[Milsurplus] Repair of small varible capacitors

[Al Klase]

On 12/5/2024 2:17 PM, jphutch60bj wrote:
>
> Boy oh Boy A picture would be worth a 1000 words in this case.
>

*Had to grind off the bottom of the clamp to get access.*
>
> The contact spring is that the 2 or 3 pronged  metal piece around the  
> rotor blade shaft?
>
*Correct.*
>
>  1.  U-shaped spacer
>
>     A.  Spacer Material ?
>
*Hard wood, metal, or plastic.*
>
>     B.  Thickness to split the difference between the plates I would 
> assume?
>
*Yes, center the rotor plates between the stator plates.  A little 
magnification may help.*
>
> 2. Solder where in the middle and how much?
>
*A small lump to join the collar to the shaft.  You'll wan a fairly wide 
soldering tip.

As I recall it was possible to get a most of the trimmers once the 
assembly was out of the set.



This was 20+ years ago.

73,
AL
*
>
> On 12/5/2024 9:28 AM, Al Klase wrote:
>> Mike,
>>
>> I did this a long time ago, so the details are a little vague.
>>
>> The problem is that the hex adjusting collar has come loose from the 
>> capacitor shaft, and the contact spring pushes the plates together.
>>
>> I made a jig involving a small C-clamp and a U-shaped spacer so I 
>> could reposition the cap plates against the contact spring and hold 
>> things in place, and still access the hex end of the shaft.
>>
>> Then make sure the hex adjusting collar if pushed all the way down, 
>> and solder it to the shaft right in the middle.
>> (You can still adjust the cap with a 1/4" hex tool.)
>>
>> Solder them all while you're in there!
>>
>> Hope this helps,
>> AL
>>
>>
>> On 12/5/2024 9:13 AM, Mike Christie via Milsurplus wrote:
>>> Good Morning
>>> I'm in middle of restoring a BC 342 receiver. I 've done the fixed 
>>> capacitor replacements. I found I have a B+ short in the Second RF 
>>> module. After inspecting the inside of it I found several of the 
>>> varible capacitors plates were shorted. I suspect replacements would 
>>> be hard to find. I do have a BC312  hanger queen which has the same 
>>> exact module and will be installing it. My question to the group is, 
>>> I remember seeing an article on how to repair these varlible 
>>> capacitors but I don't recall where I saw it. Does anybody here know 
>>> how to fix these?  I think the fix was to drill a whole in the shaft 
>>> and put a pin in to keep the center plates from shorting to the fix 
>>> plates.
>>> Thanks for your help
>>> Mike
>>>
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>>>
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>>
>> -- 
>> ARK Sig Block Al Klase - N3FRQ
>> Jersey City, NJ
>> http://www.skywaves.ar88.net/
>>
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>>
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>
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>
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-- 
ARK Sig Block Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/
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