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bottom
uiew,
showing
typical
]|
]
]
]
]
x
'
Pr`
`71
Q L
O
22
SecaOna
.LUBRICAT10N
35.
Generol Lubricotion
lnstuuctions
a.
Several
factors
determine the
frequency
with
which
parts
in
the signal generator
need
to
be
lubricated.
These
factors
are-.
(1) After
a
certain length of
time,
most
lubri-
cants
become wax-like
and
cake up
in
spots
so
that
they
will not
give
the
proper
lubrication.
In these
c ses,
the
old
lubricant
should
be
cleaned off and
new.
lubricant
applied.
(2)
The signal
generator
may be operated
in
a
location
where
extreme
temperature
changes
occur;
the
lubricant
then
will
be
hard
because
of low
temperatures
when
the
signal
generator
is not
in
operation
and
extremely soft
or liquid
when
the
signal
generator
is
operating
and
the
temperature
risos.
\{here the
tempera-
32
ture
change
is great,
the
condition
of
the
lubricants
must
be
inspected
frequently.
In some
locations,
the
foreign
materials
present
in
the
air, such
as
dirt,
sand,
smoke,
metal
filings, or
g ses,
may
enter
the
signal generator
and
mi-x
with
the
lubricant
and
form
a
grit,
or
decompose
the
lubricant.
If
grit
is
formed,
it rvill
act
as
an
abrasive
and
cause
serious
wear.
The
old
lubricant
should
be
cleaned
away
thoroughiy
with
solvent
(SD)
and
fresh lubricant
applied
frequently.
Although
the
signal
generator
is
protected
against
humidity,
a
certain amount
of
moisture
may
enter
and injure
the
moving
parts.
tr4oisture
condensation
is
preva-
Ient
when
the temperature
drops
quickly
and the
relative
humidity
is
high.
If
(3)
(4)
@
Y
=]
O
a
=]
k
t
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of reacrtance
tube V5,
R49
is
the
fi'ont
panel
control
which
sets
the deviation
level of the r-f oscillator.
c.
Tube
V9,
a
6C4
triode,
is r.'onnected
as a
calho
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57.
l-F
Attenuotor
(fig.
z7)
tz. A
simpiifiecl
scirematic
ciiaglam
of
tire
i-f
attenuator
is shorrn
in
figure
27.
Any voltage
supplierl
b1-
the
i-f
output
stage
passes
through the
i-f
attenuator
before
reaching
the
i-f
oulput,
cable.
The
attenuator
is
made up
of
trro switches
and a
resistor
pacl
rr-hich
allows
20-db
(voltage
ratio
of
10
to 1) attenuaticn
steps
betrveen
the
contacts in
each
position
of
the
If'
\{ICROVOLTS
srvitch.
The
purpose
of
the
pad
and
srvitch
54
is
to
atten-
uate
the input signal
and
provide
a
constant
irlpeclance
to
the
output
cable.
The
pacl
consists
of
resislors
R76 through
R83.
Wren
the Itr'
\IICRC\-OLTS
sii,itch
is turned
to
the
1.0 YOLT
position,
srritch
S5,
rr,hich
is
operated
by
a
cam on
54. alloivs
the direct
output
of
1
volt from
the
i-f
amplifier
stage
to
be
supplied
to
the
i-f output
cable.
Resistors
R75 and
R103 are sq,itched
into
the attenuator
orrtput
circuit in
the 1.0
YOLT
position
to
maintain
thc
necessary
orrtput
im-
pedance.
CR2
1N21B
D.
The
output
from
the
attenuator
passs
thlough
a sholt
length of
coaxia,l
cable
to
jack
J6
oa
the
front panel,
and
then through
the
flont
panel
tlirough
a
cablc
r.hich
is
permanently
con-
nected.
The i-f
oulput
cable is
terminated
by
resistor
R84.
Looking
into
the
generator,
a
25-
ohm
output
impedance
is
seen.
Connection
is
nrade
from
this
cable
by
means
of
ailigat,or
clips.
58.
R-F
qnd
l-F
Output Metering
Circuits
tr'igure
28
shows,
in
a
simplified
form,
the
metering
circuit t hich
me sures
the
voltage
inputs
to the
r-f
and
i-f
output attenuators.
Depending
on
rhe position
of
OPERATION
su'itch
51,
either
the r-f or i-f voltage
is measulcd.
s,.
In
the IF
position
of 51,
a
portion
of
the
i-f
attenuator
inpub voltage
is
rectified
bv
crystal
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2o00r--Gu|{*--r-1?ooo
+,,*+
17
TM1257-54
3996340-56(Face p
Vi V2 V7 Ve v9
5CCI .9uu
E
1 500 0
P9T VVV T
]~u
~~~v
(equipments
after
seri,al No.
110).
TO LUG:
Si SECT:
P
\
VVV \
V 2
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