Table of Contents
Advertisement
Table of Contents
Controller................................................................................................................................................................................ 2-5
Functions.......................................................................................................................................................................... 2-5
Normal Operation .......................................................................................................................................................... 2-5
Clock Synthesizer ........................................................................................................................................................... 2-5
Bus Operation.................................................................................................................................................................. 2-5
RAM .................................................................................................................................................................................. 2-5
EEPROM .......................................................................................................................................................................... 2-5
SPI Interface..................................................................................................................................................................... 2-6
LED Control..................................................................................................................................................................... 2-6
Audio & Data Circuitry ................................................................................................................................................. 2-6
External PTT Sense Circuits .......................................................................................................................................... 2-6
MIC Amplifier................................................................................................................................................................. 2-6
TX Data Circuits.............................................................................................................................................................. 2-6
Sub-Audible Data (PL/DPL) ........................................................................................................................................ 2-7
High-Speed Data............................................................................................................................................................. 2-7
DTMF Data ...................................................................................................................................................................... 2-7
MDC Data ........................................................................................................................................................................ 2-7
RX Audio Processing and Digital Volume Control ................................................................................................... 2-7
Audio Power Amplifier ................................................................................................................................................. 2-8
Audio PA Muting and Output Protection .................................................................................................................. 2-8
Receive Data Circuits ..................................................................................................................................................... 2-8
Alert Tone Circuits ......................................................................................................................................................... 2-8
Section 3
Overview................................................................................................................................................................................. 3-1
Description ............................................................................................................................................................................. 3-1
Operation ................................................................................................................................................................................ 3-1
Handling Precautions ........................................................................................................................................................... 3-1
Maintenance ........................................................................................................................................................................... 3-2
Section 4
Overview................................................................................................................................................................................. 4-1
Troubleshooting Charts ........................................................................................................................................................ 4-1
Troubleshooting Flow Chart for Receiver ........................................................................................ 4-2
Troubleshooting Flow Chart for Transmitter.................................................................................... 4-3
Troubleshooting Flow Chart for Synthesizer.................................................................................... 4-4
Troubleshooting Flow Chart for Controller ...................................................................................... 4-5
Section 5
Test Mode/Entry ................................................................................................................................................................... 5-1
Test Mode/Channel Selection ............................................................................................................................................. 5-1
Test Mode/Tx Modulation................................................................................................................................................... 5-2
Exiting Test Mode.................................................................................................................................................................. 5-2
Fail Mode ................................................................................................................................................................................ 5-2
Performance Checks.............................................................................................................................................................. 5-3
Section 6
Introduction............................................................................................................................................................................ 6-1
ii
GTX/GTX LTR /LTS 2000 Portable Radios Service Manual
68P02945C75-A
June 1999
Advertisement
Table of Contents
Troubleshooting
