I don't know if this will help but I have a Compaq Qvision 210 monitor tht has two inputs. One is a normal VGA -> VGA input and the other is a VGA -> BNC type connector.
I can switch between them by pressing a button on the fron to the monitor. One is connected to my A1 the other to my PC
I found that the brightness was much too high on the BNC side when the VGA side needed the controls set to full brightness.
I ended up going into the advanced colour options for my graphics card on the PC and selected a lower brightness setting for (cough)Windows(Cough).
You could try and change the colour/brightnes settings in windows and see if that can work as a temporary fix.
