Re: {Collins} 75S-1 Modifications



 QST Archive.

"A C.W. Filter For The Collins 75S-1 Receiver" by WA4DID

It matches his description, transistors, trimmers, xtals and

mounts in the center opening.

I believe that there is also another with a tube which mounts

similarly and adds a gain stage, but can't remember the specifics. Wait it's the

Water's Q multiplier.

Fernando N2FQ/6
n2fq@xxxxxxxxxxxxx




On Feb 11, 2012, at 2:02 PM, John Painter wrote:

> It would be interesting to have a description of what that mod is, for those
> of us who still use the 75S-1 on CW and AM.
> 
> And is that 1969 article on the Collins Website?
> 
> John Painter
> W5LQS
> 
> -----Original Message-----
> From: Fernando [mailto:n2fq@xxxxxxxxxxxxx] 
> Sent: Saturday, February 11, 2012 3:09 PM
> To: bfetters@xxxxxxx; collins@xxxxxxxxxxxxx
> Subject: Re: {Collins} 75S-1 Modifications
> 
> Hello 
> 
> QST March 1969 described what you have.
> 
> I've sent you a copy of that article.
> 
> Fernando N2FQ/6
> n2fq@xxxxxxxxxxxxx
> 
> 
> 
> 
> On Feb 11, 2012, at 11:42 AM, bfetters@xxxxxxx wrote:
> 
>> 
>> 
>> 
>> I just picked up a 75S-1 at an estate sale.  Unit is very clean and works
> great.  Got a good price on it because no one seemed to know what it was.
>> 
>> 
>> There is one modification that I have not identified.  It's mounted in the
> middle of the chassis (where the aluminum plate normally is) and contains
> two crystals (32.8 MC), a couple trimmers, a few semiconductors and several
> resistors.  I tried to attach a picture, but the Collins filters kicked back
> my email.   Will be glad to send a pix directly to anyone who might be able
> to assist me.
>> 
>> 
>> I did not yet pull the unit from the cabinet so I cannot tell you where
> this modification connects.  I did note that the unit works in the CW
> position, so I am assuming it may be related to a home brew CW filter?
> There are no holes/controls added to the front panel or elsewhere.
>> 
>> 
>> Thoughts?
>> 
>> 
>> Thanks.
>> 
>> 
>> Buck W0LC
>> 
>> 
>> 
>> 
>> 
>> 
>> _______________________________________________
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>> 
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>> 
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> 
> _______________________________________________
> SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
> http://www.collinsradio.org/membership/
> 
> NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
>  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
>  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)
> 
> The Collins Reflector reserves the right to refuse access to anyone.
> 
> LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx This ONLY goes to the
> list admins and does not post to the group!
> 
> _______________________________________________
> SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
> http://www.collinsradio.org/membership/
> 
> NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
>  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
>  1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)
> 
> The Collins Reflector reserves the right to refuse access to anyone.
> 
> LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx
> This ONLY goes to the list admins and does not post to the group!







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