[Hallicrafters] More S-40A Material

[JM/CO]

Replacement of all of the paper capacitors in these sets is considered
standard restoration procedure. Some will argue that if the old ones work,
don;t replace them. Such folks are fools. Your audio problems will most
likely vanish after you complete this procedure. Test ALL resistors. Carbon
resistors have a tendency to drift upward in value with time. Also, leaky
capacitors can cause excessive current to be pulled through resistors, and
this will also cause an increase in value. I have done restoration jobs to
sets that are this old, and had to replace 80% of their resistors along with
everything else.
Chuck N1LNH
-----Original Message-----
From: J.G. Hoffman <drjgh at earthlink.net>
To: hallicrafters at mailman.qth.net <hallicrafters at mailman.qth.net>
Date: Sunday, February 03, 2002 4:30 PM
Subject: [Hallicrafters] More S-40A Material


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>I have an S-40A (Serial # HA-968798) that has an 80 (four pin base) and the
chassis is stamped "80".
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>I also have an original S-40A Service Bulletin that specifies an 80
rectifier, and a copy of an S-40A Service Bulletin that specifies a 5Y3!
Seems that not all S-40As are the same.  Unfortunately, there are no dates
or revision #s on the Service Bulletins.  They do have different fonts and
layouts too.
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>Several questions about the S-40A, which I want to restore as practice
before starting on the more complicated, heavier Boat Anchors:
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>1) I need just a little "touch up paint" (flat dark gray) to fill in the
scrapes on the case, recommendations?
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>2) The installed speaker has a lot of distortion, I plan to install a jack
in the grill at the back (no drilling) to use another speaker, this can be
undone with only resoldering the wires and taking the jack out.  Or are
replacement speakers available?
>3) There seems to be some residual distortion in the audio (even with a
better speaker), though it is listenable.  Coupling capacitor?  I was going
to test all voltages/resistors, and replace the capacitors in the audio
stages.
>4) If the system is working should I replace the capacitors anyway?
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>5) Is there an easier, or more straight forward, way to get the dial back
in calibration than endlessly tweaking trimmers back and forth and back and
forth until it is not quite close enough?
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>Joe
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>--- J.G. Hoffman
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>--- drjgh at earthlink.net
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