Help! Rear standard of my Linhof Technikardan 45S won't tilt. How can I fix this?

[manfrominternet]

Hi all,

So the rear standard of my newly acquired Linhof Technikardan 45S won't tilt.

Here's an image of the rear standard so you can see what I'm talking about:


Usually, to tilt the rear standard forward or back, you have to pull the upper green lever down to loosen the tilt, then push the little metal lever (directly to the right of said green lever) to the left to unlock the detent.

In my case, I can pull down the green lever, but when I push the little metal lever to the left, the locking pin for the detent won't unlock, thus not allowing me to use any rear tilt.

It looks like the rear tilt detent locking pin is stuck.

Does anyone know how I can fix this?

Many thanks!