Rich,
Having restored both an NC-183 and a "D", I found that re-capping was
mandatory in both cases. Its not a bad task, given that these receivers
are fairly open and accessible, below the chassis. I found that the
electrolytics in the power supply and the audio stages were either
totally shot or leaking badly. I'd also suggest checking all the tubes.
One or two weak ones can certainly degrade the whole receiver. If an
alignment is found to be necessary, note that the front-end inductors in
these rigs are not easily tuned; they use mechanically repositioned
loops (the book explains all). Finally, I highly recommend running the
set on 110v rather than a higher line voltage. The power xformers in
both my 183's get (I think)abnormally hot above 120v. In fact, I run
the entire collection of boatanchor rigs via one of two 15A variacs
installed in the ops room. Its quite amazing the drop in temp rise of
all the equipment and I'm convinced that their longevity has been increased.