Motorola IC-T81A, IC-T81E service manual

SERVICE

MANUAL

MULTIBAND FM TRANSCEIVER

Contents

Main INTRODUCTION DANGER ORDERING PARTS REPAIR NOTES TABLE OF CONTENTS MGENERAL MTRANSMITTER SECTION 1 SPECIFICATIONS MRECEIVER SECTION 2 INSIDE VIEWS ( ) SECTION 3 DISASSEMBLY INSTRUCTIONS SECTION 4 CIRCUIT DESCRIPTION 4-1 RECEIVER CIRCUITS 4-1-1 DUPLEXER CIRCUIT (RF UNIT) 4-1-2 ANTENNASWITCHING CIRCUITS (RF UNIT) 4-1-3 50 MHz BAND RF CIRCUIT (RF UNIT) 4-1-5 440 MHz BAND RF CIRCUIT (RF UNIT) 4-1-6 1200 MHz BAND RF CIRCUIT (RF UNIT) 4-1-7 1ST MIXER CIRCUIT (RF UNIT) 4-1-8 2ND IF AND DEMODULATOR CIRCUITS (RF AND LOGIC UNITS) 4-1-9 AF AMPLIFIER CIRCUIT (LOGIC UNIT) 4-2 TRANSMITTER CIRCUITS 4-2-1 MICROPHON AMPLIFIER CIRCUIIT (LOGIC UNIT) 4-2-2 MODULATION CIRCUIT (VCO AND RF UNIT) 4-2-3 DRIVE/POWER AMPLIFIER CIRCUITS (RF UNIT) 4-2-4 APC CIRCUITS (RF UNIT) 4-3 PLL CIRCUITS 4-3-1 50 MHz BAND PLL CIRCUIT (RF UNIT) VOLTAGE LINE 4-3-2 144 MHz BAND PLL CIRCUIT 4-3-3 440 MHz BAND PLL CIRCUIT 4-5 PORT ALLOCATIONS 4-5-3 CPU (LOGIC UNIT; IC1) - SECTION 5 ADJUSTMENT PROCEDURES + CAUTION: 5-1 PREPARATION 5-2 PLL ADJUSTMENT Page 5-3 RECEIVER ADJUSTMENT Page Page RECEIVER ADJUSTMENT (Continued) LOGIC UNIT TOP VIEW R733 5-4 TRANSMITTER ADJUSTMENT LOGIC UNIT TOP VIEW R322 R338 R325 TRANSMITTER ADJUSTMENT (Continued) SECTION 6 PARTS LIST 6 - 1 6 - 2 6 - 3 6 - 4 6 - 5 6 - 6 6 - 7 6 - 8 [VCO BOARD] 6 - 9 6 - 10 [VCO BOARD] [VCO BOARD] 7 - 1 SECTION 7 MECHANICAL PARTS AND DISASSEMBLY EP3 [ACCESSORIES] [VCO UNIT] [CHASSIS PARTS] LOGIC unit VCO unit RF unit SECTION 8 SEMI-CONDUCTOR INFORMATION 8 - 1 9 - 1 SECTION 9 BOARD LAYOUTS L702 R733 9-1 LOGIC UNIT DS1 S1 J4 9-2 RF UNIT 9 - 3 C961 40 21 DC-DC MP1 C842 C815 IC802 C86 9-3 VCO BOARD 9 - 6 VCO BOARD BUS TX COMMON RX SECTION 10 BLOCK DIAGRAM 10 - 1 Page VCO BOARD BUS 10 - 1 TX SECTION 10 BLOCK DIAGRAM Q307 Q304 IC201 TA7368F XP4315 SECTION 11 VOLTAGE DIAGRAM 11-1 LOGIC UNIT 4 3 11 - 1 COMPLETE VIEW A 64 Q XC6371A500PR B SECTION 11 VOLTAGE DIAGRAM 11-1 LOGIC UNIT 11 - 1 Q322 Q311 VCO BOARD RF UNIT 11-2 RF UNIT CHG + - 50MHz 3SK292 1200MHz 3SK291 SC5195 VCO BOARD RF UNIT 11-2 RF UNIT INTRODUCTION DANGER ORDERING PARTS REPAIR NOTES