[HBR] Socket for BC-453 IF transformers?

[Mike Hanz]

shoppa_hbr at trailing-edge.com wrote:

>The IF transformers in a BC-453 have 4 or 6 female pins on the bottom,
>and they mate with chassis-mount plugs that have 4 or 6 male pins.
>Is there an "obvious" way to find/fabricate new chassis mount plugs?
>

Not in my experience.  The later postwar ARC equipment male connectors 
for the equipment use #2-56 nuts on the rear of the pins so you can 
dismantle those for use in the transformers, but you still need to come 
up with a mounting scheme for the pins, or simply solder wire into the 
holes (ugh.)  The postwar 85kHz transformers are solder types, so I 
guess it isn't so much that as the sacrilege... :-)

>Off the top of my head I'm thinking about a PC board with 4 or 6 keystone
>(or maybe even Molex) pins in a matching pattern.
>

Sounds like a good approach to me.

>The BC-453 chassis-mount plugs seem to be very securely mounted to
>the chassis (somehow integrated to lips stamped in the sheet metal?
>It doesn't look like there's a lot holding them in but there must be
>a lot?) The material is semi-transparent and may even be mica? It's
>a fabrication technique that I'm obviously not familiar with and if
>anyone cares to educate me, I'll gladly listen!
>

You're exactly right - mica set in an aluminum rim, and essentially a 
'riveting' of that rim into the chassis.  It is possible to get them out 
of a junker - the easiest way is to use tin snips to cut out the section 
of chassis one is on and then snip up to the edge of the rim and then 
complete the cut by pulling the chassis bit apart while trying to avoid 
distorting the mica and rim.  Some folks just leave a square chassis 
section attached and mount it on the main chassis.

>The symmetry of the chassis sort of has me in a trance-like awe at
>the moment. The beauty has me convinced that it's some piece of
>alien technology - the 3x3 grid of plugs/sockets, the terminal strips
>with resistors in a square rotated 45 degrees at the center, the
>metal-can caps in a regular array around the edges, it's a masterpiece!
>

Even more so when you consider the basic layout was established about 
1934.  You can see the 1937 Type K predecessor at 
http://aafradio.org/NASM/Hmmmm.html

>How many command sets were made? Any history of the plants that made them?
>

Gordon White covered a good bit of that in his CQ magazine Surplus 
Corner articles during the 1960s, and like any open ended question about 
a single complex picture, it all depends on how you want the answer.  
Several companies were ultimately involved, and the variations are 
complicated.  I think the beacon receivers like the BC-453 were the most 
numerous in the long run, in part because the radio range system  was so 
long lived.

73,
Mike de KC4TOS