[Hallicrafters] SX-71 CW Pitch control question

[Julian Bunn]

I've just subscribed to this excellent list, and hope someone can
give me some advice.

I'm resuscitating an SX-71 that arrived in a pretty poor state
cosmetically. Electrically, from the limited tests I did, it
seems to be OK.

One problem is the CW Pitch control. This had a non-H knob, and
the control shaft was bent. In fact the front panel looked like
it had taken a whack with a sledgehammer in that region :-(

When I tried to gently straighten the shaft, it broke off ... I then
removed the whole control, and disassembled it. The shaft is basically
a screw thread with an iron core at the end, that moves in and out
of the inductor coil. 

It appears, from the shape of the cutout in the front panel for that
control, that the original knob must have had some sort of
tab that only allowed the shaft to rotate through almost 360 degrees
(there is a tab protruding in the hole). 

I have a picture of the disassembled control here:
http://pcbunn.cacr.caltech.edu/jjb/Hallicrafters/pitch_inductor.gif

(There are more pictures at
http://pcbunn.cacr.caltech.edu/jjb/Hallicrafters/ for the curious.) 

I'm wondering if I can perhaps simply break off the remaining short
copper threaded shaft, and glue a longer replacement shaft onto the
iron core piece? I imagine getting hold of a replacement knob is
going to be hard.

There are several other little problems, which I'd love to describe,
but I wont push my luck :-) (The story of the S meter is one ...)

Thanks,
Julian