durst laborator CLS1000 horzontally locked

Hello fellow wet printers.
I need some advise with my Durst Enlarger Laborator CLS1000. At the lower left side of the head you have a knob which enables you to turn it horizontally. I did turn but it also is now locked in that position. I thought if I turn the know to the L position again it should release the head to turn it back to vertical position. That appears not to be the case.
My question: Is there possibly a release knob which I need to press first?

I am thankful for any hint.

Cheers
Klaus

In my experience the knob has a worm-gear mechanism, that does not allow the rotation of the head to be transmitted backward to the knob, so the head won't swing down out of control as you are tipping it over. But to bring the head back upright, I actually have to lift the head and twist the knob at the same time, the knob won't generate enough torque to lift the head on it's own.

Thank you ic-racer. I will try that.

Some feedback on the topic:
The head is up again.
ic-racer was right. Let me just add some infos for those who might come into the same situation:
You have to lift the had and keep turning the knob till the head is loose to swing in any direction. Once you have it in the wanted position you need to turn the knob again to make it lock in the position.

Spock say's 'Logical'