connectors could have come loose. You could try turning the motor by hand when it's out of the heli. You should feel a variable resistance as the magnets move relative to each other. You could check the bearings on the motor and make sure there is no play especially on the top bearing. You can measure the resistance between each of the motor wires. You should read a short circuit unless you have a very good meter. The speed controller needs to send pulses to the motor before it will run. You should hear some beeps and get some movement from the motor. You could also check the lipo voltage when charged and off load and when you try to run the motor. If the volts drop too far, the motor will not run. You should have 4.2V/cell off line(at least 4.15V) and the volts should be above 4.00 for a good lipo.

Chris