Observation Periscope Doesn't Work?

[Schnee]

Anytime I go to the obs periscope station and raise it (like I successfully raise the attack periscope - control-page up) all I get is a dark screen.

What am I missing here? Probably something simple.

[kiwi_2005]

Control -Insert

[panthercules]

And don't forget to lower the attack scope that you raised by hitting ctrl-pgup from the obs scope position :)