Heathkit SB-401 - CIRCUIT DESCRIPTION; SCHEMATIC DIAGRAM

CIRCUIT
DESCRIPTION
Refer
to
the
Schematic
(fold-out
from
Page
147)
and
the
Block
Diagram
(fold-out
from
Page
124)
while
reading
the
Circuit
Description,
SCHEMATIC DIAGRAM
The letter -number designations on the Schematic
Diagram are used to identify resistors, capac-
itors, chokes, etc, Each of these designations is
related by the first number tothe physical place-
ment of the part in the unit, For example, resis-
tors (and other parts) mounted on the carrier
generator circuit board are designated by num-
bers in a series of 100 to 199, while parts
mounted on the chassis are in a series from
1 to 99, This system of component designation
is
used
throughout
the
Schematic,
Read
the
NOTES
on
the
Schematic
for
further
infor-
mation,
FREQUENCY CHART
To
make
the
various
functions
of
the
Transmitter
easier
to
understand,
a
selected
lower
sideband
frequency
of
3,895
megahertz
will
be
used
when
tracing
through
the
circuit
in
this
Description,
All
switches
are
shown
in
their
fully
counter-
clockwise
positions
on
the
Schematic,
The
Fre-
quency
Chart
lists
the
various
frequencies
tiat
will
be
found
throughout
the
Transmitter,
The
first
line
contains
the
frequencies
referred
to
in
this
Circuit
Description,
FREQUENCY CHART
CARRIER
GENERATOR
OUTPUT
CRYSTAL
FILTER
(FIXED)
LMO
(BETWEEN
5 AND 5,5)
105
5.1
5.3
5.3
Ded
5.4
5.3
5.3
5.4
Frequencies In Megahertz
HHATHEIT® id
BANDPASS
COUPLER
FREQUENCY
(BETWEEN
8,395 AND
HETERODYNE
MIXER OR
TRANSMITTED
SIGNAL
FREQUENCY
HETERODYNE
OSCILLATOR
FREQUENCY
(CRYSTAL
FIXED)
12,395
15,895
22,895
29,895
36,895
37,395
37,895
38,395
Page 125