9.6V Brushed Motor

You may have broken a leg on the capacitor. "104" is a .01μF cap, if you want to try replacing it with a new one. They are cheap.

When you cleaned the brushes, is it possible you cleaned them too much?

I replaced the capacitor with one I salvaged off an old dvd player.

I don't think I cleaned them too much, they are not worn out, and seem to make good contact.

It may have nothing to do with the motor. You didn't mention why you decided to strip the motor. How is the battery pack going. Measure the voltage on the motor at full throttle and check it is getting a reasonable voltage. The cap is only there for EMI suppression - to stop motor "hash" getting into the RC receiver.

The battery pack is fine, just the motor, I tried connecting the battery pack via crocodile clips to the motor, and it still had the same problem, and I tried with a different battery pack. The motor gets enough voltage.

You did not mention if you cleaned the armature as well as the brushes. I have ran into this problem before the armature gits graphite build up from the brushes and causes loss of contact when they are cleaned. fyi the motor will not run with cap disconnected or broke. Suggest getting a new cap and try cleaning armature.

Sorry, which bit is the armature? I cleaned the graphite build up, as best I could, but there was lots also outside the motor.

If the motor would only spin, the pinion gear could be loose. If nothing happens after you finished, check the voltage at the motor leads. It sounds like an open circuit, either inside or outside the can. If you have voltage at the leads, then your problem is inside. Can you check for current? If you have voltage applied and nothing happens and the motor doesn't get hot real quick, you have an open circuit internal.

The capacitors are there to ground out the "noise" from the brushes which can cause interference with the RC receiver. They are not necessary, but a good idea. Without them, the performance might be jittery.

Good luck.

What I would do is go to Radio Shack and buy a new Motor rated at least 6V~12Volts,1a~2amps.

You are right, the motor WAS defective and it still is. Nothing has been changed. Its only a piece oif s**t, go an buy a new one......here I can buy 4 or 5 of those for about $1....

The capacitor is not there to make the motor run, its there to stop interference on radios and TVs, Nothing more, nothing less. The motor would run (if it were not broken) without the cap, but the neigbours might complain!!!

Does it also interfere with wireless internet?

In essence Andy is right, replace the motor if when supplied with 9V (measured while running!) it doesn't have enough power.

A likely problem is that one segment of the rotor windings is disconnected at the commutator. This will make the motor open circuit until it is rotated to a good segment. Once running it will "skip" the o/c segment and seem to run properly but with a little less power.

Regards

Chas

The capacitor is not necessary for the motor, it's "only" for EMC purposes... You should check the motor resistance with an Ohm-meter while rotating the armature slowly. If there are infinite resistance positions the commutator has worn down. Maybe you can readjust it but it seams to be easier to replace the motor.