White filter sounds like the Contrast setting is adjusted too high.
Have you tried a different video cable, vga or DVI (you didn't specify what type of connection)?
Have you tried using a different monitor, just to prove that the problem is in the monitor and not the laptop?
If you've tried another video cable or even a different input type and it still fails, but it is OK when using a different monitor, it may be simpler to replace the mainboard in the monitor than trying to fix it.
Search online for Acer S200HL mainboard or 3520-0052-0150 to find suppliers that suit you best.
Here's the ifixit Acer S200HL LCD Monitor Motherboard Replacement guide that may help.
If you're interested here's a link that although your monitor doesn't have the same symptoms, shows some components e.g. capacitors (check for domed or leaking), that may affect the operation. Worth looking at first perhaps.