Well, I'm going to write the same question in different ways. On one issue.
1. You wrote: «I did this with a variable voltage switching regulator, it'll take any DC input from 11v to 40v and output 9v which I use to power the LCD, the LCD board then powers everything else.»
How it works? The converter is connected to the input in parallel with the card driver (M.NT68676.2A) ?
Input goes in parallel to the driver (M.NT68676.2A) and converter? What I see in the photo: the red wire (input, "+") is soldered to the "+" (12-35V). Next - the output (red "+" Black "-"). Where they are soldered (output)? In the photo it is not visible. For example, input 20V runs parallel to the board (M.NT68676.2A) and to the converter?
Ok, I have disconnected the middle pin of the power connector on the M.NT68676.2A, so that I can take it instead to my voltage converter, so the centre pin of the power plug of the M.NT68676.2A goes to the voltage converter, using the red wire, which converts the input voltage 12-35V in to 9v, which I then take back to the place where the power socket middle pin used to connect to the M.NT68676.2A, that is the other red wire going under the board. The Black wire goes to a common ground, the negative of the power socket, again under the board.
If you can run the M.NT68676.2A on 9V-12V then you don't need to do any of this and you won't need the voltage converter.
I think I said in the original that the M.NT68676.2A will work with down to 7V but no lower, so I chose 9V.
Hope this helps.