Are you sure you are using the proper cables internally?
I've occasionally had similar issues with other SBCs, peripheral cables and enclosures.
I had an Ampro SBC with PC/104 interface with an additional Ampro VGA PC/104 board in an Ampro enclosure.
At some point, I had to upgrade the Ampro VGA PC/104 board to one which supported a higher monitor resolution.
I replaced older board with another newer Ampro VGA PC/104 board plugged back in the internal VGA cable running to VGA connector on the outside of the enclosure, plugged back in the VGA monitor and powered back up the system.
Immediately the newly install Ampro VGA PC/104 board burned up.
Needless to say, the new Ampro VGA PC/104 board required the replacement of the internal VGA cable as well, even though both were Ampro.
BigDog