[Hallicrafters] S-40B alignment questions

[Bruce Wilson]

Yesterday I aligned my first tube receiver, a S-40B.

I found a couple problems:

1. My radio (from eBay) still has the paper warning covering the alignment
access holes on the bottom of the enclosure. Not wanting to disturb it, I
aligned the RF stages with the chassis out the box. Will that disturb my
alignment very much? Is it better to retain the warning in place to maintain
pristinity, or pull it off and align it properly?

2. Most of my RF stage coils were potted with wax, so I couldn't adjust
them. I guess this left my dial calibration messed up, because bands 2-4,
which all have coils in the RF stage, are not reading the correct frequency.
Only band 1, which has only variable capacitors in the RF stage, is reading
correctly. The potted coils seem to have a small rubber tube poking out of
the wax, which I think might be a way of removing a seal after the wax is
melted. My question, should I try to unpot the coils to get a better
alignment? Do all Hallicrafters come with potted RF coils?

3. I've recapped most of the capacitors (some were difficult to get at and I
left them in place) and aligned it as best I could and got a big improvement
in sound. The single biggest improvement was the 10 uF electrolytic
capacitor by the audio final amp. One capacitor I left in place was the 10
uF electrolytic by the sensitivity control, which worries me just a bit. If
that capacitor is bad, will I notice it when the sensitivity is all the way
up? Some loud stations distort rather badly until I turn the sensitivity
down (and compensate by turning the volume up). On my modern radios the
sensitivity control is used to kill images of loud stations I hear when
listening to weaker ones nearby. The sensitivity control does not effect the
sound of the loud station itself. Am I reading this correctly, or is the
poor sound of the loud station at full sensitivity a symptom of a bad 10 uF
electrolytic? To change it I need to remove the front panel, and I haven't
yet figured out how.

Thanks in advance,
--
Dr. Bruce Wilson
Department of Chemistry
Utah Valley State College
Office: Bruce.Wilson at uvsc.edu 1-801-863-7138, SB 220a
Mobile: b.e.wilson at vtext.com 1-801-360-8089