No power/signal to gimbal?

[djl7780]

Hello all,
Picked up a used P3 Advanced that has only 5 flights on it. I do not know it's exact history, but it looks to be in great condition, no signs of a crash, etc. I did purchase it knowing there was a "No Image signal Transmission"/gimbal disconnected issue. The Aircraft connects to the remote, as well as the DJI Go app. I can CSC and start the motors, etc.
When I turn on the AC, the gimbal does not move what so ever. I swapped the whole gimbal/camera with a known working unit and I get the same, no movement or anything. Like it's not getting power/signal. When I try to format the SD from the go app, I get "No SD Card".
The small grey cables going into the AC and Vision Positioning module from the gimbal look to be in good shape. What is the next troubleshooting step? What else could possibly be the issue?
Any help would b e greatly appreciated.

 

[djl7780]

Also in my troubleshooting, I noticed, when the gimbal is connected and the AC powers on, I get the chime but no LED's on the arms. When the AC is powered on without the gimbal connected, I get flashing red led's (Don't remember the exact pattern).

 

[alokbhargava]

It appears something gets short circuited. You will have to dig more.


Sent from my iPhone using PhantomPilots

 

[djl7780]

I dug around a bit more and here is where I am. Neither camera I have move at all when the AC is powered on. When they are plugged in I get no leds on the arms, when no camera is plugged in it blinks green/red it is all connected in the app/controller and then I get slow green blinks and I can actually CSC and start the motors.
If either gimbal is plugged in it basically seems like it doesn't start (although I get the startup sounds but nothing else, no leds, etc). It actually connects to the controller and app and I can CSC and start motors, etc as well...
I tested voltage at the wide gimbal connection on main board, first 4 are grounds, the other 4 pins read about 3.8 v per pin.. is that the correct voltage? I did order a new cable kit that will be here tomorrow, that has the two grey gimbal cables, amongst a few other cables.
What else can I check/test?