Tektronix 067-0521-00, Instruction Manual

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SECTION
2
OPERATING INSTRUCTIONS
Introduction
This information should be used in conjunction with the
calibration procedure section of the oscilloscope instruction
manual.
If desired, any of the following adjustments or
checks may be performed without regard to sequence.
NOTE
If the — 150 Volts control in the oscilloscope is
adjusted, the oscilloscope should be completely
recalibrated.
The 067-0521-00 is calibrated and ready for use as shipped
from the factory.
Power-Supply Output Voltages
To check the oscilloscope power-supply voltages, proceed
as follows:
1. A pply design-center line voltage to the oscilloscope and
turn on the oscilloscope Power switch.
2. Set the 067-0521-00 TEST FUNCTION switch to LOW
LOAD.
3. Measure the voltages at the power-supply test points as
described in the oscilloscope instruction manual.
Power Supply Regulations and Ripple
To check the oscilloscope low-voltage power supply reg­
ulation and ripple, proceed as follows:
1. Set the oscilloscope Amplitude Calibrator switch to O ff
and set the oscilloscope triggering so the time-base cir-
cuit(s) does not free run.
2. W ith the TEST FUNCTION switch set to LOW LOAD,
measure the ripple (with a test oscilloscope) of the various
supplies with the line voltage at 126.5 volts (or 253 volts
if the oscilloscope is wired for 230-volt operation).
3. Set the line voltage at 103.5 volts (or 207 volts) and set
the TEST FUNCTION switch to HIGH LOAD. Measure
the ripple of the various supplies. Refer to the oscillo­
scope instruction manual for ripple voltage limits.
Oscilloscope
Vertical Gain
To check or set the oscilloscope vertical gain, proceed
as follows:
1. Set the TEST FUNCTION switch to the G AIN SET posi­
tion.
2. A pply a 100-volt peak-to-peak Calibrator signal to the
067-0521-00 EXT INPUT connector.
3. Free-run the oscilloscope time base at about 1 msec/cm.
Two traces should be visible on the crt. Use the VERTICAL
POSITION control to center the display.
4. Adjust the oscilloscope Vertical Gain control for exactly
4 cm vertical distance between the two traces. Keep
the display centered vertically on the crt while making
this adjustment.
5. Turn off the Calibrator and disconnect the signal lead.
Oscilloscope Vertical A m p lifie r
Balance
The amount of vertical am plifier dc unbalance must be
small for optimum common-mode rejection ratio and for
linear amplifier operation. To check the amount of dc un­
balance, a suggested procedure is as follows:
1. Set the TEST FUNCTION switch to C O M M O N MODE.
2. W ith a small screwdriver, short the crt vertical deflection-
plate pins together.
CAUTION
Do not short the crt deflection-plate pins to
ground. Excessive current will damage the power
supply.
3. Note the position of the trace. This is the electrical
center of the crt vertical deflection plates.
4. Remove the screwdriver from the crt pins.
5. Note the amount of vertical distance that the trace shifts
between the shorted condition and the non-shorted condi­
tion. Refer to the oscilloscope instruction manual for the
vertical unbalance limit.
If your oscilloscope vertical amplifier has a distributed
am plifier section, the +225V front-panel connector on the
067-0521-00 supplies +2 2 5 volts when the pushbutton switch
is pressed. A lead connected from this connector can be
used to apply + 225 volts to the cathodes of the tubes in
the vertical amplifier. This voltage effectively cuts the tubes
off for checking the dc balance of each stage.
Oscilloscope Alternate-Trace Sync Pulse Check
Set the TEST FUNCTION switch to ALTERNATE. If two
traces appear on the crt, the oscilloscope time-base gen­
erator is producing proper alternate-trace sync pulses for
the plug-in unit. Check each sweep rate to be sure the
sync pulse is present with sufficient amplitude. If the oscillo­
scope has two time bases, make the same check for the
other time base.
Alternate-Sweep Slaving Check
If your oscilloscope is capable of alternating between two
time bases, check this mode of operation as follows:
1. Set the oscilloscope Horizontal Display switch to A lter­
nate.
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