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Heathkit SB-401 - Page 25

Heathkit SB-401
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Page
100
(
)
-_~
—
-_~
~—
—
od
—
—
Adjust
the
DRIVER
control
for
a
maximum
indication
on
the
VTVM,
Adjust
the
FINAL
control
for
a
maximum
indication
on
the
VTVM,
with
the
LOAD
control
set
at
the
50
Q
position,
Using
an
insulated
screwdriver,
adjust
the
Neutralizing
Capacitor
for
a
minimum
indi-
cation
on
the
VTVM,
Readjust
the
FINAL
controls
for
maximum
indication
on
the
VTVM,
Readjust
the
Neutralizing
Capacitor
for
a
minimum
indication
on
the
VTVM,
Turn
the
FUNCTION
switch
to
the
OFF
position,
Unplug
the
Transmitter
line
cord
and
wait
approximately
5
minutes
before
continuing,
Refer
to
Figure
2-3
(fold-out
from
Page
94)
for
the
following
steps,
CAUTION:
Be
sure
to
use
a
screwdriver
with
an
insulated
handle
to
discharge
the
high
voltage
capacitors
in
the
next
step,
( )
—
—
Discharge
the
high
voltage
capacitors
by
shorting
the
lower
lead
of
feedthrough
capacitor
Q
to
the
chassis
with
a
screw-
driver,
Be
sure
to
touch
the
metal
blade
of
the
screwdriver
to
the
chassis
first,
then
to
the
capacitor
lead,
Repeat
this
step
a
number
of
times
to
be
sure
the
capacitors
are
completely
discharged,
On
top
of
the
chassis,
connect
the
lead
of
feedthrough
capacitor
Q
to
lug
2
of
coil
TB
(S-1).
Bend
the
lead
of
the
capacitor
carefully
to
prevent
breaking
the
ceramic
form,
HEATHEIT®
(
)
On
the
bottom
of
the
chassis
connect
a
680
2
(blue-gray-brown)
resistor
from
lug
3
of
terminal
strip
P
(S-3)
to
the
center
of
the
bare
wire
connected
between
lugs
3
of
tube
sockets
V10
and
V11
(S-1),
Refer
to
Figure
2-4
(fold-out
from
Page
94)
for
the
following
two
steps.
(
)
Install
the
final
amplifier
rear
plate
on
the
final
amplifier
enclosure,
using
#6
x
3/8"
sheet
metal
screws,
(
)
Install
the
final
amplifier
top
plate
on
the
final
amplifier
enclosure,
using
#6
x
3/8"
sheet
metal
screws,
IMPORTANT:
Do
not
key
the
Transmitter
for
more
than
30
seconds
at
a
time
until
after
you
have
completed
the
Final
Transmitter
Adjust-
ments,
FINAL
BIAS
(
(
(
)
~
—
Connect
the
50
2,
100
watt
dummy
load
to
the
ANTENNA
connector,
Plug
in
the
Transmitter
line
cord,
Remove
the
6CL6
driver
tube
(V9),
Set
the
METER
switch
to
PLATE,
Place
the
BAND
switch
in
the
3,5
position,
Turn
the
FUNCTION
switch
to
TRAN,
Allow
a
few
minutes
warmup
time,

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