Hitachi V-211 - Page 12

3.
PREVENTIVE
MAINTENENCE
Preventive
maintenance,
when performed
on a
regular
basis,
can
prevent
instrument
breakdown and may
improve
the reliability
of
the oscilloscope.
The
severity
of
environment to
which
this instrument
is
subjected
will
determine
the frequency of
maintenance.
A
convenient
time
to
perform
preventive maintenance
is
just
prior
to
the
recalibration of
the instrument.
Disassembly
Remove
all
of
the
screws
on the
top cover
of the instrument, then gently
remove the
top
cover.
Take the
same
procedure
for
the
bottom cover.
Most
of
the internal parts
of
the instrument
are now’
accessible.
(See
section
10.
Exploded view)
Cleaning
The instrument
should
be cleaned
as
often as the operating
conditions
require,
since the
accumulation
of
dirt in the
instrument
may cause
the
component
breakdown.
The
covers
can
provide
protection
against
dust in
the
interior
of
the
instrument.
Loose
dust
accumulated
on
these
covers can be
removed
wTth
a soft
cloth or
small
brush.
Dirt
that
remains
can
be removed
w
?
ith
a soft
cloth
applying in
a
mild
de-
tergent
and w’ater
solution.
Abrasive
cleaners
should not be
used.
Cleaning
the interior
should
be
only
occasionally
necessary. The
best
way
to
clean
the
interior
is
to blow
off the
dust
with
a
dry,
low-velocity
stream
of air.
A
soft-bristle
brush
or a
cotton-tipped
applicator
is
useful
for
cleaning
narrow
7
spaces
or for cleaning
more
delicate
com-
ponents
.
Visual
inspection
The
instrument
should be
inspected
occasionally
for such
defects as
broken
connections,
improperly
seated
transistors, damaged circuit
boards,
and
heat-damaged
parts.
The
corrective procedure
for most
visible
defects
is
apparent;
however,
particular care
must be taken
if
heat-damaged
components
are
found.
Overheating
usually
indicates
7