Adjust Sweep Length - Tektronix 491 Maintenance Manual

Fig. 6-14. Equipment setup to check and adjust sweep circuits, Steps 12 through 20.
Type 491
I N T E N S I T Y
FOCUS and ASTIGMATISM
I N T E N S I F I E R
SCALE ILLUM
POSITION (Horizontal and
Vertical)
T I M E / D I V
VARIABLE
T R I G G E R
SLOPE
LEVEL
S O U R C E
D I S P E R S I O N R A N G E
D I S P E R S I O N - C O U P L E D
R E S O L U T I O N
D I S P E R S I O N B A L
I F A T T E N U A T O R d B
IF CENTER FREQ
VIDEO FILTER
VERTICAL DISPLAY
G A I N
P O W E R
Display of nominal
brightness
Adjusted for optimum
display definition
O F F
As desired
Adjusted for a
horizontally centered
sweep on the graticule
baseline
2 ms
CAL
+
FREE RUN
I N T
M H z / D I V
5 MHz/div
Centered
All switches in off
position
Midrange (000)
O F F
L I N
Midrange
O N
MIXER PEAKING
F I N E R F C E N T E R F R E Q
PHASE LOCK Controls
INT REF FREQ
Test Oscilloscope
Time/Cm
Volts/Cm
Input Coupling
Trigger

12. Adjust Sweep Length

a. Equiment setup is given in Fig. 6-14,
b. Connect the probe from the test oscilloscope to pin S
of the Horizontal Amplifier circuit board.
c. Adjust the Sweep Length R759 (see Fig. 6-15) for a 7.5 V
peak to peak sawtooth waveform on the test oscilloscope
13. Adjust Sweep Calibration and Sweep
Gain
a. Equipment setup is given in step 12.
b. Apply 0.1 ms markers from the Time-Marker Generator
to pin H of the Vertical Amplifier circuit board. Set the Type
491 TIME/DIV selector to .1 ms. Adjust the LEVEL control for
a triggered display.
SEARCH
Centered
OFF
1
ms
2
DC
lnt.-Triggered display
o
o
6-17