I have just gone through rebuilding two SP-600's, neither
is quite perfect yet, but close. I would like to hear the
experiences of others: problems encountered, etc.,
especially with dial calibration. My receivers are a JX-21
or possibly a JX-26 (top cover was missing) and a JX-17. The
JX-21(?) was built about 1955 judging from the dates marked
on some components. It is an R-274C built on a 1954
contract. The JX-17 appears to have been rebuilt at a
military shop some time in its life (all ceramic caps)and
has a date late in 1955 stamped on the inside of the front
panel. I've had both receivers for many years but have
recently decided to get them as close to mint performance as
I can.
I can find no specification on dial accuracy for either
model. I beleive I saw a spec of 0.25% in one Hammarlund ad,
this is not really a very tight spec and both receivers make
it. Should it be better? The design of the main tuning
capacitor is such that its adjustable and I understand that
each capacitor went through a factory adjustment proceedure
to get each section to match specs. Does anyone know
anything further.
BTW, I have visited the usual SP-600 sites on the web. In
particular the "Hammarlund Historian" and Andy Moorer's
site, both of which are quite helpful. I also obtained all
the manuals and othere material available from these sites
and from "BAMA". One of these guys is sittign about 8 feet
from me right now glowing at me:-)
This group seems to be mostly FS and WTB advertising so I
hope this post is still on topic here.


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Richard Knoppow
Los Angeles, CA, USA