hi,
i must say that the recommended way is to go to your local Korg-dealer, but if there is noone near you...
ah ok the volume slider; unfortunately i can not serve you with a picture of the volume slider, because the power jack was a bit easier to access, but maybe it is not that more complicated.
do the following:
* the good news is: you can easily screw out _all_ screws from the lower side of your X50, nothing will happen if you do it, but...
* ...all screws are self cutting into plastic or iron sheet. So my tipp is: after the repair job every screw must go into its own hole back again of course, as the screws differ in length from 10-30mm.
* screw out the screws from outside to the middle and lay down the screws so that you know, or be able to remember, it's position.
* after the repair job, screw in the screws from the middle to the outside, and always try that every screw find it's way back into the hole on it's own, really without force. Especially at the open rectangle line because these screws go into iron sheet.
The bottom case part can then be opened easily. The upper case part contains all the installation, keyboard, cables and electronic main board. It only is connected to the bottom case part through some cables to the power jack plate that is screwed into the bottom case part, so another four screws have to be screwed out to separate the bottom from the upper case parts.
so your job now would be to locate the volume slider and do another few screws...
happy screwing
OlimilO
PS.: OK picture(s) next day coming soon...
http://rapidshare.com/files/215136182/IMG_2918.JPG.html
i do not know if this picture can help you.
good luck