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Old Apr 03, 2015, 08:11 AM
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mCPx - Response goes nuts?

Hi everyone. Newbie to rcgroups.
I have been flying for a while in terms of time but not too many flights. Not enough time. haha
I started out with an aerobird. hahaha... I still fly it. LOLOLOLOL.
I have worked my way into helis. So much more challenging and fun.
I originally posted this in the wrong thread so I started a new one.

I have a blade mCPx that is frustrating me. It binds easily and I have full servo control. I have tested it for a few minutes (tried extended test time after problems below) without throttle input and there are no issues. When I throttle up, things go stupid. I lose servo control when the main motor is spinning. The left servo goes full neg and then comes back. Then the servos have incorrect response if any. Sometimes I have clean throttle control and sometimes it is intermittent. If I turn off the throttle after a few seconds, I sometimes regain proper servo control. After the main motor is spinning for 20-30 seconds, all control is lost as though the bind is dropped. No problem rebinding. It would be good if I could post a video.
I doubt it is the servos as they work fine before throttle is applied. I have tried a second main board (was brand new in package) and I get the same results. No radio (DX6i) issues as I fly other helis without problems. Even tried setting up another heli on the radio. I have not yet tried a main motor but I don't want to spend the money yet. Maybe it is the main motor causing too high a current though??
Any thoughts?
Does anyone want a non working main board for parts? Nothing is burned that I can see. I got it with a used heli purchase. Antenna and power wires are cut for some reason. I would send it for the cost of shipping only. US$4 to USA or Canada.
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Old Apr 03, 2015, 10:40 AM
HeliFlyer14 is online now
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hummm, that sounds funny for sure. It seems like you could be getting noise into the system. I normally would have suspected the control board, but you swapped that out with hopefully a new one (??). The control board on the mcpx v2 is really sensitive to power surges. If my batteries are old, I've noticed that when spooling up, the motor will kick on and off a little until it has come up to speed. If the bat is really old, then it will flat out stop spinning for a good second then kick back in and try to spool up again. This occurs after the tail motor has come up in speed and the main motor is just starting up.

I just swapped out my main motor for what I thought was a new one, and it would just drop power from the whole system after about 20 seconds into the flight. Put my original motor back, and wa-la heli flies fine again, albeit a little lower power due to the motor having some wear on it.

I have had issues in the past with the antenna wire being too close to the main motor. Once it had actually wrapped up against the main motor due to magnetic effects pulling the wire over. I now purposely bend the antenna wire to the front of the board to keep it as far from the motor as possible.

Are you routing the battery power leads away from the main motor? Could be causing some noise spikes into the wiring if right next to it.
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Old Apr 06, 2015, 09:46 AM
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Thanks for the advice. I tried out a motor from my functioning mcpx and it seemed to work. Too bad I replaced what was probably a perfectly good main board. Anyway, I wonder if the motor itself is causing problems because of too high a current (seems a likely culprit from what you said about power surges)? Maybe the capacitors are bad? I will try new caps. I also have a new motor on order. This is a weird one.

Quote:
Originally Posted by HeliFlyer14 View Post
hummm, that sounds funny for sure. It seems like you could be getting noise into the system. I normally would have suspected the control board, but you swapped that out with hopefully a new one (??). The control board on the mcpx v2 is really sensitive to power surges. If my batteries are old, I've noticed that when spooling up, the motor will kick on and off a little until it has come up to speed. If the bat is really old, then it will flat out stop spinning for a good second then kick back in and try to spool up again. This occurs after the tail motor has come up in speed and the main motor is just starting up.

I just swapped out my main motor for what I thought was a new one, and it would just drop power from the whole system after about 20 seconds into the flight. Put my original motor back, and wa-la heli flies fine again, albeit a little lower power due to the motor having some wear on it.

I have had issues in the past with the antenna wire being too close to the main motor. Once it had actually wrapped up against the main motor due to magnetic effects pulling the wire over. I now purposely bend the antenna wire to the front of the board to keep it as far from the motor as possible.

Are you routing the battery power leads away from the main motor? Could be causing some noise spikes into the wiring if right next to it.
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Old Apr 23, 2015, 09:04 PM
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I put in a new motor and it works fine now.

Weird. I thought it was the mainboard for sure. Maybe the old motor was drawing too much current or the caps were bad and causing interference.
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