Operating instructions
Section lll.
ALINEMENT
PROCEDURES
92.
Test
Instruments
Required
for
Alinement
a.
Signal
Generator.
The
signal
generator
should
be
an accurately
calibratecl
instrument
producing
modulated
and
unmoclulated
r-f
sig-
nals,
such
as
Signal
Generator
TS-b8g
.U
or
RF
Signal
Generator
AN,,'URII-25.
The
fre-
qllency
range
must
extend
from
400
kc
to 2b
mc.
The
alinement
freqnencies
are
shor,vn in
paragraphs
94
through
96. If
necessary,
the
second
harmonic
generally
can be
used rvhen
the fundamental
is not
available.
The
genera-
tor should
have
an output
of
at least
5,000
irv
for
best
results
in
alining
the
r-f,
h-f
oscillator,
and i-f circuits.
Frequency
calibration
of the
signal
generator
is
extremely
important
to
in-
sure
that
the
receiver
dial
calibration
will
he
correct.
b.
Output
Meter.
The
output
meter
should
respond
to audio
frequencies
and
shoulcl
pro_
vide
at least
half-scale
deflection
for
2.b
volts
(approximatell'
10
mr,v).
It
should
have
a
600-
ohm input
impedance.
Use
Output
Meter
TS_
585/U
(or
an
equivalent
meter),
set
at
600
ohms.
c.
Freqtrencll
Meter.
When
a highly
accurate
signal
generator
is
not
available.
use
a
fre-
quency
meter
to check
the
accuracy
of
the
gen_
erator.
Frequency
Meter
Set
SCR-211
is
suit_
able.
d.
Heaclset
or
Pertttanent-Mo
qttet
Lottcl-
speuker.
The
integrally
mounted
loudspeaker
or
the
headset
suppliecì
may
be
used for
rouglr
alinement.
e. AIínement
Tools.
A suitable
alinement
tool,
supplied u'ith
the
receiver,
or
an insulated
screw
driver
and
insrilated
nut
drir.'er
are
re-
quired.
93.
Colibrotíon
of
Signol
Generotor
When
the signal
generator
calihration
is
nct
acceptable,
accllrate
alinement
of the
h-f os-
cillator:
in
the
receiver
requires
the
use
of
a
freqnencl'
meter
to check
the signal
generator
setting.
as follou's
:
a. Place
the
generator
and
the frequencl.
meter
near
each other.
b.
Turn on
both
equiltments
and allorv
them
to warm
up for
at least l5
minutes.
c.
Calibrate
the
frertuency
meter
according
to the
instructions
fnrnishecl
n-ith
that
unit.
d,.
Attach
a
piece
of
u'ir.e
to
the
signal
gen-
erator
output
connectiotr
anil
place
the u'ire
near
the frequenc;'
meter
antenna.
e.
Set
the
meter
to
the
exact frequency
at
which
the
generator
is
to be
used.
l.
While
listening
to
the heaclset
connecred
to
the frequency
meter,
tune
the
genefator
to
zero
beat
with
the
meter.
The
sigtral
generator
is
nolv
set for
the frequenc;,
desired.
.q.
Turn
off
the frequency
meter
and
remove
the wire
attacheci
to the
signal
generator
out-
put
connection.
9+,
l-f Alinement
Procedure
(figs.
38,
39,
and
40)
Nolc.
Keep
the
oLrtput
reading
at
10
mrv
durine
these
tests.
cr.
Set
the
output
meter
to
600 ohms
and
con-
nect
it
to the
receiver
PHONES
connector.
Con-
nect
a suitable
heaclset
into
the
other
connector
for
listening plìrposes.
b.
Set
the signal
generator
to
485 kc,
moclu-
lated
30
percent
at
400 c-vcles,
ancl
connect
its
output
through
a .05-1,f,
or larger,
blocking
capacitor
to
the
signal
grid
of the
seconcl
i-f
amplifier
tube
(pin
6 of
Y5).
c.
Set
the receiver
and
power
suppll,
frotrt
panel
controls
as follou,s:
Con t rol
OUTPUT
HIGII-LO\\.
su'itch
(S4)
PHN.-C.W.-NET-CAL.
s\îitch
(
52
)
R.F.
GAIN
control
(IÌli2)
SPI,IAKER
ON-OFF
srvitch
(5102)
BAND
S\\r.
srvitch
(S1)
MANUAI,.PRESET
TUNING
controì.
A.F.
GAIN
(R19A
and
R19B)
PO\\-ER
SELECTOR
srvitch
(s101).
PO\\'ER
ON-OFF
swirch
(S1o:l)
Set ting
HIGH
PHN.
Ilaximurn
OFF
Band
2
lJ rrrc
Ad.iusted
to r.ead
to |0 rlrrv on
olttÌltì1
nl(,î(,t
lIodc,
of
oìrer':rtion
rrserl
ON
d,
Allou'
the receiver-
ancl
l)()\\-el'
srrpltlr-
to
\varm
up for
approxinriitelr-
.l
ntinutr:s
ltefore
making
an;"'
acl.jLrstulenîs.
Ilt,
srrre
that
no
out-
side
signal
is
contin!'
in thr.oLrgh
the
antenna
circuit.
Acì.iust
filirrtrent
voltage
control
R116
.4.GO
313A
7?