[Hammarlund] Hello, and ID help request

[John M. Trindle]

I'm new to the list, and currently plowing through back archives.  I've
got an HQ-129-X which is working OK, though I'm sure it could be renewed.
I've also got an older Hammarlund which I haven't quite ID'd.

I thought it was a Comet Pro, and downloaded a scan of the manual. Almost
everything matches except that a tube listed as a "47" in the manual seems
to be a 2A5 on the chassis.  I would be sure except that I dropped the
tube last night onto the concrete garage floor, shattering it beyond
readability.  It has 6 pins on the bottom where the 47 has 5.  I'd like
help IDing this so I can get the right schematic.

Even with 8 working tubes this radio makes no sound, except some knob
noise.  Within a minute or two of power-on, the 80 tube glows brightly and
self destructs.  I have destroyed 2 of these tubes with exactly the same
result, and have one spare left.  The 80 seems to be a power rectifier
tube and perhaps there's a short somewhere.  However, my electronics
knowledge is basic (kit assembly / minor soldering) so I'm not much at
running down an issue (especially with the wrong schematic).  I want to
repair this radio for sentimental reasons, as I believe it was my recently
deceased grandfather's first receiver.  I would also like to get some coil
sets for it.  The only one I have is the "CC" set.

The 129-X is working well enough for me to start my SWLing and to try to
copy some code.  I do have some issues with it....

1) I have a voltage between the ground screw and ground.  In my case, it
seems to be about 50VAC with very low current.  The chassis itself does
not show this voltage, and grounding the ground screw doesn't seem to
change the received signal strength.  Is this a safety issue, and should
it be tied to ground, or to the unused Antenna lead?  I am using a single
"random" length wire antenna, currently about 15m run around the inside of
my garage.

2) The Noise Limiter just makes things more distorted.  Things sound OK
without it, though.  Is this limiter just for CW or is it supposed to help
voice reception?

3) The band select knob is flaky, in that sometimes a band doesn't work at
all.  I assume this needs cleaning?  If I wiggle the knob or switch in and
out a few times, I can usually get the band working.

4) There is a Q Multiplier add-in, an external box Heathkit.  I've been
using this strictly for CW reception to place the audio signal in the Q's
filter resonance peak.  That seems to help but it's a pain to set up,
meaning I miss a lot of code twiddling knobs.  This device has a tube-type
socket plug-in and an RCA plug on the back of the 129X.  Any pointers to
proper operation?

Thanks for any help!

...John Trindle

-- 
John M. Trindle
http://i.am/jtrindle
"If it can't be expressed in figures, it is not science,
it is opinion. - Robert A. Heinlein"