[Hammarlund] SP-600 IF mod, is it worthwhile? OTHER notes.

[Philip Atchley]

Hi,

I'm still overhauling a JX-14.  This set had a number of mods, 'most' 
undocumented that I'm removing during the overhaul process (put it back 
original).

It DID have one mod that is documented for the JX17, that is, a front panel IF 
gain control for tube V9.  In this case it was poorly implemented, sloppily 
done, and the cable coax cable to the front panel corroded green where it had 
apparently become waterlogged sometime in the past (I'm surprised there aren't 
other noticeable signs of water damage).

The further I get into this set, the more convinced I am that is was in some 
sort of building fire (perhaps why the coax was corroded?)  INSIDE ALL the IF 
shields, bakelite parts inside the IF cans,  etc there was a even coat of 
black "soot", as well as what was apparently soot contamination in the more 
"inaccessible" locations of the set (gear train, under wire bundles, Coil 
modules, RF Subchassis etc).  No, it's not nicotine.  What is surprising is 
that the set was reportedly last used a couple of years ago and operational, 
though it needed some "TLC".  A COMPLETE teardown and rebuild (which it's 
getting) is probably more like it

ANYWAY, the question is this.  Is this "IF Gain Mod" that was designed to 
allow balancing of JX-17 receivers in a diversity setup, of any REAL use in a 
JX-14 that will obviously be used as a stand alone receiver?  It appears that 
about all it would do is reduce the overall IF gain (and AGC action?) of the 
set.

73 de Phil,  KO6BB
991 Different NDB's heard to date.
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