[Hallicrafters] S40 Help again please!

[Mike Everette]

Regarding the S-40 alignment:

This advice comes from someone (me) who has aligned
numerous communications receivers.

Is your capacitor turning smoothly?  Good.  Are the
rotor and stator shorted?  No?  Good.

The thrust bearing on the variable cap is not likely
to be your problem.  DO NOT TOUCH IT.

Do not go there.

It is not impossible, but VERY VERY unlikely for it to
be out of adjustment.

Do not go there.

If you misadjust this, you are running the very real
risk of shorting out the variable by pressing the
stator and rotor together.  This will likely ruin it.

Or, at the very least, you may risk having all the
ball bearings fall out of the capacitor.  (enough to
make a man of the cloth cuss a blue streak)

This is something only a rank idiot would have messed
with in the past.  

Yes, there are rank idiots out there messing with
radios, but only a tiny fraction of them would get
into this territory.

As for the "leaf" plates, I wouldn't go there either.
This is a factory adjustment.

What I think you have, is a case of severely
misadjusted slug and/or trimmer.

I would run the slug all the way out and open up the
trimmer to minimum capacitance, then proceed with the
complete alignment procedure.  This will take a while.
 

I think you'll read in the manual about adjusting the
slug at the low end, trimmer at the high, and then
repeating the adjustments -- maybe a number of times
-- until the tracking is good.

If you have a frequency counter this would be easy. 
Just align the oscillator to the dial frequency plus
455 KHz at the low and high ends, repeating the
adjustments as necessary.

If you don't have a counter, a good old BC-221 or LM
freq meter will do every bit as well.  Just listen to
the oscillator and set the adjustments.

If you don't have one of those, can you find a good,
well calibrated general coverage receiver?  You can
listen to the oscillator with that.

The S-40 does NOT boast "frequency meter accuracy" in
tuning, but you should be able to get it within 5 to
10 per cent.

Don't forget the obvious:

MAKE SURE the bandspread capacitor is FULLY OPEN
before you try to align ANY of the bands.

Again: Forget about mechanical adjustments of the
tuning cap.  If you go there, you will be STOMPING
through a minefield, where angels fear to tiptoe.

These should, by and large, be considered factory
adjustments that are not and never were meant to be
messed with  "in the field" or at least without a
bunch of test gear you probably do not have.

DON'T destroy your tuning cap.

I haven't got my S-40 manual handy right now, but I
would be willing to bet, if this is a one band issue,
that there is a fixed cap somewhere in the oscillator
circuit that COULD be (not necessarily is) your
problem.  But I'd bet on severe misalignment first.

Alignment takes one other piece of test gear not
mentioned in the manual:

PATIENCE.  

If you don't have any of that, don't go there before
you acquire it.

And yes, I am familiar with the S-40; I'm not talking
out of my hat.

73

Mike WA4DLF





		
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