I just bought a new CS8 from QC (the DIY kit). Everything is wired correctly, and all the motors rotate correctly... except motor #6. Regardless of the power I give it, it twitches at the same rate. Here's a video. I'm using the motortest in MKTool. Any ideas? Thanks Zach
Have you tried swapping this motor with another one from another boom to see if it is the motor or the attached BL?
Switched it with boom 5, same twitch. It's been almost 3 weeks putting this thing together, I was right about to fly it :/
Zach the BL is the thing that the motor wires connect to. It is what controls the pulses and power to the motors. To see if it is possibly the BL power up the copter and look at the bottom of the BL that is connected to the bad motor. You should see a couple of LED's on the bottom. There is a green and a red. After the initialization sequence all of the BL's should show a green light. Check to see if you have a solid green light on BL#6. Bit of instruction with photos can be seen HERE.
And BL means Brush Less. So BL-Controller in MK parlance is Brush Less Controller. Everyone else in the world seems to call them ESC - Electronic Speed Controller.
Can you also double check the wiring from the power distribution board to the motors. That might cause this problem (although it usually causes the motor to spin the wrong way). Andy.
I checked the lights under the PD Board -- all green. Wiring is good, no bridge, good solders, correct colors to colors. When the motor spins, it spins clockwise half a turn. Pauses. Spins counterclockwise half a turn. Repeats. Increasing the power doesn't effect the motor. I think it's just a bad motor.
So if you plug in a different boom and motor to that controller it works fine? If so then you know the problem is on the boom.. Either bad connection or motor.
Zach, since you switched the motors and got the same problem on that BL you might want to use a magnifying glass to inspect that BL paying close attention to the soldering of the motor wires. Can you send closeup photos of that BL?
Zach: If you have already swapped motors, it cannot be the motor -- it has to be something specific to the electronics that control that motor. As Gary correctly says, have a good long, close-up, look at where you soldered the motor pig-tail wires to the MOSFETs on the PDB. If you have just the smallest whisker of solder/wire bridging between two MOSFETs you can create all sorts of problems. My suspicion is that one of the three motor wires is not supplying power. You might even want to "re-flow" the solder on all three MOSFETs. Do NOT leave the iron on the solder for longer than you need to -- the idea is just to melt and re-form the solder joint not cook it like a well-done steak! Also, as Gary says, please post a close-up image of where the motor wires are attached to the PDB. Andy