Tektronix 535A, Инструкция по эксплуатации

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Calibration Procedure—Type 535A
turning the STABILITY control full right. Position the trace
directly behind the center graticule line. If the trace and the
graticule line do not coincide over the width of the graticule,
rotate the crt until they are properly aligned.
After aligning, push the crt forward until it rests snugly
against the graticule, and tighten the crt base clamp. Re­
check the alignment of the trace after tightening the clamp
to be sure the crt didn't rotate while the clamp was be­
ing tightened.
5. CRT Geometry
The geometry of the crt display is adjusted by means of
the GEOMETRY control. To achieve optimum linearity, verti­
cal lines are displayed on the crt and the GEOMETRY con­
trol is adjusted for minimum curvature of the lines. Nonlin­
earity is most noticeable at the edges of the graticule.
Set the front panel controls as follows (use TIME BASE A):
HORIZONTAL DISPLAY A
TRIGGERING MODE AC
TRIGGER SLOPE +INT
TIME/CM .5 MILLISEC
VARIABLE
VOLTS/CM (plug-in)
CALIBRATED (full right)
.2
Connect 500 µsec markers from the Type 180 or 180A to
the INPUT connector and position the base line of the tim­
ing comb below the bottom of the crt face so it is not vis­
ible. Adjust the GEOMETRY control for straight vertical lines
running parallel to the left and right edges of the graticule.
NOTE
The amplitude calibrator may be used for this
step, but due to the low intensity of the vertical
lines, the adjustment is somewhat more dififcult.
6. ‘ A’ Triggering Level
Set the HORIZONTAL DISPLAY switch at A. Place the
A' TRIGGERING MODE switch at DC and the 'A' TRIGGER
SLOPE switch at +INT. Rotate the 'A' TRIGGERING LEVEL
control to zero and the ‘A ’ STABILITY control full left, but
not to the PRESET position. Connect the dc voltmeter from
the junction of R19 and R20 (see Fig. 6-6) to ground. Set
the voltmeter on the lowest voltage range and adjust 'A'
TRIGGERING LEVEL control for a meter reading of exactly
zero volts. If the TRIGGERING LEVEL knob does not read
exactly at the zero position, loosen the set screw and re­
position the knob. The voltmeter should read zero, when
the TRIGGERING LEVEL control is set at zero.
junction of R19 and R20. Set Trig. Sens. (See top View, Fig.
6-3) to center of rotation. Connect jumper from CAL. OUT
Fig. 6-6. Time Base A Triggering Circuit Test Points.
to TRIGGER INPUT, and set CALIBRATOR to 1 VOLT. Use
10× probe with test scope set to .5 VOLTS/CM and TIME/
CM to .5 MILLISEC. Now, connect the probe tip to pin 6 of
V45 and carefully adjust the Trig. Level Centering (see Top
View. Fig. 6-3) control to the exact center of the area which
gives a square-wave of approximately 1% cm on the test
scope. Next, reduce the calibrator output to .2 volts and
slowly turn the Trig. Sens, control to the right until the
square-wave is again observed on the test scope. Carefully
adjust this control to the point where the square-wave is
jitter-free. Very slightly readjust Trig. Level Centering and
Trig. Sens, controls for best response on the test scope. Do
not turn the Trig. Sens, control any farther to the right than
is necessary to provide stable triggering.
8. ‘A ’ Internal Trigger DC Level
Set the 'A' STABILITY control for a free-running sweep, the
TRIGGER SLOPE to —INT. and the TRIGGERING MODE to
DC. Position the trace to the center of the graticule and
connect the dc meter between ground, and the junction of
R22 and SW10A. (See Fig. 6-6). Set the meter on the lowest
voltage range and adjust the Int. Trig. DC Level Adj. (see
Top View, Fig. 6-3) for exactly zero voltage.
9. ‘ A’ Preset Adjust
Place the 'A' TRIGGERING MODE switch at AUTO, and
the TRIGGER SLOPE switch at -(-LINE. Connect the dc volt­
meter between the PRESET ADJUST potentiometer wiper arm
7. ‘ A’ Trigger Level Centering and Trigger Sen­
sitivity
Set TRIGGERING MODE switch at AC, TRIGGER SLOPE
to —EXT., TIME/CM to .5 MILLISEC. Use clip lead to ground
6-5