I N T E N S I T Y
F O C U S a n d A S T I G M A T I S M
I N T E N S I F I E R
SCALE ILLUM
P O S I T I O N ( H o r i z o n t a l
and Vertical)
Fig. 6-11. Equipment setup for adjusting and checking triggering,
Type 491
T I M E / D I V
VARIABLE
TRIGGER
S L O P E
LEVEL
SOURCE
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
I F A T T E N U A T O R d B
I F C E N T E R F R E Q
V I D E O F I L T E R
V E R T I C A L D I S P L A Y
G A I N
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
+
F R E E R U N
I N T
M H z / D I V
5 MHz/DIV
All switches in off position
Midrange (000)
O F F
L I N
M i d r a n g e
P O W E R
O N
M I X E R P E A K I N G
SEARCH
F I N E R F C E N T E R F R E Q
Centered
P H A S E L O C K C o n t r o l s
I N T R E F F R E Q
O N
T e s t O s c i l l o s c o p e
Time/Cm
1 ms
Volts/Cm
.2
Input Coupling
DC
Trigger
Adjust for free running
sweep
9. Adjust Trigger Level Centering
o
a. Equipment setup is shown in Fig. 6-11.
b. Apply the output signal of the Audio Signal Generator
to pin H of the Vertical Amplifier circuit board. Set the Audio
Signal Generator frequency to 20 kHz.
c. Adjust the Trigger LEVEL control for a voltmeter read-
ing of 0 volts between pin C (see Fig. 6-12) of the Hori-
zontal Display board and chassis ground.
d. Adjust the output of the Audio Generator for 0.2 divi-
sion (1 minor division) display amplitude on the Type 491.
e. Adjust the Trig Lev Center R724, for stable sweep
triggering on both + and - SLOPE switch positions.
6 - 1 4
Summary of Contents for 491
Page 4: ...i i Fig 1 1 The Type 491 Spectrum Analyzer ...
Page 24: ...2 16 Fig 2 17 Control set up chart ...
Page 34: ...Fig 3 1 Function block diagram of the Type 491 3 2 ...
Page 42: ...Fig 3 10 Block diagram of the video detector and vertical amplifier 3 1 0 ...
Page 48: ......
Page 53: ...Fig 4 4 Power Supply Circuit board assembly with wiring color code 4 5 ...
Page 54: ...Fig 4 5 Horizontal Display circuit board assembly showing color code to pin connectors 4 6 ...
Page 55: ...Fig 4 6 IF Control board assembly Wiring color code to pin connector 4 7 ...
Page 64: ...Fig 4 20A Tube subassembly removal procedure 4 16 ...
Page 65: ...Fig 4 20B Tube subassembly installation procedure 4 17 ...
Page 68: ...Fig 4 22 Power supply board assembly with component call out 4 2 0 ...
Page 69: ...Fig 4 23 Vertical Amplifier and Blanking board assembly with component call out 4 21 ...
Page 70: ...Fig 4 24 IF control board assembly with component call out 4 22 ...
Page 71: ...Fig 4 24 IF control board assembly with component call out 4 23 ...
Page 72: ...Fig 4 25 Horizontal display board with component call out 4 24 ...
Page 73: ...Fig 4 25 Horizontal display board with component call out 4 25 ...
Page 74: ...Fig 4 26 Phase lock board with component call out 4 26 ...
Page 88: ......
Page 90: ...Fig 6 1 Test equipment recommended for calibration of the Type 491 6 2 ...
Page 138: ......
Page 192: ......
Page 195: ...SECTION II B 3 ...
Page 196: ......
Page 200: ......
Page 201: ...SECTION 9 DIAGRAMS MECHANICAL PARTS LIST ILLUSTRATIONS ACCESSORIES ...
Page 202: ......
Page 203: ...9 1 ...
Page 204: ...9 3 ...
Page 205: ...9 5 ...
Page 206: ...9 7 ...
Page 207: ...9 9 ...
Page 208: ...9 11 ...
Page 209: ...9 13 ...
Page 210: ...9 15 ...
Page 211: ...9 17 ...
Page 212: ...9 19 ...
Page 213: ...9 21 ...
Page 214: ...9 23 ...
Page 215: ...9 25 ...
Page 216: ...9 27 ...
Page 217: ...FIG 1 9 29 ...
Page 218: ...FIG 2 REAR 9 31 ...
Page 219: ...9 33 FIG 3 IF CHASSIS PHASE LOCK ASSEMBLIES ...
Page 220: ...FIG 4 POWER CHASSIS 9 35 ...
Page 221: ...FIG 5 TIME DIV SWITCH OSCILLATOR ASSEMBLIES 9 37 ...
Page 222: ...FIG 6 CRT SHIELD ASSEMBLY 9 39 ...
Page 223: ...FIG 7 CABINET ASSEMBLY HANDLE 9 4 1 ...
Page 224: ...FIG 8 491 STANDARD ACCESSORIES FIG 8 491 STANDARD ACCESSORIES 9 43 ...
Page 225: ......
Page 226: ...PIN 028017 000 ...