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Heathkit SB-401 - DRIVER

Heathkit SB-401
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Page
98
(_
)
Adjust
the
balanced
modulator
transformer
T1
for
a
maximum
indication
on
the
VTVM.
There
are
two
peaks:
the
peak
that
occurs
with
the
slug
nearest
the
top
of
the
can
is
the
correct
peak.
(Approximately
|
to
1.5
volts.)
(
)
Open
the
key,
Rotate
the
LEVEL
control
fully
counter-
clockwise,
Set
the
MODE
switch
to
USB,
(
)
Short
lug
2
of
MIC
connector
FL
to
the
chassis,
using
a
jumper
wire,
or
connect
a
microphone
and
press
the
push-to-talk
button,
This
should
again
close
both
relays
(See
Page
95
for
microphone
connection),
Adjust
the
CARRIER
NULL
control
and
ca-
pacitor
for
a
minimum
indication
on
the
VTVM,
(
)
Turn
the
METER
switch
to
ALC,
(
)
Adjust
the
ALC
ADJUST
control
for
a
zero
meter
reading,
NOTE:
en
the
METER
switch
is
in
the
ALC
position
during
transmitter
standby,
the
meter
will
normally
indicate
full-scale
deflection,
( )
Return
the
MODE
switch
tothe
CWposition,
(
)
Set
the
FUNCTION
switch
to
STBY,
“~~
OO
—
ee
-_—
~~
DRIVER
( )
Set
the
DRIVER
control
to
the
first
mark
from
the
fully
counterclockwise
marking
on
the
panel,
Set
the
LMO
dial
to
zero
(counterclockwise),
Insert
the
VITVM
RF
probe
into
pin
2
of
tube
socket
V9,
“—~
=
—
~~
(
)
Set
the
FUNCTION
switch
to
the
TRAN
position.
(
)
Rotate
the
LEVEL
control
fully
clockwise,
NOTE:
When
you
align
each
driver
and
hetero-
dyne
oscillator
coil
in
the
following
steps,
first
read
the
step
all
the
way
through,
Then
key
the
transmitter
and
perform
the
adjustment,
Re-
lease
the
key
as
soon
as
the
step
is
completed,
( )
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,)
Set
the
BAND
switch
to
7,0
and
adjust
the
slug
of
the
7,0
DRIVER
grid
coil
for
a
maximum
indication
on
the
VTVM,
_
~—
Gag
Hearuxit
(
)
Repeat
this
same
procedure
for
each
set-
ting
of
the
BAND
switch
through
28.0
by
adjusting
the
corresponding
DRIVER
grid
coil
for
a
maximum
indication
of
the
VTVM,
Return
the
FUNCTION
switch
to
STBY,
( )
( )
Rotate
the
BAND
switch
to
3,5.
(
)
Rotate
the
LEVEL
control
fully
counter-
clockwise,
(
)
Connect
the
VTVM
RF
probe
to
the
bare
wire
connected
between
pins
5
of
tube
sockets
V10
and
V11
on
the
bottom
of
the
chassis,
Install
the
6CL6
driver
tube
(V9),
The
tube
shield
will
be
installed
later,
NOTE:
Some
VTVM
RF
probes
may
loada
circuit
and
cause
faulty
tuning,
To
check
for
this,
first
adjust
the
coil
for
a
maximum
VT
VM
reading
as
directed
in
the
step.
Then
disconnect
the
RF
probe
from
the
Transmitter,
set the
METER
switch
to
GRID,
and
readjust
the
coil
for
maxi-
mum
indication
on
the
panel
meter,
(Turn
the
LEVEL
control
slightly
counterclockwise
if
the
meter
reads
off-scale,)
(_
)
Turn
the
FUNCTION
switch
to
the
TRAN
position
and
key
the
transmitter.
(
—
Rotate
the
LEVEL
control
fully
clockwise,
Adjust
the
slug
of
the
3,5
PLATE
driver
coil
for
a
maximum
indication
on
the
VTVM.
(Readings
of
35
volts
or
higher,
should
be
obtained,
depending
on
band,)
Readjust
the
slug
of
the
3,5
GRID
driver
coil
for
a
maximum
indication
on
the
VTVM,
od
~~
—
o_o
~~
Repeak
the
3,5
HET
OSC
coilfor
maximum,
-_
~
Place
the
BAND
switch
in
the
7,0
position,
_~
—
Adjust
the
slug
of
the
7,0
PLATE
driver
coil
for
a
maximum
indication
onthe
VT
VM,
~~
Readjust
the
slug
of
the
7,0
GRID
coil
for
a
maximum
indication
on
the
VTVM,
_~
~
(_
)
Repeak
the
7,0
HET
OSC
coilfor
maximum,
_
~
Repeat
this
same
procedure
for
each
set-
ting
of
the
BAND
switch
through
28,0
by
adjusting
the
corresponding
PLATE
and
GRID
driver
and
Het
Osc
coils
for
a
maxi-
mum
indication
on
the
VTVM,
Set
the
BAND
switch
to
29,0,
Adjust
the
DRIVER
control
for
a
maximum
indication,
~~
—

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