need spezial tool to open the case?

\vendors on eBay sell a full set of the most common security bits for a few pounds/dollars.

I got a set of 32 different bits for £4.

Marc
April 2015

They don't like users taking risks poking around inside electrical appliances - so they use security screws - mostly Torx...

http://en.wikipedia.org/wiki/Screw#Types_of_screw_drives

If you don't see driver bits for these in the shops then you're in the wrong shops or you're looking in the wrong place.

Amazon sell Security Bits - very inexpensive.

A Driver
October 2014