[Collins] 32S-1 Slug Rack Concerns

[Herzog]

For you history buffs.
There was a time when I worked at the Cedar Rapids plant, as what they 
called a "Collateral" engineer, which meant working with the factory, and 
spares departments.
I was assigned the 51J's, 75A's and N's receivers, 1958 to 62.  It was what 
they did with new engineers, to help them learn to think of manufacturing, 
in subsequent designs.

When they discovered that they were out of slugs; it turned out that the 
parts department had a policy of dumping out everything that was over a 
year old. It took a lot of hoops to jump through to get the slug 
manufacturer to dig up the old tools, and to buy a bushel-basket-full 
minimum order, and then to try and get an exception made for THE COMPANY 
policy.
Will    K 2 L B ;  ex-K0LTH
At 02:23 PM 1/3/03, Dr. Gerald N. Johnson, electrical engineer wrote:
>In my 32S1 manual, the slugs on the rack are never adjusted once they
>are physically aligned with the tops of the IF cans with the rack tuning
>set to 3.5 on the logging scale. They need only to physically track.
>Each band has its own trimmer capacitors. If the slugs aren't lined up
>with the tops of the coil forms at that setting, they are wrong. The
>ceramic material of the slugs won't have changed permeability unless its
>grumbled away or badly cracked. It is possible for some slugs to be
>shorter than others by faulty replacement or by having crumbled from
>mishandling. Even with the slugs in different positions, if the
>capacitors for each band are set by the book it would work perfectly at
>the frequency in each band where it was aligned, the only thing that odd
>core position or composition should do is make it tune less well across
>the band (and then it will track worse at WARC bands because they don't
>have their own trimmers).
>
>The slugs are probably mismatched in position because someone tried to
>peak them AFTER twiddling the trimmer capacitors to random positions. In
>the classic radio tracking days, one tuned the slugs at the low end of
>the tuning range and the (single for the whole tuning range) trimmer
>capacitor (per tuned circuit) at the high end. That technique isn't
>necessary when there are individual trimmers for every band the radio is
>designed for.
>
>Unless the book was written in error (and I didn't especially like the
>first 75S3B that came with my receiver, so I wrote the next edition)
>alignment by the Collins book should result in a superbly working radio
>(so long as there are no bad parts to upset performance).
>
>Its possible that tolerances on some band may make a trimmer capacitor
>peak at maximum or minimum C. Then the whole rack needs to be moved a
>little to all that capacitor and all the trimmer capacitors for that
>band to tune away from max or min. There should be no need to adjust a
>slug, and indeed, if one compensates for that capacitor at the limit by
>moving a slug, then ALL the bands already peaked on that tuned circuit
>are no longer aligned. So move the whole rack to get away from a trimmer
>capacitor at the limit.
>
>Now if you get a condition where moving the rack runs one trimmer to max
>and another to min on the same band, then you will have to move one slug
>or both and then start over doing all bands ignoring that initial
>setting of the slugs to match the coil tops.
>
>I type fast but this has probably taken longer to type than it should
>take to align the RF section of the transmitter.
>
>73, Jerry, K0CQ, Technical Advisor to the CRA
>--
>Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
>Reproduction by permission only.
>Sponsored by the Collins Radio Association
>http://www.collinsra.com