I replaced the fan in my 5D and thought everything was fine, but after a couple of minutes, the drone would power down and the drives were very hot. Investigating, I found that on plugging in the power, the fan would come on, but then switching on the Dropbox, the fan would switch off - never to run again.
I suspect that the fan controller is broken - but does anyone know where that is? I assume it is near the drives, but can’t see anything resembling.
For the meantime, I just hotwired the fan to 12v so it is on full and continuous - so rather noisy!