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Maintenance Manual
MAINTENANCE MANUAL FOR
450-470 MHz, 110 WATT POWER AMPLIFIER
19D902797G3
425-450 MHz, 90 WATT POWER AMPLIFIER
19D902797G7
403-425 MHz, 90 WATT POWER AMPLIFIER
19D902797G6
TABLE OF CONTENTS
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
POWER AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exciter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Small Signal Gain Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Level Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Amplifier Finals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
POWER CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
POWER AMPLFIER READINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IC DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OUTLINE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOW PASS FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DESCRIPTION
The UHF Power Amplifier Assembly is a wide band RF
power amplifier operating over the 403-425, 425-450 and
450-470 MHz range without tuning. Its main function is to
amplify the 10 mW FM signal from the Transmitter Synthe-
sizer to the rated RF output at the antenna port. The output
of the Power Amplifier Assembly is adjustable from rated
power to 3dB lower at the PA output J104.
LBI-38674C
Front Cover
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The assembly consists of a printed wiring board (A1)
and associated components, including a power module and
three RF power transistors, mounted to the heat sink assem-
bly. The printed wiring board (A1) contains both the power
amplifier circuitry and the power control circuitry.
Unfiltered supply voltage, A+, for the power amplifier
circuits enters the assembly via feedthrough capacitor, C1.
Power cable W4 routes the A+ from C1 to J103 on the PWB.
Filtered A+ voltage for the power control circuit enters the
assembly via control cable W13 which connects to the PWB
at J201.
Printed in U.S.A.
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Table of Contents
Related Manuals for Ericsson 19D902797G3
Summary of Contents for Ericsson 19D902797G3
- Page 1 LBI-38674C MAINTENANCE MANUAL FOR 450-470 MHz, 110 WATT POWER AMPLIFIER 19D902797G3 425-450 MHz, 90 WATT POWER AMPLIFIER 19D902797G7 403-425 MHz, 90 WATT POWER AMPLIFIER 19D902797G6 TABLE OF CONTENTS DESCRIPTION ......... . .
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Page 2: Specifications
Power Set line. Four (4) volts on this line will produce to 12 dBm (16 mW). matched to the input of the Combiner. The Combiner is a minimum power. As the voltage increases toward eight (8) Copyright © July 1992, Ericsson GE Mobile Communications Inc. -
Page 3: Theory Of Operation
LBI-38674 volts, the power will increase to its maximum rated output. function of temperature the power is reduced as the tempera- PA Key (Interface Connector pin 2) Fil A+ (Interface Connector pin 6) The PA output power is initially set for an output of 130 watts ture increases. -
Page 4: Troubleshooting Guide
LBI-38674 TROUBLESHOOTING GUIDE (cont’d) UHF POWER AMPLIFIER TYPICAL VOLTAGE READINGS (50 ohm, room temperature, 13.4 Vdc supply voltage, and rated output) SYMPTOM AREAS TO CHECK INDICATIONS Group High Low power at PA output port Low RF input to PA from TX Power should be a minimum Frequency 450 MHZ... -
Page 5: Assembly Diagram
ASSEMBLY DIAGRAM LBI-38674 POWER AMPLIFIER ASSEMBLY 19D902797G3, G6 & G7 (19D902797 Sh.3 Rev.3) - Page 6 ASSEMBLY DIAGRAM LBI-38674 POWER AMPLIFIER ASSEMBLY COVER ASSEMBLY 19D902797G3, G6 & G7 19B801659G3 (19D902797 Sh.2 Rev.6) (19B801659, Sh. 2, Rev. 3)
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Page 7: Parts List
SYMBOL PART NUMBER DESCRIPTION SYMBOL PART NUMBER DESCRIPTION SYMBOL PART NUMBER DESCRIPTION 19D902797G3 Mica/teflon: 33 pF ±2%, 100 VDCW (G3). Metal film: 100 ohms ±5%, 1/8 w. 90 WATT UHF POWER AMPLFIER 19A700006P48 19B801486P101 thru thru 19D902797G6 & G7 Porcelain: 8.2 pF ±5%, 500 VDCW... - Page 8 Receptacle: sim to Amphenol 82-97. PRODUCTION CHANGES 19A702381P408 Tap screw, TORX Drive, M3-0.5 x 8. Part of W1. 19A705106P1 Resistor Spacer. REV. A POWER AMPLIFIER 19D902797G3 J104 7777145P5 Receptacle: sim to Amphenol 82-97. POWER AMPLIFIER BOARD 19D902794G3 COVER — — — MISCELLANEOUS — —...
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Page 9: Assembly Diagram
OUTLINE AND ASSEMBLY DIAGRAMS LBI-38674 COMPONENT SIDE (19D902794, Sh. 2, Rev. 2) LOW PASS FILTER MODULE 19D902856G3 POWER AMPLIFIER BOARD A1 (19D902856 Sh.1 Rev.0) 19D902856G3, G6 & G7... -
Page 10: Schematic Diagram
SCHEMATIC DIAGRAM LBI-38674 POWER AMPLIFIER ASSEMBLY 19D902797G3, G6 & G7 (19D903622 Sh.1 Rev.6) - Page 11 (19D902853, Sh. 2, Rev. 0) (19D903638, Component Side, Rev. 0) SOLDER SIDE (19D902853, Sh. 2, Rev. 0) (19D903638, Solder Side, Rev. 0) POWER AMPLIFIER ASSEMBLY LOW PASS FILTER MODULE 19D902797G3, G6 & G7 19D902856G3 (19D903622 Sh.2 Rev. 6) (19D903623 Sh.1 Rev. 1)
- Page 12 IC DATA LBI-38674 344A3907P1 19A705457P1, P2 AND P4 19A701789P4 MMIC Amplifier PA Amplifier Module Quad Op-Amp U100 19A705532P2 Voltage Regulator...