[Hammarlund] SP-600 First report, HC-10 question.

[Phil Atchley]

Hi.
That SP600 JX17 and HC-10 showed up at my QTH early this afternoon.  This is
about the 4th SP-600 I've had over the past few years.  Needless to say,
I've been a busy little beaver all afternoon 8^)  It seems that all my BA
"projects" arrive in the summertime instead of the winter like normal folks.
What's wrong with this picture?

Anyway, as the man told me before he came down, it'd be a "project" as it
needed some things done before it could be powered up.  He was right.  While
it wasn't badly "hacked", The leads to all the toggle switches had been
clipped at the switches, 5 tubes (2x 6BA6 and 2x 6C4, 5R4) were missing,
though the shields were there.  He brought me a 5R4 as he'd seen it was out.
I checked my junkbox and I have the others in it.

Apparently the man he'd "rescued" it from had intended to do a restoration,
including replacing the toggles and pulling the front panel but ran into
problems getting a couple knobs off.  After a great deal of struggling I got
the knobs off, pulled the panel and thoroughly cleaned the tuning mechanism
and dials.  The dials looked nice but had a film of dirt.  A damp rag with
NO SOAP OR SOLVENTS brought both dials up to looking like new.  Whatever was
on them wasn't hard to get off.  What was a VERY sluggish and slipping
tuning mechanism now spins like an SP-600 dial should!  I installed brand
new toggle switches from my parts stock for all but the meter switch.  Yes,
they're Radio shack units but I still trust em more than 50 year old
switches! Reinstalled the front panel, knobs etc and quit for the day!

Tomorrow I'll test all tubes, check/clean the turret switches etc, then make
a temporary silicon diode plug-in so that I can slowly bring the unit up to
form the caps, see if the filters are any good and temporally usable.  If it
comes to life I'll do some further testing.

XTAL NOTE:  The man I got this unit from said that the 3.5MHz Xtal was
missing from the unit.  First thing I did after he left was pull the cover
and take a "peek" inside.  The 3.5MHz Xtal IS there and doesn't look like
it's been messed with!  However, that doesn't mean it's any good, but one
can hope.  The 6C4 tube that works with it was missing, hmmm, I wonder?

The ONLY modification that I can see has been done to the unit is the Dial
lock removed and an IF gain pot installed there. Anyone else seen this mod
anywhere?

So far I feel quite good about this set, it's definitely in overall better
shape than some I've seen, though the panel isn't as "beautiful" as some
I've seen.  At least all the correct knobs are there, though I DO need to
get a knob for the IF gain mod.  Hmm, I wonder, red or black ;-)

Power connection.  As with others on the list I see I too don't have the
proper cord.  For temp use while working/troubleshooting I'm considering
making a cord by taking a couple pins from an old octal tube socket and
putting them on a 3 wire cord for "push on" connectors.  Insulate it and
Anchor the cord such that it couldn't pull out and become a safety hazard.

NOW THE HC-10 QUESTION:  The manual shows a tube socket adapter to connect
it to the last IF amplifier of the tube. I could make one of these ok but
can it be connected directly to an IF output jack of a receiver that has
one?  My homebrewed Beacon receiver with 455 KHz IF has a jack I put on it.
I see from the schematic that the input ties directly to the notch filter.
Would connecting direct affect the notch operation?

73 de Phil, KO6BB
DX begins at the noise floor!
k06bb@elite.net
Merced, California
37.18N  120.29W  CM97sh



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