Tektronix 184, Инструкция по эксплуатации

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SECTION
4
MAINTENANCE
PREVENTIVE MAINTENANCE
Preventive maintenance consists o·f cleaning, visual
inspection, lubrication, and if needed, recalibration. Pre­
ventive maintenance is generally more economical than
corrective mai ntenance, since preventive maintenance can
usually be done during idle periods at a time convenient
to the user. The preventive maintenance schedule estab­
lished for the instrument should be based on the amount
of use and the environment in which the instrument is used.
Cleaning.
Clean the instrument often enough to prevent
accu mulation of dirt. Dirt on the components acts as a
thermal insulating blanket (preventing efficient heat dis­
sipation) and may provide electrical conducting paths.
Clean the instrument by loosening the accumulated dust
with a dry, soft paint brush. Remove the loosened dust by
vacuum and/or dry, low-pressure compressed air (h igh­
velocity air can damage certain components). Hardened
dirt and grease may be removed with a cotton-tipped swab
or a soft cloth dampened with water and a mild detergent
solution (such as Kelite or Spray White). Abrasive cleaners
should not be used.
CAUTION
Do not permit water to get inside controls or shaft
bushings.
Lubrication.
The life of potentiometers and selector
switches is lengthened if these devices are kept properly
lu bricated. Use a cleaning type lubricant (such as Cramo­
line) on shaft bushings and switch contacts. Lubricate the
switch detents with a heavier grease (Beacon grease No.
325 or equivalent). Do not over-lubricate. The necessary
materials and instructions for proper lu brication of Tek­
tronix instruments are contained in a component lubrica­
tion kit which may be ordered from Tektronix. Order Tek­
tronix Part No. 003-0342-00.
Visual inspection.
After cleaning, the instrument should
be carefully inspected for such defects as poor connections,
damaged parts, and improperly seated transistors. The
remedy for most visible defects is obvious; however, if heat­
damaged parts are discovered, determ ine the cause of
over-heating before the damaged parts are replaced. Other­
wise, the damage may be repeated.
Tube and Transistor Checks
Period ic preventive maintenance checks on the tubes and
transistors used in the instrument are not recommended.
The circuits with in the instrument generally provide the most
satisfactory means of checking tube or transistor usabil ity.
Performance of the circuits is thoroughly checked during
recalibration, so substandard tubes and transistors will
usual ly be detected at that time.
Recalibration
To insure accurate measurements, the instrument cali bra-
®
tion should be checked after each 500 hours of operation,
or every six months if used intermittently.
The calibration procedure can be helpful in isolating
major troubles in the instrument. Moreover, minor troubles
not apparent during regular operation may be revealed
and corrected during calibration.
CORRECTIVE MAINTENANCE
Corrective maintenance consists of component replace­
ment and instrument repair. Special techniques or pro­
cedures required to replace components in this instrument
are described here.
Component identification.
The circuit number of each
electrical part is shown on the circuit diagrams. Note that
a functional group of circuits (such as the power supply)
is assigned a particular series of numbers. Switch wafers
are identified by counting from the first wafer behind the
detent section of the switch towards the last wafer. The
letters F and R indicate whether the front or rear of the
wafer is used to perform the particu lar switching function.
For example, the designation 2R printed by a switch sec­
tion on a schematic identifies the switch section as being
on the rear side of the second wafer when cou nting back
from the detent section.
Parts replacement.
Most of the electronic components
in the Type 184 are standard items available local ly. The
remainder of the electronic components and most of the
mechanical parts are manufactured or selected by Tektronix
to satisfy particular requirements, or are manufactured
for Tektronix to our specifications. However, all parts are
obtainable through your Tektronix Field Engineer or Field
Office. Before purchasing or ordering, consult the Elec­
trical Parts List to determine the value, tolerance, and rat­
ings req uired. See Parts Ordering Information and Special
Notes and Symbols immediately preceding Section 7.
NOTE
When selecting the replacement parts, remember
that the physical size and shape of a component
may affect its performance in the circuit. Parts
orien tation and lead dress should duplicate th ose
of the origina l part, since many of the com po­
n ents are mounted in a particular way to reduce
or control stray capacitance and inductance. Af­
ter repair, portions of the instrument may require
recalibration .
Replacing components o n etched-wiring boards.
Use
ordinary electronic grade 60/40 solder and a 35- to 40-watt
pencil soldering iron with a lis-inch wide chisel tip. The tip
of the iron should be clean and properly tinned for best
heat transfer in a short time to the soldered connection.
A higher wattage soldering iron, if used and applied for
too long a time, ruins the bond between the etched wir­
ing and base material by charring the glass epoxy
lami nate.
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