[Hallicrafters] SX-111 AVC mods?

[Mike Everette]

I recently acquired a cosmetically-very-nice SX-111
Mark 1, but discovered that it has some substantial
modifications in the AVC circuit.  As yet I have not
finished tracing this out but the changes look like a
type of audio-derived AVC.  A number of solid state
diodes, resistors and a couple of capacitors are
added.

The workmanship of the changes is not good.  The
person who did them must have invented and patented
the cold solder joint.  I'm concerned that there might
be some wiring errors as well, because the radio is
dead except for some "trace" audio hum and
microphonics.  I can hear no "thump" when either the
bandswitch, selectivity or response switch positions
are changed.

Maybe the best approach to this is just to undo the
changes, but I'd like to ask if anyone knows of a
published article someplace dealing with such mods?

73

Mike WA4DLF




		
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