Heathkit HR-10B - Replacement Parts Price List

Page
30
ALIGNMENT
IF
TRANSFORMER
ALIGNMENT
AND
METER
ZERO ADJUSTMENT
Equipment
Required:
An
amplitudf!
modulated
RF
signal
generator
and an
Ac;
voltmeter,
,,
( )
Set
all
front
panel
controls
as
follows:
AF
GAIN
RF
GAIN
BFO TUNE
BAND
Switch
MAIN TUNING
ANL
AVC
BFO
CAL
· STBY-REC
12
o'clock
Maximum
clockwise
12
o'clock
80
meters
3.5
me
OFF
OFF
OFF
OFF
REC
( ) Connect a
jumper
wire
from
lug 9 of tube
socket
V2
to
lug
1 of
terminal
strip
Q.
This
disables
the
oscillator
for
IF
trans-
'
former
alignment.
( ) Connect one
.lead
of
the
AC
voltmeter
to
lug 1 of
Speaker
jack
BA
on the
rear
apron.
Connect
the
other
test
lead
to ground.
( ) Make
sure
that
the
speaker
is
still
connected
to
the
Speaker
jack.
( ) Connect
the
positive
or
hotlead
of the
signal
generator
to
the
center
lug
of the ANTenna
connector
on
the
rear
apron.
( )
Turn
all
of
the
equipment
on and
let
it
warm
up
for
approximately
30
minutes
to
stabilize
all
circuits.
( )
Place
the
meter
on
the
3
or
5
volt
range
and
set
the
generator
for
a high output
level.
The
output of the
generator
should be
re-
duced
as
the
alignment
procedure
increases
the
sensitivity
of the
Receiver
to
keep
the
meter
reading
at
approximately
1-1/2
volts.
( )
Start
alignment
of
the
IF
transformer
by
adjusting
the
signal
generator
for
maximum
indication on
the
meter.
The
generator
read-
ing
at
this
time
may
be
slightly
above
or
below the 1682 kc
IF
frequency.
( ) Adjust
the
-bottom
slug
of the IF
trans-
former
T3'
for
maximum
meter
indication.
Then
adjust
the top
slug
of
T3
for
a
maxi-
mum
indication.
Proceed
to
transformer
T2
and
adjust
the
bottom
slug
for
a
maximum
indication, then
adjust
the top
slug.
( ) Adjust the top
slug
of T1
for
a
maximum
indication, and then
adjust
the
bottom
slug.
( ) Adjust the
signal
generator
frequency
for
a
maximum
meter
indication.
Then
repeat·
the
above
IF
transformer
alignment
steps.
( )
Repeat
the
entire
procedure
described
above,
each
time
adjusting
the
signal
gen-
erator
until
further
adjustment
does
not
cause
an
increase
in
meter
reading.
Refer
to
Figure
2
for
the
locations
of
the
transformers
called
for
in the following
steps.
( )
Place
the
BFO
switch
in
the
ON
position.
Turn
the modulation
switch
on
the
signal
generator
to off.
Turn
the
slug
in
the
BFO
coil
until
you obtain a
zero
beat.
Be
sure
that
the BFO
tuning knob
is
in
the
12
o'clock
position
and
that
the
signal
generator
is
peaked
for
maximum
voltage.
reading.
( )
Rotate
the BFO
tuning knob
each
side
of
the
12
o'clock
position.
For
the
same
amount
of
rotation
in
each
direction,
the
tone should
be
the
same
frequency
except
at
the
extreme
.
clockwise
and
counterclockwise·
positions,
where
there
is
nonlinearity
of the
variable
capacitor.
If
the
:tone
is
not
the
same
fre-
quency,
readjf!flt
the BFO
coil.
\
( )
Turn
the
BF6
switch
to
OFF
and
turn
the
modulation of the
generator
on.
( )
This
completes
the
alignment
of the IF
stages
in
your
Receiver.
Disconnect
the
test
equip-
ment
and
remove
the
jumper
wire
from
lug
9
of tube
socket
V2
to lug 1 of
terminal
strip
Q.
Temporarily
place
a
short
from
the
center
lug
of the ANTenna
connector
to
ground
with
a
screwdriver.
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