Why is the flex ribbon cable burning up after installing?

[Qual]

I recently got a P3 pro which had an IMU error and limp gimbal (video works)
I fixed the IMU error and updated the firmware
The roll arm had been JB welded at some point, I bought the repair kit (not OEM), and installed it...on start up, smoke came from the SD card slot. (oh crap)
The ribbon was burnt (1st ribbon)
I figured I installed the ribbon cable incorrectly or something else, so I bought another cable (OEM), installed that and the same thing. Poof (2nd ribbon)
Im starting to think its a bad gimbal motor.
How do you test, to see if the gimbal motors are bad? the boards seem fine..im getting the correct Ohms on the POT...1/2 turn 2ohm/5ohms
is it hard to replace the pitch/yaw motors?
Id like to buy new motors, I just dont want to waste the time/money if they arent the cause of the problem
Thanks

 

[vincent228]

I found my pitch motor going bad, and it was really heating up.
It didnt smoke the cable, but was enough to heat it up enough to melt through the insulation.

Just a thought.

 

[Qual]

Thx for reply