I found a small screwdriver...... /ubbthreads/images/graemlins/smile.gif
Managed to turn it... first turned it clockwise; and the dot and beam became dimmer... turned anticlockwise, obviously had opposite effect....
although, even when id managed to turn it to the point where the dot/beam was brightest...... it didnt really look any brighter than it was when I had started....
Maybe its just a psychological thing (I remember the dot brighter than it was?), and I should have turned it counter-clockwise first....