Hewlett-Packard
Hewlett-Packard
Hewlett-Packard
Hewlett-Packard
Hewlett-Packard
MX292B Wave-guide to coaxial adapter.
MP 292B Wave-guide to coaxial adapter.
NK292A Wave-guide to coaxial adapter.
11503A flexible wave-guide.
11504A flexible wave-guide,
P E R F O R M A N C E C H E C K P R O C E D U R E
General
In the following procedure, test equipment connections or
control settings should not be changed except as noted. If
only a partial check is desired, refer to the preceding step(s)
for setup information.
The following procedure uses the equipment listed under
Recommended Equipment. If substitute equipment is used,
control settings or setup must be altered to the require-
ments of the equipment used.
Several checks use a 200 MHz signal applied to the RF
INPUT connector. This IF feedthrough signal is not tunable
with the RF center frequency. To avoid interference from
other signals it is recommended that the tunable signals be
positioned off the screen with the RF CENTER FREQUENCY
control.
Preliminary Procedure
Connect the instrument to a power source within the reg-
ulating range of the Type 491. Turn the POWER switch to
ON and allow at least 20 minutes warm up time at 25° C
±5° C before checking the instrument to given accuracy.
Set the front panel controls as follows:
I N T E N S I T Y
FOCUS and
A S T I G M A T I S M
P O S I T I O N
T I M E / D I V
VARIABLE
SLOPE
LEVEL
SOURCE
Dispersion Controls
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
IF CENTER FREQ Controls
I F C E N T E R F R E Q
F I N E
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
Nominal brightness
A d j u s t e d f o r a s h a r p l y
focused display
Position the trace to the
bottom graticule line and
center horizontally
1 ms
CAL
+
F R E E R U N
I N T
M H z / D I V
10 (MHz/div)
All switches OFF
Midrange (000)
Midrange
O F F
L I N
RF Band Selector
F I N E R F C E N T E R F R E Q
M I X E R P E A K I N G
Phase Lock Controls
I N T R E F F R E Q
A
Centered (5 turns from
either extreme)
Search
O F F
1. Trace Alignment
a. Requirement—Horizontal trace alignment is not criti-
cal and is usually set to the operator’s requirement, If mis-
alignment is excessive (approximately 2°) refer to the Cali-
bration Section.
2. Astigmatism
a. Requirement—Well defined display with equally fo-
cused vertical and horizontal segments in the display.
b. Adjust the GAIN control for a display with approxi-
mately 1 division of noise.
c. Adjust the FOCUS control for optimum focus, then
adjust the ASTIGMATISM control for optimum vertical def-
inition. Display should be well defined with optimum setting
of the FOCUS control.
3. Scale Illumination
a. Requirement-Graticule scale illumination must vary
smoothly from no illumination with the SCALE ILLUM control
fully counterclockwise to maximum illumination with the con-
trol fully clockwise.
b. Rotate the SCALE ILLUM control from a fully counter-
clockwise position to full clockwise.
c. Illumination must increase smoothly as the control is
rotated,
4. Position Controls
a. Requirement—Vertical
P O S I T I O N c o n t r o l m u s t p o s i -
tion the sweep beyond the upper and lower graticule limits,
Horizontal POSITION control must position either end of the
sweep into the graticule area.
b. Rotate the Vertical POSITION control to both extremes.
Note that the range of the control equals or exceeds the
requirements in step a.
c. Rotate the Horizontal POSITION control to both ex-
tremes. Note that the range of the control equals or exceeds
the above requirements.
5. Check Sweep Length
a. Requirement—Sweep Length must equal 10.5 divisions
± 0 . 2 d i v i s i o n s .
b. Check the above requirements for the sweep length.
5 - 2
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 ...