Tektronix TYPE CA, Инструкция по эксплуатации, Страница: 13 / 36

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MAI NTENANCE
PREVENTIVE MAINTENANCE
Calibration
The Type CA Plug-In Unit is designed for
maximum
stability and should not require fre­
quent recalibration. However, to insure the
accuracy of
measurements, we suggest that you
recalibrate the instrument after
every 500-
hour period
of operation (or every six months
if the unit is used intermittently). A complete
step-by-step procedure for recalibrating the
unit and checking its operation is given in the
Calibration section of this manual. The accuracy
of measurements made with the Type CA Unit
depends not only on the accuracy of the Type
CA Unit calibration but on the associated
oscilloscope calibration as well. Therefore, it
is essential that the oscilloscope be maintained
in
proper calibration.
Visual Inspection
Many potential and existent troubles can be
detected by a visual inspection of the unit,
for this reason, you should perform a com­
plete visual check every time the instrument
is recalibrated or repaired. Apparent defects
may include loose or broken connections, dam­
aged connectors, improperly seated tubes,
scorched or burned parts, or broken terminal
strips, as well as many other troubles. The
remedy for these troubles is readily apparent
except in the case of heat-damaged parts.
Damage of parts due to heat is often the direct
result
of other, less apparent troubles in the
circuit. It is essential that you determine the
cause of overheating before replacing the
damaged parts to prevent damage to the new
components.
COMPONENT REPLACEMENT
The procedures for replacing most parts
in the Type CA Unit are obvious. Detailed
instructions for their removal are therefore
not
required. Other components, however, can
best be removed if a definite procedure is
followed or if certain precautions are taken.
Additional information for the replacement of
some of these parts is contained in the following
paragraphs.
Because of the nature of the
instrument, replacement of certain parts will
require
that you recalibrate portions
of the
instrument to insure proper operation. Refer
to the Calibration section of this manual.
Tubes
Care should be taken both in preventive and
corrective maintenance that tubes are not
replaced unless they are actually causing a
definite circuit malfunction. Many times during
routine maintenance it will be necessary for you
to remove tubes from their sockets. It is
important that these tubes be returned to the
same sockets unless they are actually defective.
Needless replacement or switching of tubes
will many times result in unnecessary
recalibration of the instrument. If tubes do
require replacement, it is recommended that
they be replaced by previously checked high-
quality tubes.
Switches
Methods for removal of defective switches are,
for the most part, obvious and only a normal
amount of care is required. Single
wafers
are normally not replaced on the switches
used in the Type CA Unit, and if one wafer
is defective , the entire switch should be replaced.
Switches may be ordered from Tektronix either
wired or unwired as desired.
Soldering and Ceramic Strips
Many of the components in your Tektronix
instrument are mounted on ceramic terminal
AA
Maintenance - Type CA
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