I have a Durst Laborator L138s which has a slight problem, I wonder if anyone can offer some advice on fixing it.

The baseboard which is on a carrying arm (and which is able to move up and down by twisting a knob and pressing down on a foot-pedal) moves slightly from left to right when it should actually be locked in place. This can be an issue since it doesn't take much pressure in order to move it. I'm thinking that something needs tightening, but I'm not sure what.

Any advice would be much appreciated.

Thanks for your time,