Motorola CM140 Service Information (Page 4 of 68)

Table of Contents

8.3 Dual Tone Multiple Frequency (DTMF) Data ............................................... 2-18

9.0 Receive Audio Circuits....................................................................................... 2-19

9.1 Squelch Detect ............................................................................................. 2-19

9.2 Audio Processing and Digital Volume Control.............................................. 2-20

9.3 Audio Amplification Speaker (+) Speaker (-) ................................................ 2-20

9.4 Handset Audio.............................................................................................. 2-21

9.5 Filtered Audio and Flat Audio ....................................................................... 2-21

10.0 Receive Signalling Circuits ................................................................................ 2-21

10.2 Alert Tone Circuits........................................................................................ 2-22

Chapter 3

3.0 Troubleshooting Flow Chart for Synthesizer........................................................ 3-7

4.0 Troubleshooting Flow Chart for VCO................................................................... 3-8

Chapter 4

VHF1 PCB/ SCHEMATICS/ PARTS LISTS

1.0 Allocation of Schematics and Circuit Boards ....................................................... 4-1

1.1 VHF1 and Controller Circuits.......................................................................... 4-1

2.0 VHF 1-25W Band 1 PCB 8486672Z01 / Schematics .......................................... 4-3

2.1 VHF1 PCB 8486672Z01 Parts List 1-25W ................................................... 4-19

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Motorola CM140 Service Information page 4