Tektronix 543B Instruction Manual page 21

PREVENTIVE MAINTENANCE
Panel Removal
The side and bottom panels of the Type 543B are held
in place with coin-slotted fasteners. To remove the panels,'
turn each fastener a quarter turn counterclockwise.
When replacing the panels, position as indicated on the
inside of each panel to insure proper air flow throughout
the instrument.
For instructions on removing the cabinet from the Type
RM543B see Rackmounting Instructions.
Recalibration
To insure accurate measurements, check the calibration
of the instrument after 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 also be helpful in localiz­
ing certain troubles in the instrument. In some cases minor
troubles, not apparent during normal use, may be revealed
and/or corrected by recalibration.
Visual Inspection
The Type 543B should be inspected occasionally for such
defects as broken connections, broken or damaged ceramic
strips, improperly seated tubes or transistors and heat-
damaged parts.
The remedy for most visible defects is obvious; however,
particular care must be taken if heat-damaged parts are
located. Overheating is usually only a symptom of trouble.
For this reason, it is essential to determine the actual cause
of overheating before the heat-damaged parts are replaced;
otherwise, the damage may be repeated.
Cleaning
The Type 543B should be cleaned as often as operating
conditions require. Accumulations of dirt in the instrument
can cause overheating and component breakdown.
on components acts as an insulating blanket and prevents
efficient heat dissipation. It also provides a conduction path
for electricity. Dirt in the air filter chokes the flow of cool­
ing air and results in excessive operating temperature.
Air Filter. The air filter should be visually checked every
few weeks and cleaned if dirty. More frequent inspections
and cleaning arc required under severe operating condi­
tions. To clean the filter, wash it out in the same manner
as a plastic sponge. Rinse the filter thoroughly and let it
dry. Coat the dry filter with fresh "Filter Kofe" (Tektronix
Part Number 006-580) or "Handi-Kcter" (available locally
through most air conditioner suppliers). Let the filter dry
thoroughly before reinstalling.
SECTION 4
MAINTENANCE
Exterior.
Type 543B can be removed with a cloth or small paint
brush. The paint brush is particularly useful for dislodging
dust on and around the front-panel controls. Stubborn dirt
can be removed with a soft cloth dampened in a mild
solution of water and detergent. Abrasive cleaners should
not be used.
Clean the face of the ert with a soft, lint-free cloth
dampened with denatured alcohol,
Avoid the use o f chemicals which might damage
the plastics used in this instrument, particularly
the iucite plastic ert faceplate.
to avoid are benzene, toluene, xylene, acetone
or similar solvents.
Interior.
some dust may penetrate into the interior of the instrument.
This dust should be removed occasionally due to its con­
ductivity under high humidity conditions.
to clean the interior of the equipment is to first carefully
vacuum all accessible areas and then blow away the re­
maining dust with dry, low-pressure air. Avoid the use of
high-velocity air which might damage some of the compo­
nents.
brush or a damp cloth dampened with a mild detergent
and water solution.
for cleaning in narrow 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 special attention.
Excessive dust and dirt in these areas may cause high-
voltage arcing and result in improper instrument operation.
Lubrication
The fan motor bearings should be lubricated every three
or four months with a few drops of light machine oil (see
Fig. 4-1). Failure to lubricate the fan bearings periodically
may cause the fan to slow down and eventually fail.
Dirt
Soldering
Special silver-bearing solder is used to establish a bond
to the ceramic terminal strips in Tektronix instruments. This
bond can be broken by repeated soldering (especially if
ordinary tin-lead 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 543B. Additional silver-bearing solder can usually
be purchased locally; however, it may be purchased through
your Tektronix Field Engineer or representative—specify
part number 251-514.
Loose dust accumulated on the outside of the
CAUTION
Although air entering the Type 543B is filtered,
Remove any dirt which remains with a soft paint
A cotton-tipped applicator is useful
CORRECTIVE MAINTENANCE
Some chemicals
The best way
4-1