[Hallicrafters] SX-100 Mark 1A

[mvjohn at sympatico.ca]

   Hello Roy;

   I  just  finished  bringing an SX-100 Mark 1A back to life. I replaced
   the  2 line AC cord with a 3 wire cord and installed a fuse. There was
   room  under  the  chassis  for a small fuse holder. I replaced 3 leaky
   caps.  I  do  not  replace  caps  on spec as a rule. I checked all the
   voltages   and   checked   the  tubes.  The  radio  had  all  original
   hallicrafters  tubes  in  it  and  3 of them had shorts when tested. I
   replaced  the  3  shorted tube, and found I had to replace the RF gain
   pot.  Once  I  did  all  that,  I  did a complete alignment as per the
   manual.  The  alignment  proceedure  is  easy  to  follow and I had no
   trouble.  The  radio  aligned  very  well and preforms great. The only
   thing  that "bit" me......I found out the hard way that the S-meter is
   in  the  plate circuit of one of the IF amps. I got zapped a couple of
   times  as I had to remove the paper shield around the meter connection
   points.  I  now  understand  why  Hallicrafters made such an elaborate
   shield for the meter.

   The  only  other  challenge was the alignment of the notch filter. The
   proceedure  in  the  manual  is a bit tough to follow; at least for me
   anyways.  I finally put my scope on the detector output, and swept the
   50 kc IF. I then adjusted for a symetrical notch.

   I  was  reliving  my youth last night....I was using my newly refurbed
   SX-100  and listening to W1AW code practice...Just like I did 35 years
   ago....It was great!

   Mark V Johnson VE3DJU/VE3DDI
       ______________________________________________________________

     From:  roy.morgan at nist.gov
     To:  hallicrafters at mailman.qth.net
     Subject:  [Hallicrafters] SX-100 Mark 1A
     Date:  Mon, 26 Nov 2007 21:52:26 -0500
     >Halli Folks,
     >
     >A  friend  has gotten from his uncle an SX-100 Mark 1A.  I've seen
     them discussed
     >on the list with high praise.
     >
     >Most  likely  I'll  get to replace caps and do an alignment on the
     thing.  I will
     >want  to  do a good job since this is both nostalgic for my friend
     (he lusted
     >over  them  in  catalogs)  and  from  a  family member who was the
     original owner.
     >
     >I  can  see  from the BAMA manual that this is a fine receiver, in
     some ways like
     >the  SX-101A.  I  also  see  that  it  has a 50KC IF module that's
     bolted to the
     >chassis  with  some  10-12  leads  to manage.  (I just finished an
     SX-88 and had to
     >remove/replace the IF module.)
     >
     >Any tips or gotcha's on this receiver?
     >
     >Roy,
     >K1LKY
     >
     >Roy Morgan
     >13033 Downey Mill Road
     >Lovettsville VA 20180
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