Identify and fix the oscilloscope probe

[17_29bis]

Hello,

I would really appreciate some help in identifying the oscilloscope probe that I would like to fix. There a problem with the 1:10 switch. Sometimes it creates a short (when the switch is moved from one position to another)  and then the resistance between the tip and the ground is 0.  So, I would want to know 2 things: what kind of probe is this  and how its body can be disassembled.  Here is some pictures:

[tautech]

Try unscrewing the tip after which the sleeve behind it can slide off and then maybe all remaining slid back through the handle.

[17_29bis]

Try unscrewing the tip after which the sleeve behind it can slide off and then maybe all remaining slid back through the handle.

Oh, thanks, indeed I could unscrew the tip but nothing is moving or sliding. May be the switch  itself should be removed  first? I also found a text on the probe saying "Made in Germany".

EDIT: looks like this is a TESTEC probe.