Icom IC-T90A manual Table of Contents

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TABLE OF CONTENTS

SECTION	1	SPECIFICATIONS
SECTION	2	INSIDE VIEWS
SECTION	3	DISASSEMBLY INSTRUCTIONS
SECTION	4	CIRCUIT DESCRIPTION
	4 - 1	RECEIVER CIRCUITS	4 - 1
	4 - 2	TRANSMITTER CIRCUITS	4 - 4
	4 - 3	PLL CIRCUITS	4 - 5
	4 - 4	POWER SUPPLY CIRCUITS	4 - 7
	4 - 5	PORT ALLOCATIONS	4 - 7
SECTION	5	ADJUSTMENT PROCEDURES
	5 - 1	PREPARATION	5 - 1
	5 - 2	TRIMMER ADJUSTMENT	5 - 3
	5 - 3	ADJUSTMENT MODE ADJUSTMENTS	5 - 5
SECTION	6	PARTS LIST
SECTION	7	MECHANICAL PARTS AND DISASSEMBLY
SECTION	8	SEMI-CONDUCTOR INFORMATION
SECTION	9	BOARD LAYOUTS
	9 - 1	LOGIC UNIT	9 - 1
	9 - 2	RF UNIT	9 - 3
	9 - 3	AF UNIT / VCO UNIT	9 - 5
SECTION	10	BLOCK DIAGRAM
SECTION	11	VOLTAGE DIAGRAM

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Contents IC-t90a Sample Order IntroductionOrdering Parts Repair NotesTable of Contents Specifications GeneralTransmitter WFM ReceiverFrequency MHz WFMBottom view Inside ViewsLogic Unit Top viewAF Unit RF UnitTop view Bottom view Removing the rear panel Removing the AF unit Disassembly InstructionsReceiver Circuits Circuit Description4 1ST Mixer and 1ST if Circuits RF, AF and VCO Units 5 2ND if and Demodulator Circuits AF UnitRF Circuit AF Amplifier Circuit AF Unit Squelch Circuitaf and Logic Units2ND if and Demodulator Circuit Transmitter Circuits APC Circuit PLL CircuitsAPC Circuit RF Unit GeneralPLL Circuit VCO Divider Circuit VCO and RF UnitsVoltage Line Power Supply Circuits2 R3V Switch IC AF Unit IC51 Port AllocationsCPU Logic Unit IC1 SEG35 CtselDtcs LCDPreparation Adjustment ProceduresOperation on the Adjustment Mode Operation on the Output Power AdjustmentConnection JIGAD-92SMA Voltage Trimmer AdjustmentPLL Lock VCOL19 VCO UnitRF Unit L16 L456Frequency Adjustment Mode AdjustmentsReference DialAdjustment Mode Adjustments PH ch 53.900 MHz Transmitting 8V 145 MHz Displayed frequency Connect an amme 45 a R326 Logic UnitR325 R365Ctcss Detector CoilTracking L151 AF UnitCP0 IC151, pin 12 SD lineDisplayed frequency Connect a DC volt Maximum voltage Meter Adjustment Adjustment Condition OperationOrder Description Section Parts ListCoil Eljre 3N9Z-F Ceramic ECJ0EB1H681K Connector AXK6S30445P Ceramic ECJ0EC1H060C Encoder Trimmer Tantalum ECST1EY474R Ceramic ECJ0EC1H2R5B Mechanical Parts and Disassembly AccessoriesChassis Parts AF Unit VCO Unit Logic UnitRF Unit Chassis PartsName SEMI-CONDUCTOR InformationTransistors and Fets DiodesDUP Board LayoutsTOP View MC1 MicrophoneSQL PTT Logic unitBottom View SP1RF Unit RF unit AF Unit VCO UnitEXT.SP EXT.MICREMOTO S253S252 Logic Unit Block DiagramLoop LPF HPF Drive BPF ANT FIL AMP Chassis11 1 Logic Unit Voltage DiagramIC5 2SK3476 11 2 RF UnitBU4094BCFV 11 3 AF UnitURL 32, Kamiminami, Hirano-ku, Osaka 547-0003, Japan