Parkzone J3 Cub Problem
03-29-2009, 09:39 AM
#1
Parkzone J3 Cub Problem
Hi,I have a Parkzone J3 Cub that has a problem.Two weeks ago I ran down to the open field where I fly and accidently pluged the two pin conector in backwards as it is getting a little wore out.I seen a little puff of smoke and instantly unplugged it.Upon plugging it back in the correct way Everything powered up but the motor just pulses slowly and then quits.I asked one of the electric guys at the club where I fly Nitro what is wrong and he said it may have burned up the ESC so I put a new one of those in the plane with no change,motor still just pulses for a few seconds the dies.Is it the battery or did it burn up the brushless motor or the RX or what.I don't want to turn this into a money pit.[sm=72_72.gif]
03-29-2009, 11:33 AM
#3
My Feedback: (4)
Join Date: Jul 2004
Location: Lakeland,
FL
Posts: 7,906
Likes: 0
Received 0 Likes
on
0 Posts
RE: Parkzone J3 Cub Problem
It could well be you damaged the esc, motor, pack, servos and/or the receiver when you plugged in the pack backwards. You caused a dead short. So in reality any of the components in the system might have been damaged.
Hopefully it wasn't a lipo battery, as when you short them, they can get ugly real fast or sometimes even after a while after you damaged it. If it is a lipo battery, I can't tell you strongly enough to put it outside away from your home, it can catch fire all on it's own.
Just guessing from the number of posts you have that you're new to the hobby. My best recommendation would be to find somebody near to you that has experience in electric powered planes. It's going to take some parts swapping at least to find out what all you might have damaged.
Without some experienced help, you are going to have to try swapping parts on your own.
First try another battery you could have shorted out some of the connectors to the individual cells, or the cells themselves, which would reduce the voltage to the rest of the system.
Next, since you already replaced the esc, I'd try a different motor. As if the esc smoked it's a chance it fried the wiring in the motor, which would cause the motor to run slow and stutter.
Normally if you can say something is normal in an electrical system, plugging the pack in backwards for a brief second, normally shorts out the esc first, followed by the motor, and then the pack.
Hopefully it wasn't a lipo battery, as when you short them, they can get ugly real fast or sometimes even after a while after you damaged it. If it is a lipo battery, I can't tell you strongly enough to put it outside away from your home, it can catch fire all on it's own.
Just guessing from the number of posts you have that you're new to the hobby. My best recommendation would be to find somebody near to you that has experience in electric powered planes. It's going to take some parts swapping at least to find out what all you might have damaged.
Without some experienced help, you are going to have to try swapping parts on your own.
First try another battery you could have shorted out some of the connectors to the individual cells, or the cells themselves, which would reduce the voltage to the rest of the system.
Next, since you already replaced the esc, I'd try a different motor. As if the esc smoked it's a chance it fried the wiring in the motor, which would cause the motor to run slow and stutter.
Normally if you can say something is normal in an electrical system, plugging the pack in backwards for a brief second, normally shorts out the esc first, followed by the motor, and then the pack.
03-30-2009, 04:17 AM
#4
RE: Parkzone J3 Cub Problem
Thanks alot GG.I was thinking it could be any of those problems.I really don't want to go down that road right now as I have other projects in the works. It was just nice to have a small plane to load up at a split second and head out to a field.Guess I'll hang the plane up for now and maybe later see if I can track the problem down.I am new to the hobby as is my wife,and we are both learning how expensive it can get real quick.(Well,I already knew)
Thanks.
Red.
Thanks.
Red.
03-30-2009, 04:57 AM
#5
My Feedback: (4)
Join Date: Jul 2004
Location: Lakeland,
FL
Posts: 7,906
Likes: 0
Received 0 Likes
on
0 Posts
RE: Parkzone J3 Cub Problem
Is this the brushed or brushless Cub? If it's the brushed Cub, diagnosis is a little easier.
Unhook the two motor wires from the esc, also remove the prop. Take a pack of the correct voltage(don't try the suspect pack) and hook up the motor directly to the pack.
Red wire to battery positive, black wire to battery negative. Motor should run up to full speed, if it does the motor more then likely is good. If it doesn't you know you have a problem there. If you're careful, you can run up the motor this way with the prop on to verify that it feels like you're getting the proper thrust, by feel.
If it's a brushless, pull the motor and smell it. You'll be pretty quick to find out if it got hot and toasted, also look at the wiring for signs of an overheat condition.
One other thing with a brushless that will cause a problem that you can't see. If the magnets in the motor get too hot they will loose their power, which in turn means the motor will spin up fine without a prop on, but with the prop on it will have no power, thrust/speed.
Unhook the two motor wires from the esc, also remove the prop. Take a pack of the correct voltage(don't try the suspect pack) and hook up the motor directly to the pack.
Red wire to battery positive, black wire to battery negative. Motor should run up to full speed, if it does the motor more then likely is good. If it doesn't you know you have a problem there. If you're careful, you can run up the motor this way with the prop on to verify that it feels like you're getting the proper thrust, by feel.
If it's a brushless, pull the motor and smell it. You'll be pretty quick to find out if it got hot and toasted, also look at the wiring for signs of an overheat condition.
One other thing with a brushless that will cause a problem that you can't see. If the magnets in the motor get too hot they will loose their power, which in turn means the motor will spin up fine without a prop on, but with the prop on it will have no power, thrust/speed.
