Operating instructions
Maintenance-71380
2
.
When
the
solder begins to
melt,
gently
pull
the
lead
out
.
If
unable
to
pull
out the
lead
without
using
force,
try
re-
moving
the
other
end
of
the
component
as
it
may
be
more
easily
removed
.
NOTE
The
reason
some
component
leads
are
trouble-
some
to
remove
is
due
to
a
bend
placed
on
each
lead
during the
manufacturing
process
.
The
bent
leads
hold
components
in
place
during
a
process
that
solders
many
components
atone
time
.
If
a
component
lead
is
extremely
difficult
to
remove,
it
may
be
helpful
to
straighten
the
leads
on
the
back
side
of
the
board
with
a
small
screwdriver
or
pliers
while
heating
the
soldered
connection
.
Use
only
enough
heat to
remove
the
component
lead
with-
out
removing
the
solder
from
the board
.
If
it is
desired
to
remove
solder
from
a
circuit-board
hole
for
easier
installa-
tion
of
a
new
component,
a
solder-removing
wick
should
be
used
.
3
.
Bend
the
leads
of
the
new
component
to
fit
the
holes
in
the
board
.
If
the
component
is
replaced
while
the
board
is
mounted
in
the
instrument,
cut
the
leads
so
they
will
just
protrude
through
the
board
.
Insert
the
leads
into
the
holes
so
the
component
is
firmly
seated
against
the
board
(or
as
positioned
originally)
.
If
it
does not
seat
properly,
heat
the
solder
and
gently
press
the
component
into
place
.
4
.
Touch
the
iron to
the
connection
and
apply
a
small
amount
of
solder
to
make
a
firm solder
joint
.
To
protect
heat-sensitive
components,
hold
the
lead
between
the
com-
ponent
body
and
the
solder
joint
with
a
pair
of
long-nose
pliers
or
other
heat
sink
.
5
.
Clip
any
excess
lead
protruding
through
the
board
(if
not
clipped
in
step 3)
.
6
.
Clean
the
area
around
the
solder
connection
with
a
flux-
removing
solvent
.
Be
careful
not
to
remove
information
printed
on
the
board
.
COMPONENT
REMOVAL
AND
REPLACEMENT
4-
1
0
WARNING
To
avoid
electrical
shock,
disconnect
the
instru-
ment
from
the
power
source
before
replacing
components
.
The
exploded-view
drawing
associated
with
the
Replaceable
Mechanical
Parts
list
may
be
helpful
in
the
removal
or
dis-
assembly
of
individual
components
or
subassemblies
.
Com-
ponent
locations
and
circuit
board
locations
are
shown
in
the
Diagrams
section
.
Circuit
Boards
If
a
circuit
board
is
damaged
beyond
repair,
replace
the en-
tire
board
assembly
.
Part
numbers
for
completely
wired
boards
are
given
in
the
Replaceable
Electrical
Parts
list
.
A3-READOUT
CIRCUIT
BOARD
.
To
remove
the
circuit
board,
follow
the
procedure
given
in
Figure 4-7
.
A2-TRIGGER
CIRCUIT
BOARD
.
To
remove
the
circuit
board
:
1
.
Remove
3
inter-board
multi-pin
connectors
(see
Figure
4-3 for
identification)
.
2
.
Remove
2
screws
from
circuit
board
.
3
.
Lift rear
of
circuit
board
away
from
frame
and
slide
board
to
the
rear
until
push-button
switches
are
clear
of
the
front panel
.
4
.
Note
wire
color
on
single-conductor
shielded cables
(see
Figure
4-8
for
identification)
and
connector
to
which
each
is
attached
.
5
.
Disconnect
cables
from
back
of
circuit
board
.
To
replace
the
circuit
board,
reverse
the
order
of
removal
.
Al-INTERFACE
CIRCUIT
BOARD
.
To
remove
circuit
board
:
1
.
Remove
Trigger
and
Digital
Voltmeter
circuit
boards
using
procedures
given
previously
.
2
.
Set
TIME/DIV
knob
to
2
ms
position
and
VARIABLE
TIME/DIV
knob
to
expose the
set
screw
.
3
.
With hex-key
wrench,
loosen
set
screws
in
both
knobs
.
Remove
knobs
from
shafts
.
REV
A,
MAY
1978