Bad yaw motor or Roll/Yaw ESC Circuit Board?

[fa2ality]

Hi,

I turned on my Phantom and during the gimbal calibration it got stuck on something underneath it. I didn't notice until I picked it up and smelled burning, turned it off and let it cool down.

Long story short, after noticing I have very weak and uncentered yaw power, I got the yaw motor out. I saw that the last lane on the ribbon cable of the motor was burnt
so I soldered a bridge with two hairs of wire about the same size as the damaged bridge, put everything back together, and tested it. As soon as I turned it on I smelled the same burning smell, but did a quick test anyway.
It had some faint yaw power, but when it tried to center itself, the yaw is too weak and it gets stuck to the slight right or slight left. I still have perfect roll resistance.
I also tested it with my goggles with head tracking and it doesn't control the yaw at all, only the roll. I took it apart again, the ribbon burned from the exact same spot, the solder had come off and the electrical tape I used melted.

Does this sound like the solder couldn't handle the temperature, the motor is bad and it's damaging the ribbon, or is the motherboard damaged and frying the ribbon? I don't want to order a motor and the motherboard fries it, so I want to be sure which part I need to order. The motherboard visually looks perfect.

Thanks!

 

[delfin2003]

Well, the reason why it melted was because there was too much current going through the ribbon cable, which in turn overheated the thin wires in the ribbon cable and it melted. Don't turn it on again! You may risk more damage!! Somehow I doubt it could have damaged your yaw motor, most likely you need to replace the yaw/pitch/control board and the ribbon cable. That said, if you do replace it, turn it on, and you get the same behavior, then I would turn the drone off immediately. I would then assume it have somehow damaged the motor winding, at which point you have to do the yaw motor replacement procedure. My thoughts.

 

[fa2ality]

Well, the reason why it melted was because there was too much current going through the ribbon cable, which in turn overheated the thin wires in the ribbon cable and it melted. Don't turn it on again! You may risk more damage!! Somehow I doubt it could have damaged your yaw motor, most likely you need to replace the yaw/pitch/control board and the ribbon cable. That said, if you do replace it, turn it on, and you get the same behavior, then I would turn the drone off immediately. I would then assume it have somehow damaged the motor winding, at which point you have to do the yaw motor replacement procedure. My thoughts.

The damaged ribbon is the yaw motor ribbon. I'm thinking that when my gimbal was stuck on the table while calibrating it overheated (the whole gimbal was very, very hot) and melted its ribbon.
the second melt after my ribbon bridging job might be from a weak solder point, it may have bottlenecked and came undone.
I think I'll start with the visually damaged part which is the yaw motor, if I burn it then I guess its an esc board and another motor.
I'll keep you updated.