Hello JUIT! Blissterd1 in Tulsa here waving a hand! I own a CZ5 and a CZ6A, using Sun Ray Invader inline probe and what a joy they are to use. I'm 57 and kinda busted up physically so the weight is an issue after a bit but when I'm digging coins and silver (my last outing yielded a nice James Avery men's sterling wedding band!) I can swing for 6 hours straight! I hope you got your DISC multi-switch fixed. That would suck! BTW, when you said "knob" I thought you just needed the actual knob itself, seems that you need the entire position rotary switch assembly. If you haven't found it yet, I would suggest Mouser Electronics or Digikey. It is a tiny little thing, about 1/2" around if you're looking at the part inside the unit, behind the face plate. I wonder why I cannot see the pictures you posted above. DO they still reside on the host site? I was curious since I'd like to do a hip mount with these admittedly heavy units, especially with the inline probe hanging under the s-bar.