Emu XL-7 & MP-7 User's Group

Greetings:

Just wanted to introduce myself to the group.

OK, so I just bought ( received in mail today ) an xl-7 off of ebay, 
but the selector knob ( the round one above the cursor keys )
is not attached ( was laying free in the box ).

OK, so how do I attach this knob again ?

Looks like there is a metal receptacle with 4 prongs on it at
the base for the know, but the know doesn't seem to click into/on the 
base.

Help!!!

Thanks,


JayB.
Austin, TX