I have this with my c300mkiii and it may have been and improper connection of SDI and power to the monitor. Like a power surge that shorted out the port on the camera. Just a theory. If you have any success let me know.
We have 2 at the shop and both models have this same issue... i have a theory...I think it's from a power surge through SDI port and connecting power to the external monitor we use which is a SmallHD
