Heathkit SB-10 - Testing and Adjustment

TESTING
AND ADJUSTMENT
)Connect
the
SB-10
to
the companion
transmitter
as described
in
During
the following
test
procedure
and
all subsequent
operation
transmitter
is in
its
SSB
operating mode
and
both
transmitter
and
are set
on
the same
band.
the
preceding
section.
on
SSB,
make sure
the
adapter
band switches
(
)
With
the transmitter
set
for SSB
operation, bothpower
and
plate
switches
on
the transmitter
in the
OFF
position,
and the
transmitter drive
control
full
CCW, select
the 80M
band
posi-
tion
on both
the
transmitter
and adapter
and
set
the
sB-10
controls
as follows:
Sideband
selector
either
UppER
or
CarrierNullA..
fullCCW
"
Audio
Gain
full
CCW
'':
Function
switch
STANDBY
/
Balanced
modulator
5
,''Output...
......
b
.
''
Transmitter
sensitivity
.
full
CCW
(on
rear
,"
Receiver
sensitivity
full
CCW
(on
rear
*
Audio
balance
5g7o
rotation
f
rorn
**
Phase
balance.
. .
25Vo
rotation
from
+This
is
the screwdriver
adjustment
on the
audio and
phasing
deck
nearest
the
left edge of
the
chassis.
+*This
is
the
screwdriver
adjustment
on
the audio and
phasing
deck nearest
the
center of
the
chassis.
(
)
Place
the
power
switch
on
the
transmitter
in
the
heating
in
the SB-
10
and make
sure
all the
tubes
switch
in
the OFF
position.
(
)
If no
abnormal
operation
is
noted in
the
preceding
step,
turn
the SB-10
function
switch
to
"MANUAL".
The
relay
should
close and
the
"R;lative
power
output"
meter
may
read
slightly
upscale.
Once
again,
check for any signs
ofoverheating
or extessive plate
dissipa-
tion in
any
tube,
as indicated
by the
plate
showing
a red
glow.
If
any signs
of abnormal
operation
are
apparent,
return
the function switch
to STANDBY
and
rectre-ck
your
work.
(,
)
Rotate
the
drive
control
on
the transmittel
about
one-quarter
turn
from
the extreme
CCW
position
and tune
the
transmitter
driver
output
circuits
for maximum
SB-
10
meter indication.
(')
Tune
the
balance
modulator
control on
the adapterfor
maximum
meter readinEand
then
tune
the
output
control
for
maximum
meter reading.
Finally,
adjust
the slug
in"coil
Ll
on the
RF sub-chassis
for
maximum SB-l0meter
reading.
Once Llls
so adjust-ed,
it
rvill need no
further
adjustment.
(
'
)
Notice
that,
as
the transmitter
drive
control is
advanced
in
a
CW direction,
a
point
is reached
where
increased
drive
does
not
produce
an increase
in SB-10
meter reading.
In
all cases,
the
transmitter
drive
should
be setjust below
thispoint
forproper
operatiori.
After
making
all
the
preceding
adjustments,
the SB-10 meter
should
be reading
in
the
upper
third of
the
scal
e.
, )
Return
the SB-10
function switch
to STANDBY. Now
place
both
the transmitter
and adapter
band
switches
in
the 40M
position
and
repeat
the
three
preceding
steps,
this
time
finally
adjusting
the slug
in coil L2
on theRF sub-chassis
for
maximum meter
reading,
Using
thL
same
procedure,
adjust L3
for maximum indication
on 20M, L4 for
maximum indication
on
15M,
and L5 for
maximum
indication
on
10M.
The
maximum
indication
on l6M
may be less
than
for
the lower
bands but this
is normal.
LOWER
apron)
apron)
full
CCW
full
CCW
ON
position.
Check
for
any signs
of over-
are
lighted.
Leave
the
transmitter
plate
+*
.-.,
i
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53