a. Equipment setup is shown in Fig. 6-4.
b. Turn the POWER switch to ON position, then connect
a calibrated voltmeter between pin K on the Vertical Ampli-
fier ond Blanking circuit board, and chassis ground (see Fig.
6-5).
c. If the voltage is not within tolerance, adjust the -10
Volts adjustment R968, for a meter reading of -10 volts.
2. Check +10 Volt and + 150 Volt Power
Supplies
NOTE
The high voltage supply must be operating before
the + 150 volt supply will regulate. If the high
voltage supply is not operating, a substitution
may be made by connecting a 30 volt battery
between the + 150 volt supply and the high volt-
age 175 V supply as follows:
C o n n e c t t h e + l e a d o f t h e b a t t e r y t o p i n A Q
o n t h e p o w e r s u p p l y b o a r d . C o n n e c t t h e - l e a d
of the battery to pin Al.
a. Equipment setup is given in step 1.
b. Connect the voltmeter between pin L of the Vertical
Amplifier and Blanking circuit board and chassis ground
[see Fig. 6-5). Check the +10 volt supply. Must read
b9.7 and +10.3 volts (10 V ±3%).
c. Connect the voltmeter between pin M, of the Vertical
Amplifier and Blanking circuit board, and ground. Check
the +150 volt supply. Must read b145.5 and
+154.4 volts (+150V ±3%).
3 . A d j u s t H i g h V o l t a g e P o w e r S u p p l y
0
a. Test equipment setup is given in step 2.
b. Turn the POWER switch to OFF position. Remove the
CRT base socket, then remove the plastic CRT base socket
cover. Replace the base socket on the CRT.
Fig. 6-5. Location of the low voltage check points.
Fig. 6-6. Adjusting the — 3670 V supply.
6-9
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 ...