Tektronix 516 series, Instruction Manual

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M A I N T E N A N C E
Preliminary Instructions
PREVENTIVE MAINTENANCE
Visual Inspection
Every few months, the oscilloscope should be visually in­
spected for possible circuit defects. These defects may include
such things as loose or broken connections, damaged binding
posts, improperly seated tubes, scorched wires or resistors,
missing tube shields, and broken terminal strips. For most
visual troubles the remedy is apparent; however, particular
care must be taken when heat-damaged components are
detected. Overheating of parts is often the result of other,
less apparent, defects in the circuit. It is essential to de­
termine the cause of overheating, before replacing heat-
damaged parts, in order to prevent further damage.
Calibration
The Type 516 Oscilloscope is a stable instrument which
should provide many hours of trouble-free operation. How­
ever, to insure the reliability of measurements we suggest
that you calibrate the instrument after each 500 hours of
operation (or every six months if used intermittently). A
complete step-by-step procedure for calibrating the instru­
ment is presented in Section 6 of this manual.
Air Filter
The Type 516 Oscilloscope is cooled by forced, filtered
air. This instrument is equipped with a washable air filter,
constructed of aluminum wool coated with an adhesive. If
the filter becomes dirty it may restrict the flow of air and
cause the instrument to overheat. The filter should be in­
spected, and cleaned or replaced if necessary, every three
to four months.
To remove the loose dirt, the filter may be rapped gently
on a hard surface. It should then be rinsed briskly, from the
dirty side, with hot water. Or, if preferred, it may be wash­
ed with hot, soapy water. After rinsing and drying, the
filter should then be coated with “ Handi-Coater" or "Filter-
coat", products of the Research Products Corporation. These
products are generally available from air-conditioner sup­
pliers.
Fan Motor
The bearings in the fan motor are sintered bronze oilite
bearings and do not require oiling.
REMOVAL AND REPLACEMENT OF PARTS
General Information
Procedures required for replacement of most parts in the
Type 516 Oscilloscope are obvious. Detailed instructions for
their removal are therefore not required. Other parts, how­
ever, can best be removed if a definite procedure is followed.
Instructions for the removal of some of these parts are con­
tained in the following paragraphs. Parts ordering informa­
tion is included in the Parts List Section.
Because of the nature of the instrument, replacement of
certain parts will require recalibration of sections of the
oscilloscope to insure proper operation.
Removal of Side Panels
The side and bottom panels of the Type 516 Oscilloscope
are held in place by small screwhead fasteners. To remove
the panels, use a screwdriver to rotate the fasteners approx­
imately two turns counterclockwise and pull the panels away
from the instrument (see Fig. 5-1). In replacing the side
panels, be sure that they are fitted properly at the bottom
before fitting the top portion into place. The two side panels
are perforated differently to promote proper air flow within
the instrument. They should not be interchanged. Fig. 2-2
shows the two side panels correctly mounted.
Replacement of the Cathode-Ray Tube
To remove the cathode-ray tube, first disconnect the tube
socket and the five leads connected to the neck of the tube.
Remove the graticule cover, spacer washers, graticule, and
graticule light shield. Loosen the tube clamp at the base of
5-1