Need Help on SB-303/313 hybrid

[Peter Havens]

Great Greenies!

     Hopefully someone can help me out on this project I'm attempting. In
trying
to acquire a SB-313 for "shortwave-band" listening, I became increasingly
disinchanted in the hopes of finding one at a reasonable price. In
addition, I really
wanted to couple it with an old '650 display that I have, but of course
the '313
lacks the necessary LMO and etc. outputs to do this, without certain
modifications.
So, when I spotted a cherry '303 at an estate auction for 50 bucks, I
thought why
not do some mods on the 303, to kind of make it into a super 303/313
hybrid: it
has the LMO, HFO, BFO outputs, and the HF/VHF1/VHF2 switch could also
serve as
a 3-position selector for different antennas. The only really big
difference is
of course the crystal and het. osc. boards.
     So I bought it, ordered new crystals from ICM (International Crystal
Manuf;
their prices were, I thought, quite reasonable) for the band segments
that I
wanted to cruise, and replaced same. Now here is where I am stuck: I can't
seem to get most of the coils on the het. osc. board to do their thing,
that is,
oscillate. I am assuming that the coils just won't work beyond a certain
deviation from their designed range of frequency. All 5 coils carry a
different
part number: 40-978,-979,-980,-981, and -982. I am therfore assuming that
the
SB-313 has a different series of het.osc. coils.
     So, my request(prayer) is this: could anyone check their '313 manual
to see
what part numbers are used for the het.osc. coils. Also, a partial
schematic of
the whole switch board would be usefull too, as I suspect that the mica
caps. that
are paralleled with the coils might be of different values between the
two rigs as
well.
     Anyway, for now, I'm kinda stuck! HELP!

                                               Still a little Green
behind the ears,
                                               Peter Havens
                                               KA2SQJ

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