Glad to hear that you got it goin, now whatever you do don't touch that knob!
Once you pop the cover open and remove the plastic adjustment knob you'll find a pot. like these:
http://www.alibaba.com/product-gs/20...ter_piher.html
soldered to the board.
The original potentiometer has only about 270degrees (3/4 turn) of adjustment for the entire range so fine tuning it on the short end is very difficult. I replaced it with a 10-turn pot that looks like this simply because that was readily available and fit in the case:
http://www.c-stamp.com/CS527000.htm
I don't remember the exact resistance but I can did it up if anyone's interested. 10k ohm is ringing a bell though. Because it was now a little hacked you had to open the case to adjust the frequency, but once it is dialed in you should never have to adjust it again until you change tanks. I've heard quite a few ppl complain about the difficulty in tuning the wavebox, I don't understand why Tunze chose that particular style of pot.