Operating instructions

Section
I l.
88.
Generol
Precoutions
Whenever the equipment
is to be serviced,
observe
the following
precautions
:
a.
When
making
measLlrements
s'ith
the
power
on, be careful
not to touch the
incoming
power
terminals.
Severe
shock
or bttrn may be
caused by
low
voltages
if
conditions
are
such
that current
flow
is high.
b. Before touching any
part
in the set after
the
power
has been
removed,
discharge
capaci-
tors C114
and C118
in the
power
supply
and
capacitor C37
in the
receiver.
c.
Careless
replacement
of
parts
often
makes
new
faults inevitable.
Note the
following
points:
(1)
Before a
part
is unsoldered,
note the
position
of the
leads. If the
part,
such
as
an
r-f or
Power
transformer,
has
a
number
of
connections,
tag eactr
of
the
leads to
it.
(2)
Be
careful
not to damage
other
leads
by
pulling
or
pushing
them out
of the
way.
(3)
Do not allow
drops
of solder
to
fall
into the
set; they
may
cause short
circuits.
If solder does
drop
into the
set, remove
the
solder
immediately,
because
it is very
often
forgotten.
(4)
Keep the
hot solclering
iron away
from
other
parts;
excessive
heat may
dam-
age them.
(5)
A carelessly
soldered
connection
may
create a
new fault.
It is very
impor-
tant to
make a
rvell-soidered
joint;
a
poorly
soldered
joint
is
one of
the most
difficult
faults to
find.
(6)
When a
part
is replaced
in r-f or
i-f
circuits,
place
it in exactly the same
position
as the original
one. A
part
which has the same electrical
value,
but
different
physical
size,
may
cause
trouble in r-f circuits. Give
particular
attention to
grounding
when
replacing
a
part.
IJse the
same
groLlnd
point
as
in
the original wiring.
Failure
to ob-
REPAIRS
serve these
precautions
may
result
in
decreased
gain,
oscillation of the cir-
cuit, or
increase in
the
radiation
of
the h-f oscillator.
89.
Replocement of
Ports
o.
Most
of the
parts
in Radio
Receiving
Set
AN/GRR-5 are readily accessible
and easily
replaceable,
if found to be
faulty. When the
BAND
SW. switch
(S1)
in
the
receiver requires
replacement, mark the
wires connected to the
switch carefully
with tags or other
devices
to
avoid errors
in connection
when a
new
switch
is
installed. Be
equally
careful
when replacing
PHN.-C.W.-NET-CAL.
switch S2. \Yhen
POWER
SELECTOR
switch 5101
or
POWER
ON-OFF switch
3103
in the
power
supply re-
quires
replacement,
follolv the same
procedure.
Follow this
practice
when
replacing any com-
ponent
rn'hich has
nnmerolls
connections.
b.
When
replacing
one of
the transformers
T1 to
T8 inclusive
in the
receiver,
be extremely
careful
when
inserting tools
through
the
band-
switch
assembly.
An alternate
method of
gain-
ing
access
to the
transformers
is
to
remove
the
band su'itch
by removing
the front
panel
(par.
91), and
then
removing the 6 screws
and
lock-
washers
holding the
band switch.
90.
Refinishing
Instructions
for
rustproofing
and touch-up
painting
are
given
in
paragraph
39.
Instruc-
tions
for refinishing
baclly
marred
panels
or
exterior
cabinets are
given
in TM 9-285t.
91.
Disossembly Procedure
(fig.
a6)
a.
Gear
Assentbly. Loosen the
coupling at
the back
of the
gear
assembly
by
loosening the
two setscrews,
using: the
wrench
supplied,
and
processed
as follows:
(1)
Remove the three
cap and chain as-
semblies from
the three
connectors
and remove the
three
locking
rings
and the one lockwasher
around
the
connectors.
(2)
Remove
the six
knobs by removing
AGO 3134'
7l