Motorola GP series Service Manual

iii
Table of Contents
Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS
1.0 GP320/GP340/GP360/GP380 Model Chart.........................................................1-1
2.0 GP140 Model Chart .............................................................................................1-2
3.0 GP640/GP680 Model Chart .................................................................................1-2
4.0 GP1280 Model Chart ...........................................................................................1-3
5.0 GP240/GP280/GP540/GP580 Model Chart.........................................................1-4
6.0 Technical Specifications ......................................................................................1-5
Chapter 2 THEORY OF OPERATION
1.0 Introduction ..........................................................................................................2-1
2.0 UHF Transmitter ..................................................................................................2-1
2.1 Power Amplifier ..............................................................................................2-1
2.2 Antenna Switch...............................................................................................2-2
2.3 Harmonic Filter ...............................................................................................2-2
2.4 Antenna Matching Network ............................................................................2-2
2.5 Power Control Integrated Circuit (PCIC) ........................................................2-2
3.0 UHF Receiver (All models except those with PCB 8486458Z03) ........................2-3
3.1 Receiver Front-End ........................................................................................2-3
3.2 Receiver Back-End.........................................................................................2-4
3.3 Automatic Gain Control (AGC) .......................................................................2-5
4.0 UHF Receiver (Models with PCB 8486458Z03) ..................................................2-6
4.1 Receiver Front-End ........................................................................................2-6
4.2 Receiver Back-End.........................................................................................2-7
5.0 Frequency Generation Circuit ..............................................................................2-8
5.1 Synthesizer.....................................................................................................2-9
5.2 Voltage Controlled Oscillator (VCO).............................................................2-10
6.0 Voice Storage (GP1280 Only) ...........................................................................2-12
Chapter 3 TROUBLESHOOTING CHARTS
1.0 Troubleshooting Flow Chart for Receiver (All models except those with PCB
8486458Z03) (Sheet 1 of 2).................................................................................3-1
2.0 Troubleshooting Flow Chart for Receiver (All models except those with PCB
8486458Z03)(Sheet 2 of 2)..................................................................................3-2
3.0 Troubleshooting Flow Chart for Receiver (Models with PCB 8486458Z03)
(Sheet 1 of 2) .......................................................................................................3-3
4.0 Troubleshooting Flow Chart for Receiver (Models with PCB 8486458Z03)
(Sheet 2 of 2) .......................................................................................................3-4
5.0 Troubleshooting Flow Chart for Transmitter ........................................................3-5
6.0 Troubleshooting Flow Chart for Synthesizer........................................................3-6
7.0 Troubleshooting Flow Chart for VCO...................................................................3-7
8.0 Troubleshooting Flow Chart for Receive Message/Personal Memo Recording ..3-8
9.0 Troubleshooting Flow Chart for Message Playback ............................................3-9

Motorola GP series Specifications

General

Operating Temperature	-30°C to +60°C
Frequency Range	136-174 MHz
Number of Channels	16
Channel Spacing	12.5 kHz / 25 kHz
Battery Life	8 hours (with standard battery)
Operating Voltage	7.5V DC
Ingress Protection	IP54
MIL-STD	810 C, D, E, F