Motorola HT Series Service Manual

vi Table of Contents
7.9.4.2 Microcontroller (MCU) .......................................................................... 7-15
7.9.4.3 Low Speed Data Filter.......................................................................... 7-15
7.9.4.4 Keyboard Circuit................................................................................... 7-15
7.9.4.5 BackLight Driver and LED's.................................................................. 7-16
7.9.4.6 Voice Storage....................................................................................... 7-16
7.10 900 MHz Transmitter .................................................................................................. 7-16
7.10.1 Power Amplifier.............................................................................................. 7-17
7.10.2 Antenna Switch.............................................................................................. 7-17
7.10.3 Harmonic Filter .............................................................................................. 7-17
7.10.4 Power Control Integrated Circuit (PCIC)........................................................ 7-17
7.11 900 MHz Receiver ...................................................................................................... 7-18
7.11.1 Receiver Front-End........................................................................................ 7-18
7.11.2 Receiver Back-End........................................................................................ 7-19
7.11.3 Hear Clear IC................................................................................................. 7-19
7.11.3.1 Receive Path for Radios with Hear Clear............................................. 7-20
7.11.3.2 Hear Clear Routing of Data/Signaling .................................................. 7-20
7.11.4 Automatic Gain Control Circuit ...................................................................... 7-20
7.12 Frequency Generation Circuitry.................................................................................. 7-21
7.13 900 MHz Synthesizer.................................................................................................. 7-22
7.14 900 MHz Voltage Control Oscillator (VCO) ................................................................ 7-24
Chapter 8 Maintenance .......................................................................8-1
8.1 Introduction................................................................................................................... 8-1
8.2 Preventive Maintenance ............................................................................................... 8-1
8.3 Inspection ..................................................................................................................... 8-1
8.3.1 Cleaning........................................................................................................... 8-1
8.4 Safe Handling of CMOS and LDMOS........................................................................... 8-2
8.5 General Repair Procedures and Techniques ............................................................... 8-2
8.6 Recommended Test Tools............................................................................................ 8-4
8.7 Replacing the Circuit Board Fuse................................................................................. 8-5
8.8 Removing and Reinstalling the Circuit Board ............................................................... 8-7
8.9 Power Up Self-Test Error Codes .................................................................................. 8-7
8.10 UHF Band 1 Troubleshooting Charts............................................................................ 8-9
8.10.1 Troubleshooting Flow Chart for Controller for all models except
PCB 8486458Z03 ............................................................................................ 8-9
8.10.2 Troubleshooting Flow Chart for Controller for models with
PCB 8486458Z03 .......................................................................................... 8-10
8.10.3 Troubleshooting Flow Chart for Receiver for all models except
PCB 8486458Z03 (Sheet 1 of 2) ................................................................... 8-11
8.10.4 Troubleshooting Flow Chart for Receiver for all models except
PCB 8486458Z03 (Sheet 2 of 2) ................................................................... 8-12
8.10.5 Troubleshooting Flow Chart for Receiver, for models with
PCB 8486458Z03 (Sheet 1 of 2) ................................................................... 8-13
8.10.6 Troubleshooting Flow Chart for Receiver, for models with
PCB 8486458Z03 (Sheet 2 of 2) ................................................................. 8-14
8.10.7 Troubleshooting Flow Chart for Transmitter .................................................. 8-15
8.10.8 Troubleshooting Flow Chart for Synthesizer.................................................. 8-16

Motorola HT Series Specifications

General

Battery Type	Li-Ion
Waterproof	IP54
Operating Temperature	-30°C to +60°C
Frequency Range	VHF: 136-174 MHz
Number of Channels	16