Motorola Pr400 Detailed 6881096c25 B Manual

MOTOROLA and The Stylized M logo are trademarks of Motorola, Inc.
All other product or service names are the property of their respective owners.
© 2005 Motorola, Inc. All rights reserved. Printed in U.S.A.*6881096C25*6881096C25-B
PR400
™
Commercial SeriesPortable Radio 
Detailed Service Manual 

PR400 Portable Radio
Detailed Service Manual
VHF 136-162 MHz
VHF 146-174 MHz
UHF 403-440 MHz
UHF 438-470 MHz
UHF 465-495 MHz
Motorola, Inc.
1301 E. Algonquin Road
Schaumburg, IL 60196
6881096C25-B 

ii
Foreword
This manual is intended for use by service technicians familiar with portable two-way radios. It contains 
service information required for the equipment described and is current as of the printing date. Changes which 
occur after the printing date may be incorporated by a complete Manual revision or alternatively as additions
Product Safety and RF Exposure Compliance  
AT T E N T I O N !
This radio is restricted to occupational use only to satisfy FCC RF energy exposure requirements. 
Before...

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6881096C25-BJune, 2005
Table of Contents
Foreword ..................................................................................................................................................... ii
Computer Software Copyrights ................................................................................................................... ii
Document Copyrights...

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Module 1: VHF 136-162, 146-174 MHz
Chapter 4 136-162 MHz VHF Theory Of Operation ............................ 4-1
4.1 Introduction .................................................................................................................................... 4-1
4.2 VHF Receiver................................................................................................................................. 4-1
4.2.1 Receiver Front-End...

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6881096C25-BJune, 2005
Chapter 7 VHF 136-162 MHz (8486769Z02-A) Schematic Diagrams,
Overlays, and Parts Lists ................................................... 7-5
Figure 7-3. VHF (136-162 MHz) Radio Circuit Block Interconnect Diagram (8486769Z02-A) ........... 7-5
Figure 7-4. VHF (136-162 MHz) Receiver Front End Schematic Diagram (8486769Z02-A).............. 7-6
Figure 7-5. VHF (136-162 MHz) Receiver Back End Schematic Diagram (8486769Z02-A) .............. 7-7
Figure 7-6. VHF...

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Figure 7-35. VHF (146-174 MHz) Voltage Controlled Oscillator Schematic 
Diagram (8486342Z13-C)............................................................................................... 7-45
Figure 7-36. VHF (146-174 MHz) Transmitter and Power Control Schematic 
Diagram (8486342Z13-C)............................................................................................... 7-46
Figure 7-37. VHF (146-174 MHz) Controller Interconnect Schematic Diagram...

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6881096C25-BJune, 2005
8.4 UHF Frequency Generation Circuitry ............................................................................................ 8-4
8.4.1 Fractional-N Synthesizer ..................................................................................................8-5
8.4.2 Voltage Controlled Oscillator (VCO) ................................................................................. 8-6
8.5...

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Chapter 12 UHF 403-440 MHz (8486635Z03-O) Schematic Diagrams,
Overlays, and Parts Lists ................................................. 12-5
Figure 12-3. UHF (403-440 MHz) Radio Circuit Block Diagram (8486635Z03-O).............................. 12-5
Figure 12-4. UHF (403-440 MHz) Receiver Front End Schematic Diagram (8486635Z03-O) ........... 12-6
Figure 12-5. UHF (403-440 MHz) Receiver Back End Schematic Diagram (8486635Z03-O)............ 12-7
Figure 12-6....