Type 491
POWER
ON
M I X E R PEAKING
SEARCH
INTENSITY
Display of nominal
FINE RF CENTER FREQ
Centered
brightness
PHASE LOCK Controls
Adjusted for optimum
F O C U S and ASTIGMATISM
INT REF FREQ
ON
display definition
Test Oscilloscope
INTENSIFIER
OFF
SCALE ILLUM
As desired
Time/Cm
1 ms
P O S I T I O N (Horizontal
Adjusted for a
.2
Volts/Cm
horizontally centered
and Vertical)
Input Coupling
DC
sweep on the graticule
Adjust for free running
Trigger
baseline
sweep
TIME/DIV
2 ms
VARIABLE
CAL
o
9 . Adjust Trigger Level Centering
TRIGGER
a. Equipment setup is shown in Fig. 6-11.
+
SLOPE
FREE RUN
LEVEL
b. Apply the output signal of the Audio Signal Generator
to pin H of the Vertical Amplifier circuit board. Set the Audio
INT
SOURCE
Signal Generator frequency to 20 kHz.
DISPERSION RANGE
MHz/DIV
c. Adjust the Trigger LEVEL control for a voltmeter read-
DISPERSION-COUPLED
5 MHz/DIV
ing of 0 volts between pin C (see Fig. 6-12) of the Hori-
RESOLUTION
zontal Display board and chassis ground.
IF ATTENUATOR dB
All switches in off position
d. Adjust the output of the Audio Generator for 0.2 divi-
I F CENTER FREQ
Midrange (000)
sion (1 minor division) display amplitude on the Type 491.
V I D E O FILTER
OFF
LIN
VERTICAL DISPLAY
e. Adjust the Trig Lev Center R724, for stable sweep
triggering on both + and - SLOPE switch positions.
GAIN
Midrange
