[Amps] SB220 tune capacitor

[Joe Subich, W4TV]

Martin,

 > I might be looking for the special end plate then, or at least some
 > pictures to see if I can fabricate one.

I had to do some review but now that I looked at some SB-220 pictures,
it seems that what they did was use a threaded stand off between the
tuning capacitor end of the 10 meter coil and the lug on the end of
the coil.  The coil remained in position but a 1.5" or so aluminum
stand off filled the space to the plate.

Here is a link to the archives of "Amps" that describes the change:
http://lists.contesting.com/archives//html/Amps/2006-06/msg00118.html

 From memory the stand-off "DA" was either 6-32 or 8-32 (which ever
matched the screw holding the 10 meter coil to the bracket with the
blocking capacitor) x 1.5."

73,

    ... Joe, W4TV


On 10/18/2010 10:43 PM, Martin Sole wrote:
> Thanks Joe,
>
> I might be looking for the special end plate then, or at least some pictures
> to see if I can fabricate one.
>
> 73
> Martin, HS00ZED
>
>
> -----Original Message-----
> From: Joe Subich, W4TV [mailto:lists at subich.com]
> Sent: 19 October 2010 09:22
> To: amps at contesting.com; hs0zed at csloxinfo.com>>  Martin Sole
> Subject: Re: [Amps] SB220 tune capacitor
>
>
>   >  Did the tune capacitor change during the life of the SB220 or>  perhaps
> with similar amplifiers? SB200 HL220 etc.
>
> Yes, later SB220 had a higher voltage breakdown (wider space, more plates)
> capacitor that was longer.  It generally came with a special end bracket for
> mounting the 10 meter coil.
>
> 73,
>
>      ... Joe, W4TV
>
> On 10/18/2010 10:07 PM, Martin Sole wrote:
>> Perhaps a question for the Heathkit history buffs.
>>
>>
>>
>> Did the tune capacitor change during the life of the SB220 or perhaps
>> with similar amplifiers? SB200 HL220 etc.
>>
>>
>>
>> I have received a replacement capacitor, well it's in UK awaiting
>> onward shipment. From a picture of the actual part sent to me it
>> appears to have two differences with the original part, these being
>> that the ceramic insulators are mounted outboard of the aluminium end
>> plates whereas on the original they are inboard and secondly that the
>> number of fixed / moving vanes is 21/22 as opposed to 18/19 on the
>> original part. I am awaiting confirmation of mounting hole spacing
>> which might be the most significant issue, assuming the min C is not now
> too high.
>>
>>
>>
>> Any thoughts?
>>
>>
>>
>>
>>
>> Thanks
>>
>> Martin, HS0ZED
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>
>