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l1odel654A
levels,
and
ie
shown on
DIFFEREN·
sed for
the
:hematic
for
lot
zero,
the
circui
t.
TORS.
d
to ground,
.. The
signal
cover. The
nand
lubri·
Service Note
.ube 2A Or
)-0300
.
ake
nd·
be
IS.
:ed·through,
ing
on these
damage to
ng iron with
t sink
(long
!ezers, etc.)
component
ectly
on
the
:
lead. If a
faulty, clip
remove the
\T
)M
ro
leating
the
e soldering
allic object
Model
654A
d.
To
mount
a
new
component, shape
the leads
and
insert them
in
the
holes.
Clip a
heat
sink on
the
component,
heat
with
the
soldering
iron,
and add
solder as
necessary to
obtain a good electrical
connection.
5.101. SERVICING ROTARY SWITCHES.
5.102.
The
Model
654A con
tains two rotary type
swi
tches:
FREQUENCY RANGE
and
the
ATTENUATOR.
When
working
on
these
swi tches, observe
the
following
rules:
a. Use
a
low heat
(25 to 50 watts) soldering
iron
with
a small
tip
.
b. When replacing
them
as
nearly
possible.
components,
to their
attempt to
original
alignment
dress
as
c. Clean excessive
flux
from
the
connection and
adjoi
ning
area.
d.
After cleaning
the
swi
tch,
apply a
ligh t
coat of
lubriplate
to
tile
switch
detent balls. DO NOT
apply
lubricant to
switch contacts or allow
lubri·
cant
to
contaminate components.
""
i.
H<
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II!
j
3
0
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0
~
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2
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0"
"",
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i~
,&
.".,
,
"'
>-
0
z
I_
t-
[
-
1
~
-
3.4
5
- '
..
I
I--
,.250
,"
I..--_ _
I
I-:
D
L
-__________
+-_____
dTl
l--------.;~'.,
....
TOP
COV
ER
6'
H A
-
e
·
·
J 6)
~
Section V
e. To eliminate excessive contact wear and oxidation,
the
contacts
may be lubricated with Electrolube
2G,
-hp- Part No.
5060-6086.
Only
a very small
amount of
lubricant is necessary. Note:
Electro·
lube 2G
will change
to
a
reddish brown
color with
time; however,
the
lubricating properties
are not
affected.
A more detailed description on how to
apply Electrolube
2G
is
available at
no
cost from
your
local Sales and
Service
Office. Ask
for Service
Note
M45B.
5-103. SERVICING TUNER ASSEMBLY.
5-104.
When
replacing
the tuning
capacitor,
C J,
make
certain
that the tuner
coupler and
the frequency
dial shaft
are
aligned to prevent binding
of
the FREQUENCY Dial
or
VERNIER
control.
If necessary, remove the
frequency
dial
knob, frequency dial,
and
loosen the tuner drive
assembly
(casting
and spur gears)
retaining
screws;
then align tuner
coupler and frequency
dial
shaft.
Tighten retaining
screws
after
tuner
coupler and
dial
shaft are aligned.
NOTE
For correct alignment,
refer to
Frequency
Dial
Calibration,
Paragraph
5-52.
"'
>-
o
' "
N
..
'-"--------
'.6- -
~-----------
7.4
-------~
~------------
8.1
---
BOTTOM
COVE
A
6~3·
B
-1636
Figure 5-17. Alignement Access Covers for Models 651
B,
2A, 3A, 4A
5-25
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