Tektronix 561A, Инструкция по эксплуатации

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Section 2
Operating Instructions
Introduction
Before operating the Type 561A Oscilloscope, be sure
that the instrument will cool properly, the proper line volt­
age is used, and the crt deflection potentials are corre :t.
Cooling
The air must be able to flow freely around the instrument
so that it may cool. Vacuum tubes should not be operat' d
with envelope temperatures above 150° C when the ambient
temperature is at 25° C, or above 175° C when the ambi ­
ent temperature is at 50° C. The Type 561 A can opercte
in ambient temperatures up to 50° C. If the instrument
overheats, the thermal cutout will turn off the power.
used in place of a sweep plug-in unit. However, it will be
necessary to elevate the unconnected crt deflection plates
to about 4-180 to 4-210 volts de, to obtain proper focus
and astigmatism control.
Blank Chassis
Blank-chassis plug-in units are available from your local
Tektronix Field Office as Modification Kit number 040-245.
Blank chassis permit you to build your own plug-in circuitry
for use in the Type 561 A.
Heat Dissipation — Plug-in unit circuitry should not elevate
the instrument temperature above the limits discussed pre­
viously under Cooling.
117-Volt Operation 234-Volt Operation
Operation
Operation of the Tektronix Type 561A Oscilloscope with
two plug-in units in place is much the same as that of a
conventional Tektronix oscilloscope with corresponding verti­
cal and horizontal deflection systems. The plug-in units
take the place of the vertical and horizontal deflection
systems in a conventional oscilloscope; their outputs con ­
nect directly to the deflection plates of the cathode-ray
tube. The plug-in units can be selected to give the Type
561A Oscilloscope the degree and type of performance
demanded of it by a particular application.
The front and back panels of the Type 561A have con ­
trols or switches that affect the display; however, the plug ­
in units determine the major characteristics of the display.
Fig. 2-1. Power transformer primary connections for operation of
Type 561A Oscilloscope at 117 or 234 volts.
Line Voltage
The Type 561 A instrument can be wired for either 117-
volt or 234-volt operation. It will operate properly betwe m
105 and 125 volts when wired for 117-volt operation, and
between 210 and 250 volts when wired for 234-volt opera ­
tion. A small metal tag on the rear of the instrument indi ­
cates the voltage for which it is wired at the factory.
Converting from one operating voltage to another requires
a change in the power transformer primary connections, t re
fuse, and the male line cord plug.
Fig. 2-1 indicates the transformer primary connections
for 117-volt and 234-volt operation. A 2-amp slow-blowi rg
type fuse is required for 117-volt operation, and a 1-ar ip
slow-blowing type fuse is required for 234-volt operatic n.
Deflection Plate Voltages
The Type 561A may be operated with only one plug in
unit if desired. For example, moving film recording may l >e
Front Panel
The POWER ON switch permits turning the instrument on
or off.
The SCALE ILLUM. control permits adjustment of the
brightness of the graticule markings.
The FOCUS control permits proper trace or spot focus
for most intensity values.
The ASTIGMATISM control works in conjunction with the
FOCUS control, and improves the focus over the entire
crt display.
The INTENSITY control permits changing the crt display
brightness.
The ALIGNMENT control permits electronically tilting
the level of the crt trace to agree with the horizontal
graticule markings.
The 18-position CALIBRATOR switch determines the peak-
to-peak amplitude of the signal at the CAL. OUT connector.
It also permits turning the CALIBRATOR off. The calibrator
output is used to set the gain of the amplifier plug-in units
and to check the basic timing of the time-base units.
2-1