APPENDIX B
MAINTENANCE ALLOCATION CHART
Section I.
INTRODUCTION
B-1. General
This Maintenance Allocation Chart designates overall responsibility
for the performance of maintenance functions on the identified end item or
component. The implemeatation of field maintenance tasks upon this end
item
or component will be consistent with the assigned maintenance opera-
tions.
B-2. Maintenance Functions.
Maintenance functions will be limited to and defined as follows:
a. Inspect. To determine serviceability of an item by comparing its
physical, mechanical and electrical characteristics with established standa-
rds.
b. Test. To verify serviceability and to detect electrical or
mechanical failure by use of test equipment.
c. Service. To clean, to preserve, to charge and to add fuel, lubricants,
cooling agents, and air.
If it is desired that elements
ing and lubricating,
, such as paint-
be defined separately, they may be so listed.
d. Adjust.
To rectify to the extent necessary to bring into proper
operating range.
e. Align. To adjust specified variable elements of an item to bring
to optimum performance.
f. Calibrate. To determine the corrections to be made in the readings
of instruments or test equipment used in precise measurement.
Consists of
the comparison of two instruments, one of which is a certified standard of
known accuracy, to detect and adjust any discrepancy in the accuracy of
the instrument being compared with the certified standard.
g. Install.
To set up for use in an operational environment such as
an emplacenment, site, or vehicle.
h. Replace.
To replace unserviceable items with serviceable like items.
i. Repair.
Those maintenance operations necessary to restore an item
to serviceable condition through correction of material damage or a specific
failure. Repair may be accomplished at each category of maintenance.
B-1
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 ...
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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 ...