I am resoring a pair of Hallicrafters S-40B recieivers. I started fiddling
with these radios about ten months ago. Initially, I just recapped one and
cleaned it up to give my father as a Christmas gift. I worked OK, but was
seriously in need of reallignment. The second S-40B I was planning on
rebuilding for myself.

When I tried to reallign my father's radio, I found that it would not
reallign on several bands. This problem, in addition to the poor condition
of my own, led me to decide on a complete rebuild of both radios from the
ground up (all new caps, resistors, and transformers). I worked off of
schematics for the S-40B that I downloaded off of the BAMA web archive.

Recently, I got both chassis ready to try out. They both worked ok, but I
noticed a new problem on both radios that I didn't see on the first
restoration (new caps only). When I turn the RF gain pot up beyond
approximately 66% of full rotation clockwise, the radio sensitivity drops
significantly and no stations or normal static can be heard. When I back off
on the gain control, the radio returns to normal. I am guessing that this
sympton (observed on bot radios) is from RF amplifier overload. Is this
behavior normal for a tube radio, and is there a fix? These are the first
boatanchors that I have ever tried to work on, so all of this is a new
experience to me. In all cases, I had the radio hooked up to a 100 ft.
random longwire antenna.

If this behaviour is a symptom on a goof-up on my part in rewiring the sets,
I would appreciate some advice on how to fix the problem.

Steve Burrows