That's a good point.

I have got an o-ring in the knob. This made it very difficult to get off, and I was unhappy with the amount of force it required to get it off, and actually back on again.

I tried for a long time to get the bloody thing off, by gently rotating and moving from side to side (rocking) it off the shaft, but nothing.

In the end I put a screwdriver behind the knob, but against the edge of the casing (not the display), to apply some additional force, which seemed to be fine.

Paul.

Paul Haigh, Reg. 4120
(mk1) 6GB, Blue, 00254
(mk2) 12GB, Red, 00357