Icom IC-F21S service manual UHF FM Transceivers

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SERVICE MANUAL

UHF FM TRANSCEIVERS

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Contents UHF FM Transceivers Ordering Parts IntroductionRepair Notes Table of Contents ‘ General Specifications‘ Transmitter ‘ ReceiverMain Unit TOP View Inside ViewsBottom View Removing the Chassis Disassembly InstructionsRemoving the Main Unit Receiver Circuits Circuit DescriptionTransmitter Circuits General PLL CircuitVCO Circuit PLL CircuitPort Allocations Power Supply Circuits Voltage LinePin Port Description Number 3 D/A Convertor IC IC9 Output Expander IC IC15Preparation Adjustment ProceduresJIG cable Screen display exampeSPE GNDDC Power Supply GND DC power cable connectionsConnection PLL Lock PLL AdjustmentMain VoltageSoftware Adjustment Squelch SensitivityLevel SQLUnit Section Parts ListMain Unit Coil Eljfc R68M-F Array Electrolytic ECEV1CA470SP Connector Accessories Mechanical Parts and DisassemblyChassis Parts Screw abbreviations B0, BT Self-tappingIC-F21S Transistor and FET’S SEMI-CONDUCTOR InformationDiodes Main Unit Board LayoutsIC6 FT1TOP View SW-A Unit SW-A and SW-B UnitsSW-B Unit CBI0 CBI1 CBI2 CBI3 Bottom View SW-A UnitGND Tled Rled VCC Volin Volout Disassembly Information Parts ListBC-146 Optional Desktop Charger Information Charge UnitBoard Layout Voltage DiagramSW-A/SW-B Unit S1 Block Diagram2SC4215 O Voltage DiagramDTC144EU Section Voltage Diagram Q1 XP4216 SW-A UnitPage 32, Kamiminami, Hirano-ku, Osaka, 547-0003, Japan