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Heathkit SB-401 - Page 12

Heathkit SB-401
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Gags
eatruxit]
(_)
Connect
the
VTVM
RF
probe
to
pin
E
on
the
top
of
the
carrier
generator
circuit
board.
(_)
Depress
the
key.
This
should
close
both
relays.
(
)
Use
the
alignment
tool
to
adjust
the
balanced
modulator
transformer
for
a
maximum
indication
on
the
VTVM.
Hf
there
arc
two
peaks,
the
peak
that
occurs
with
the
slug
nearest
the
top
of
the
transformer
is
the
correct
one.
(Approximately
|
to
1.5
volts.)
{
)
Open
the
key.
(
)
Set
the
Receiver
and
Transmitter
MODE
switches
to
USB.
(
)
Short
lug
2
(marked)
of
the
MIC
connector
to
the
chassis
with
a
jumper
wire,
or
connect
a
microphone
and
press
the
push-to-talk
button;
then,
with
the
VTVM
still
connected
to
Pin
E,
alternately
adjust
the
CARRIER
NULL
control
and
the
capacitor
for
a
minimum
indication
on
the
VTVM.
(
)
Disconnect
the
VTVM.
(
)
Turn
the
METER
switch
to
ALC.
(
)
Adjust
the
ALC
ADJUST
control
for
a
zero
meter
reading.
(
)
Remove
the
jumper
wire
from
lug
2
of
the
MIC
connector,
or
release
the
microphone
button,
(
)
Return
the
Transmitter
MODE
switch
to
the
CW
position.
NOTE:
When
the
METER
switch
is
in
the
ALC
position
during
transmitter
standby,
the
meter
will
normally
indicate
full-scale
deflection.
DRIVER
(
)
Set
the
DRIVER
control
to
the
first
mark
from
the
fully
counterclockwise
marking
on
the
pancl
as
shown
in
inset
#2.
(
)
Set
the
slide
rule
and
the
LMO
dials
to
zero.
(
)
Insert
the
VTVM
RF
probel
into
pin
2
of
tube
socket
V9.
NOTE:
Leave
the
LEVEL
control
in
the
fully
clockwise
position.
Page
91
(
)
Set
the
FUNCTION
switch
to
the
TRCV
position.
NOTE:
When
you
align
each
driver
and
heterodyne
oscillator
coil
in
the
following
steps,
first
read
the
step
all
the
way
through.
Then,
key
the
Transmitter
and
perform
the
adjustment
with
the
alignment
tool.
Release
the
key
as
soon
as
the
step
is
completed.
Some
of
the
coils
are
on
the
bottom
of
the
chassis,
but
can
be
adjusted
from
the
top
of
the
chassis.
( )
Set
both
BAND
switches
to
3.5.
(_
)
Adjust
the
slug
of
the
3.5
DRIVER
grid
coil
for
a
maximum
indication
on
the
VTVM.
(Readings
of
approximately
1.5
volts
or
higher
are
normal.
A
definite
peak
should
be
obtained.)
(_)
Peak
the
3.5
HET
OSC.
(heterodyne
oscillator)
coil
for
maximum.
( )
Set
the
Receiver
and
Transmitter
BAND
switches
to
7.0
and
adjust
the
slug
of
the 7.0
DRIVER
grid
coil
for
a
maximum
indication
on
the
VTVM.
( )
Adjust
the
7.0
HET
OSC
coil
for
maximum.
(_
)
In
the
same
way,
adjust
the
DRIVER
grid
coil
and
the
HET
OSC
coil
at
each
band
switch
position
14.0
through
28.0.
Be
sure
both
receiver
and
transmitter
band
switches
are
always
set
to
the
same
band.
(
)
In
the
same
way,
turn
the
BAND
switches
to
28.5
and
29.5
and
peak
the
HET
OSC
coil
for
each
band.
(
)
Remove
the
VTVM
probe
from
tube
socket
V9.
( )
Install
the
6CL6
driver
tube
(V9).
The
tube
shield
will
be
installed
later.
(_)
Turn
the
FUNCTION
switch
to
the
TRCV
position.
(
)
Connect
the
VTVM
RF
probe
to
the
bare
wire
connected
between
pins
5
of
tube
sockets
V10
and
Vil
on
the
bottom
of
the
chassis.
NOTE:
Leave
the
LEVEL
control
in
the
fully
clockwise
position.
(
)
Turn
both
BAND
switches
to
3.5.

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