ok, after a lot of trying / filing / fitting i finally found a strongenough piece of plastic. with it, i am able to turn that pot. here's the
however: the width of the screen only changes
slightly, sometimes the word PRESS at the left side of the screen reads just SS, sometimes it's al least half an R and ESS - but not more. i can turn the pot just by mere fractions but i can also turn it in bigger dimensions - the result stays the same. i can't check perfectly what happens when i turn the knob in varying degrees, because i don't have a large enough transportable mirror here to turn and check at the same time, so it's turning at the back, checking at the front, turning at the back, ... you get the picture.
from what i can tell right now, this isn't working as it is supposed to be

. is it possible that the width coil is damaged (as i've stated above, it's wobbly)?
btw, the color problem might indeed just be a matter of color correction on the monitor's neckboard, at least that would be an easy fix!
suggestions?