firstly ensure the power is off.
Then on the outer casing there is a screw top and bottom. remove these and pull the front cover off.
you can now align the knobs to where they need to be and then refit the cover.
If it helps: Before you remove the cover turn the bottom knob to minimum and the top knob to off and this will make it more straightforward to align them.
Hope this helps.
Paul
Paul, December 2009