Tektronix 535A, Instruction Manual

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General
The Type 535A Oscilloscope is a versatile instrument which
is adaptable to a great number of applications. However,
to make use of the full potentialities of the instrument, it is
necessary that you understand completely the operation of
each control. This portion of the Operator's Manual is in­
tended to provide you with the basic information that you
require. If you are familiar with other Tektronix Oscillo­
scopes, you should have very little difficulty in understanding
the operation of the Type 535A since the function of many
controls is the same as the function of corresponding con­
trols on other Tektronix instruments.
Plug-In Units
The Type 535A Oscilloscope is designed to operate with
any one of the Tektronix letter-series plug-in units. The
particular plug-in unit used must be selected by you to sat­
isfy the requirements of your application. In selecting the
plug-in unit for any particular application, you must con­
sider the bandpass, sensitivity, and type of input required
for that application. The plug- in units available will satisfy
the requirements for most applications.
Preparation for Use
When the plug-in unit has been selected, insert it into the
plug-in compartment of the oscilloscope and press firmly to
insure that the connectors make proper contact. Tighten
the plug-in unit locking control to hold the unit securely in
place and turn the oscilloscope INTENSITY control fully
counterclockwise.
Refer to the voltage input marking on the back panel of
the instrument to verify that it is wired for the line voltage
you have available. Refer to the maintenance section of this
manual if you need to change the power transformer and
fan wiring for a different input voltage.
Connect the power cord to the rear of the instrument and
to the power line and place the POWER switch in the ON
position.
Cooling
A fan maintains safe operating temperature by circulating
filtered air over the rectifiers and other components. When in
operation, the instrument must be placed so that the air in­
take at the back is clear of any obstruction that might im­
pede the flow of air. Side panels should also be in place for
proper air circulation. The air filter should be kept clean,
in accordance with cleaning instructions found in the Main­
tenance Section of this manual.
Under no circumstances should your Oscilloscope be op­
erated without the fan running. Without the fan, inside tern-
ON 2
OPERATING
INSTRUCTIONS
perature of the oscilloscope will rise to a dangerous level
in five to ten minutes. In this event, the thermal cutout
switch will disconnect the power and keep it disconnected
until the temperature drops to a safe level.
Time Delay
Time delay relays used in the Type 535A Oscilloscope
delay operation of the instrument for approximately 25 sec­
onds after the POWER switch is turned on to allow a brief
tube-warmup period. The delay allows the tubes sufficient
time to heat before the dc operating voltages are applied.
If the ac power is off for only an instant, the normal 25-
second delay will occur before the instrument returns to full
operation. This delay will occur regardless of whether the
ac power is off because of a momentary power failure or
is turned off with the POWER switch.
Focus and Astigmatism Controls
The FOCUS and ASTIGMATISM controls operate in con­
junction with each other to allow you to obtain a sharp,
clearly defined spot or trace. The proper setting of the
ASTIGMATISM control is obtained by rotating the FOCUS
control fully clockwise, setting the HORIZONTAL DISPLAY
switch to EXT. ×10, and adjusting the INTENSITY control to
obtain a spot on the screen. After positioning the spot to
the center of the screen, the ASTIGMATISM control is ad­
justed for the most nearly circular spot possible. The FOCUS
control is then adjusted to reduce the spot diameter as
much as possible. (You must be certain that all input signals
to the oscilloscope are disconnected when you adjust the
FOCUS and ASTIGMATISM controls.)
Intensity Control
The INTENSITY control is used to adjust the brightness
of the oscilloscope display. This permits you to compen­
sate for changes in brightness resulting from changes in the
sweep or triggering rate. The INTENSITY control is rotated
clockwise to increase brightness and counterclockwise to
decrease brightness. Care must be taken when using the
INTENSITY control that the brightness is not turned up to
the point where the face of the cathode-ray tube is per­
manently damaged. If the intensity of the beam is turned up
too far, the phosphor on the face of the crt may be burned.
The intensity of the beam should never be turned up to
the point where a halo forms around the spot.
Graticule Illumination Control
The graticule used with the Type 535A Oscilloscope is
accurately marked with 10 horizontal and 6 vertical 1-centi­
meter divisions with 2-millimeter markings on the center­
lines. These graticule markings allow you to make time and
voltage measurements from the oscilloscope screen.
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