Tektronix 543B Instruction Manual page 21

SECTION 4
MAINTENANCE
PREVENTIVE
MAINTENANCE
Panel
Removal
The
side
and boffom
panels of
*he
Type
543B ore held
in
piece with coin-slotted fastenefs.
To remove
Ihc ponels,'
turn
each
fastener
a
quarter
lorri
courjferclockwise.
When
replacing
the panels,
posifiofi
os indicoled
on
the
inside of
each
ponet
to
insure
proper
air
flow throughout
the instrument.
For instructions
orr
removing the cabinet from
the
Type
RM543B
see
Rackmounfing
Instructions.
Recalibration
To
insure
occurote meosuremenfs, check the
calibration
of the instrument offer
each 500
hours of operation or every
six
months
if
used intermittently.
Complete
calibration
in-
structions
are given
in
Section 5 of
this
manual.
The
calibration
procedure can
olso
bo
helpful
in
localiz-
ing certain troubles
in
the instrument.
In
some
coses
minor
troubles, not
opporent during normal
use,
may
be
reveoled
and/or
corrected
by
recalibration.
Visual Inspection
The Type 543B
should be inspected occosionoliy
for
such
defects os broken connections, broken
or
domaged
ceramic
strips,
improperly seated tubes
or tronsistors
ond
heaf-
damoged
ports.
The
remedy
for most
visible defects
is
obvious; however,
particular care must be token
if
heat-damaged
ports
are
located.
Overheating
is
usually only
a symptom
of trouble.
For
this
reason,
it is
essential to
determine the actual
cause
of overheotlng before the
heat-damaged
ports
are repioced;
otherwise, the
damage may
be repeated.
Cleaning
The Type 543B should
be deoned
os often as operating
conditions require.
Accumulotions
of
dirt in
the instrument
can
cause
overheating
ond component breokdown.
Dirt
on
components
acts os
an
insuloting bionket
and prevents
efficient
heat
dissipation.
It
olso provides
o
conduction path
for electricity. Dirt
in
the
air
filter
chokes the flow of cool-
ing air
and
results in
excessive operoting temperolure.
Air
Filter.
The
air
filler
should
be
visuoliy
checked every
few weeks and deoned
if
dirty.
More
frequent inspections
and cleaning
ore
required under severe operoting condi-
lions.
To
dean
the filter,
wash
it
out
in
the
some monner
as
a
plastic
sponge. Rinse the
filter
thoroughly and
lei
it
dry.
Coat
the
dry
filler
with fresh
'Filter
Kote"
(Tektronix
Port
Number
OOb-580) or
"Hondi-Kofer"
(ovoiloble locally
through most
air
conditioner
suppliers).
Let
the
filter
dry
thoroughly betore
remstalling.
Exterior. Loose dust
occumulated on
the outside of the
Type 5438 can be removed
with
a
doth
or small
paint
brush.
The
point brush
is
particularly useful
for
dislodging
dust
on and around
the front-panel
controls.
Stubborn
dirt
can be removed
with a
soft
doth
dampened
in
a mild
solution of
water
and
detergent. Abroslve cleaners should
not be
used.
Clean
the foce of
the ert
with o
soft, lint-free
doth
dampened
with
denatured
alcohol,
CAUTION
Avoid
the
use
of
chemicals which might
damage
the
plastics
used
in this
instrument, particularly
the
lucife plastic ert
faceplate.
Some
chemicols
to
ovoid ore benzene,
toluene, xylene,
ocetone
or similor solvents.
Interior. Although
oir entering the
Type
543B
is
filtered,
some
dust
moy
penetrate
into the interior
of the instrument,
This
dust
should be
removed
occasionally due
to
its
con-
ductivity under high humidity
conditions.
The
best
way
to cleofj
the
interior
of the
equipment
is
to
first
carefully
vacuum
all
occessible
areas
and
then
blow
owoy
the
re-
maining dust with dry, low-pressure
air.
Avoid
the use of
high-velocity air
which
might
damage
some
of the
compo-
nents.
Remove
any
dirt
which
remains with a
soft
point
brush or a
domp
cloth
dampened
with a mild
detergent
ond wafer
solution.
A
cotton-tipped applicator
is
useful
for
cleaning
in
norrow
spaces or
for
cleaning ceramic
terminal strips or
etched wiring boards.
The high-voltage
circuits
including parts located
under
the
high-voltage
shield
should receive speciol attention.
Excessive
dust
ond
dirt in
these
areas
may
cause high-
voltage arcing
and
result in
improper
instrument operation.
Lubrication
The
fon motor bearings should be
lubricated
every three
Of
four
months with a
few
drops
of light
machine
oil
(see
Fig. 4-1).
Failure
to
lubricote the
fan beorings periodically
moy
cause the fan to
slow
down
and
eventually
fail.
CORRECTIVE
MAINTENANCE
Soldering
Speciol silver-bearing solder
is
used
to establish
a
bond
to
the ceromic terminal
strips in
Tektronix instruments. This
bond can bo broken by repeated
soldering (especially
if
ordinory
tin-icod solder
is
used) or
by excessive heating.
Solder containing about
3%
silver
is
recommended.
A
small
supply
of this
solder
is
provided on
a spool
mounted
inside
the
Type
5438. Additionol
silver-bearing solder
can usually
be
purchosed
locoily;
however,
it
may
be purchased
through
your
Tektronix
Field Engineer
or
representative
—
specify
port
number
251-514.
4-1