Thanks Scott, I really appreciate the reply!
I find it extremely strange the knobs are soldered on also. You're probably right, although these knobs sure look identical to the ones in all the old Decibel Products catalogs, etc. But these knobs have NO holes for set screws or anything of the sort. At the repeater site I thought they were glued on. It was only after getting it home and in better light I realized they have a hefty brass insert and it's soldered to the rod. Strange, indeed. Thanks for the info about the grommet. Are there some with very thin walls? The hole the rod passes through appears to be only a few thousandths of an inch larger than the rod. I'd guesstimate maybe .020" clearance. I will see if I can unsolder a knob without incinerating it. I would like to keep the rods full length if I can, but there is enough length to tune my frequency even if I hacksaw through the rod below the knob/solder... drastic, but it has become pretty much unusable the way it is. 73, Paul Scott Zimmerman wrote: > Paul, > > I have seen similar construction in cans. All of the ones I have seen have a > small plastic grommet insert in the hole in the top of the plunger. It's a > plastic insert like would be in a hole where wire passes through it. They > are available at Lowe's and other hardware stores. > > I also find it EXTREMELY strange that the tuning knob is SOLDERED to the > tuning rod. I guarantee this is NOT factory. There should be 2 set screws on > the knob. Once they are loosened, the knob should spin right off. If I were > to make a guess, someone has been playing around with this can(s). > > As I see it, you have 2 options: Fix it right - Unsolder the knob, take the > plunger out, clean up the threads, re-insert the grommet and reassemble > using a new knob if necessary. > > The other option is to unsolder the plunger using a torch, replace the > grommet in the top, clean the solder from the hole in the plunger and the > rod, and solder the plunger back on the rod. Alignment is not critical since > you can simply change the tuning to compensate for any misalignment. I had > done a similar procedure to a set of Wacom cans that the silver plating on > the plunger had gotten wore off. (how I don't know) I unsoldered the > plunger, cut about 1/4" off the rod and soldered it back fast. While I had > the cans apart, I used some silver plating compound used for plating circuit > boards on the plunger to re-plate them. I used LOTS of no-ox on them when I > reassembled to try to keep them from being damaged again. After I was done, > the cans tuned great and are working fine. The only thing noticeable is that > the tuning rods are a bit further into the can when compared side-by-side > with an un-modified set. > > Good luck, > Scott > > Scott Zimmerman > Amateur Radio Call N3XCC > 612 Barnett Rd > Boswell, PA 15531
