The AM Forum

THE AM BULLETIN BOARD => Technical Forum => Topic started by: KD1SH on January 31, 2024, 01:49:43 PM



Title: Now there's something you don't see every day
Post by: KD1SH on January 31, 2024, 01:49:43 PM
  Anyone remember that line, from the old Rocky and Bullwinkle show?
  Working on a project today; turn the chassis over, and hear a light "clunk" onto my workbench. Did I leave a tool inside or something? Turn it back over, and laying on my bench is one section of stator plates from a two section air variable. Really? I've never heard of that happening, much less seen it. Looking at the picture, you can see what appear to be the remnants of a very poor solder joint.
  Now to see if I can repair it. The rub—or lack of rub, hopefully—is to hold it in place while soldering. I'm thinking of strips of paper inserted between rotor and stator plates, to keep them separated.


Title: Re: Now there's something you don't see every day
Post by: KA3EKH on January 31, 2024, 02:52:36 PM
You will indeed be pulling a rabbit out of your hat if you can get that thing lined up soldered back in place, looks somewhat iffy to me.
Always liked the Rocky and Bullwinkle Show, think somehow, it’s an analogy of my life maybe I have always thought of myself as “Mr. Know-it-all” or as Rocket J Squirrel would say “And now, here to tell you everything about anything is Mr. Know-It-All.” That’s me.


Title: Re: Now there's something you don't see every day
Post by: W1RKW on January 31, 2024, 04:33:17 PM
I never had the stator fall out but on one occasion had the plates of the rotor fall off the shaft.


Title: Re: Now there's something you don't see every day
Post by: KD1SH on January 31, 2024, 07:31:03 PM
  I was able to fix the cap, but it was a tricky bit of soldering. I was amazed at how the manufacturer assembled this thing. In the picture showing the attachment of the remaining intact stator, if you look closely you'll see that all they did was to stretch out a blob of liquid solder and create a solder bridge across a roughly 3/16" gap. Quite a trick, and one that I couldn't duplicate, since they must have had some sort of fancy fixture gizmo to hold the stator rigidly in place while they they teased the solder blob into shape. The instant you touch a soldering iron to that solder bridge, of course, it melts away.
  I wound up making tiny little brass support brackets, and soldering them to both the stator assembly and its terminal. Folded paper strips wedged between rotor and stator plates held them in position during the operation.


Title: Re: Now there's something you don't see every day
Post by: KD1SH on January 31, 2024, 07:40:21 PM
  Rocky and Bullwinkle was a great show, with clever humor and witty writing that paved the way for prime-time adult animation, like the Simpsons, decades later. My wife got me the complete series on DVD for Christmas last year.

You will indeed be pulling a rabbit out of your hat if you can get that thing lined up soldered back in place, looks somewhat iffy to me.
Always liked the Rocky and Bullwinkle Show, think somehow, it’s an analogy of my life maybe I have always thought of myself as “Mr. Know-it-all” or as Rocket J Squirrel would say “And now, here to tell you everything about anything is Mr. Know-It-All.” That’s me.



Title: Re: Now there's something you don't see every day
Post by: W3SLK on February 01, 2024, 10:51:04 AM
You did an awesome job to recover that! Maybe next time go to your local auto parts jobber and get, (if you don't already have it) a feeler gauge, like what you would use for setting spark plug and points gap!(Did I just date myself?). I had an NC-2-40D where the previous owner somehow managed to move the plates on the tuning cap and had to be reset!


Title: Re: Now there's something you don't see every day
Post by: KD1SH on February 01, 2024, 12:39:47 PM
  Honestly, I might not have bothered if it were not for the fact that the chassis was already drilled, and space reserved, for that cap.
  I actually tried a feeler gauge, but although the thickness was fine, the blades were too wide to fit. A good reminder, though: I once had a nice kit of both plastic and brass shim-stock; very handy stuff. I don't know where it ran off to, my workshop being somewhat disorganized. I'll make it a point to obtain some more.


You did an awesome job to recover that! Maybe next time go to your local auto parts jobber and get, (if you don't already have it) a feeler gauge, like what you would use for setting spark plug and points gap!(Did I just date myself?). I had an NC-2-40D where the previous owner somehow managed to move the plates on the tuning cap and had to be reset!


Title: Re: Now there's something you don't see every day
Post by: Carl WA1KPD on February 01, 2024, 07:25:31 PM
Well done!


Title: Re: Now there's something you don't see every day
Post by: KD1SH on February 01, 2024, 08:59:07 PM
  Thanks, Carl. I must admit, though, in all honesty and humility, that soldering was part of my profession for most of my working career. I worked for fifteen years in an R&D lab as an Engineering Technician, soldering everything from 0201 size SMD components, (twelve thousandths wide by twenty-four thousandths long) to soldering #40 copper wires to individual legs of 80-pin quad SMD packages. Before that, I did mil-spec soldering in the aerospace world. The hands of a surgeon, maybe, but I dance like a three legged cow.

Well done!
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands