[Premium-Rx] COLLINS 51S-1 RF ALIGNMENT QUESTION

[Mac]

Pat,  many many yrs ago i asked the same question of Charlie Talbot and 
with little doubt Charlie has done hundreds if not near a 1000 of these 
receivers, here on our side of the water, and is well thought of as the 
go to GUY,  but what i understood and why.

Drive the slug down or into the coil form as far as it will practically 
speaking go..  Then simply back it out using the 5/16" as a guide only 
tool... this positions the slug within the coil body at the mid range 
point, and later in your tuning efforts you will then come back to these 
individual or respective coils and tweak or peak them for optimum signal 
with respect to the individual band or freq range of the section you are 
working in..

I used and still use a stiff piece of cardboard or any like material  
and stand it next to the slug STEM, and then just establish a bottom or 
end point and then turn out the stem until i reach the desired range 
extracted or withdrawn desired length.  I have also used a clear piece 
of tubing and small diameter where it would stand atop the coil body yet 
allow for my tuning tool/wand to fit within the inside of the tubing and 
mark mt graduation points along the tubing..  I think you get the idea, 
or most simply whatever works for you.. The goal is to establish the 
slug where enuff of the injected signal will be passing thru the 
individual slug port to hear or read a definable signal, yet still on 
your final alignment or set-up have the slug travel ability to peak for 
max or min as you desire ...

warm regards:  hope this is a bit of a help..  mac/mc  w5mc

On 1/22/2016 3:13 PM, pat1mca--- via Premium-Rx wrote:
> Greetings to All,
>
> At the moment I have a 1969 R/E Collins 51S-1 in for repair/alignment and a 1963 manual, but there are confusing differences discovered between the two concerning the RF section alignment.
>
> There are many very knowledgeable 51S-1 owners who might know the answer to this, so here goes.....
>
> On Page 4-5  Section 4.4.6  R-F Alignment in paragraph c. it states: "Set the main tuning slugs, L32, L68 and L72 to 5/16 inch less than full insertion into the coils"
>
> OK. So does this mean 5/16 inch from the top of the slug down to the top of the chassis as a reference OR is it 5/16 inch up to the coil slug in the coil former using the open end of the coil former as a reference below the chassis ?
>
> A later version 1975 Rev 11 manual is on order from the USA but in the meantime this is intriguing me. It is obvious that a previous owner has played around with the RF side and I need to start from basics again. The last time I worked on one of these fine receivers was over 30 years ago. I still consider them to be a "Premium Receiver", the extremely clever mechanical design is unsurpassed.
>
> A definitive answer would be greatly appreciated.
>
> Thanks
>
> 73 de Pat G3YFK
>
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