Icom IC-F21S service manual Inside Views, Main Unit TOP View, Bottom View

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SECTION 2 INSIDE VIEWS

Power amplifier (Q1: 2SK2974)

Pre-drive (Q2 : 2SK2973)

YGR amplifier (Q3:Q4: 2SC35852SC5107 )

TX/RX switch (D3, D4: MA77)

VCO circuit

PLL reference oscillator (X1: CR-671A 15.3 MHz)

Low-pass filter circuit (IC12,16: NJM12904V)

Expander IC

(IC15: BU4094BCFV)

Antenna switching circuit (D1:D9, 1SV307D10: MA77)

RF amplifier (Q15: 3SK293)

(IC2: TA75S01F)

AF amplifier (IC4: TA7368F)

Analog switch

(IC6: BU4066BCFV)

D/A converter (IC9: M62363FP)

Crystal filter (FI1: FL-313)

FM IF IC

(IC3: TA31136FN)

1st mixer (Q19: 3SK272)

PLL IC

(IC1: MB15A02PFV1)

CPU

(IC7: HD6433664A24FP)

EEPROM

(IC11: HN58X2416TI)

2 - 1

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Contents UHF FM Transceivers Repair Notes IntroductionOrdering Parts Table of Contents ‘ General Specifications‘ Transmitter ‘ ReceiverBottom View Inside ViewsMain Unit TOP View Removing the Main Unit Disassembly InstructionsRemoving the Chassis Receiver Circuits Circuit DescriptionTransmitter Circuits General PLL CircuitVCO Circuit PLL CircuitPin Port Description Number Power Supply Circuits Voltage LinePort Allocations 3 D/A Convertor IC IC9 Output Expander IC IC15Preparation Adjustment ProceduresJIG cable Screen display exampeSPE GNDConnection DC power cable connectionsDC Power Supply GND PLL Lock PLL AdjustmentMain VoltageSoftware Adjustment Squelch SensitivityLevel SQLMain Unit Section Parts ListUnit Coil Eljfc R68M-F Array Electrolytic ECEV1CA470SP Connector Accessories Mechanical Parts and DisassemblyChassis Parts Screw abbreviations B0, BT Self-tappingIC-F21S Diodes SEMI-CONDUCTOR InformationTransistor and FET’S Main Unit Board LayoutsIC6 FT1SW-B Unit SW-A and SW-B UnitsTOP View SW-A Unit GND Tled Rled VCC Volin Volout Bottom View SW-A UnitCBI0 CBI1 CBI2 CBI3 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