[Collins] What Is It?

[Dr. Gerald N. Johnson]

On Thu, 2007-05-31 at 17:11 -0400, Garey Barrell wrote:
> I have what I believe to be a Collins part that I have had for literally
> years.  This is the third state I've moved it to, over 30 years.!  It's
> brand new and unused.
> 
> It's a deep drawn aluminum can, with a small variable cap, two section
> pi-wound, slug-tuned coil, three caps and a resistor.  I'm guessing it's
> a BFO can, but ...
> 
> It has three Collins style part numbers.
> 
> 278 0541 00   This number has a line drawn through it.

This would be a component specification for an RF or IF transformer
which could include a BFO coil. The two digit suffix indicates a date
sometime before the early 1960s from a time period when that last digit
only showed the paper size of the specification or drawing. So it was
neglected in parts lists and part identification.
> 
> X 328 2 CCC
> 
> 525 2122 002  The first two digits are unclear and may be incorrect.

The 52x family were assembly drawings, the 002 may have indicated B size
paper, or been an extension to the basic part number which may have
applied to multiple parts with common and differing characteristics,
like an RF coil for a receiver that was band switched with a common
circuit, a common case, a common application but different coils and
capacitors. Or in the case of a component specification, a type of
resistor with the dash numbers for the different available values.

> 
> 7-70  Date code.
> 
> So.  I'd like to know what it is, and if it's worth keeping.  I suspect
> it's one of those things no-one needs until they need it, but then they
> need it BAD!
> 

What size is the can? That might give a better hint of vintage than the
part numbers. A 1.5 x 2.5 can might be a 51J or 75Ax part. Or it might
have been made for a special project that is long forgotten and its only
value today is for the parts it contains. A grid dip meter or a Q meter
or a network analyzer could determine the resonant frequency of the
assembly and that would be a further hint. Though a two section pi wound
coil sounds a lot like a 455 or 500 KHz or lower frequency part.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer