Icom IC-910H service manual PA Unit

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TX/RX switching relay (RL700: AE5349)

Pre-amplifier (Q507: 3SK177)

RX balanced mixer (Q511, Q512: 2SK1740)

145 MHz power amplifier (Q651, Q652: 2SC5152)

TX balanced mixer Q501, Q502: 2SK302 D502: 1SV286

Varistor-A board

DRV board

• PA UNIT

Pre-amplifier (Q260: 3SK177)

RX balanced mixer (Q220, Q221: 2SC3356)

Varistor-C board

Varistor-B board

440 MHz power amplifier (Q151, Q152: 2SC3102)

TX balanced mixer* (Q1, Q2: 2SK302)

TX double balanced mixer

D190: HSB88WS

L190, L191: 617DB-1010

Drive amplifier (Q131: SRFJ7044)

* Located under side of the point

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Contents Service Manual EUR IntroductionOrdering Parts Repair NotesTable of Contents General SpecificationsReceiver FM if IC SectionInside Views Main and PLL UnitsPA Unit Bottom View TOP ViewPLL IC Opening the transceiver’s case Disassembly and Option InstructionsUX-910 1200MHz Band Unit FL-132/FL-133 CW Narrow Filter Opening the PA unit coverMain SUB UT-106 DSP Unit Installing 1st DSP unit front panel sideInstalling 2nd DSP unit rear panel side UT-102 Voice Synthesizer UnitCR-293 High Stability Crystal Unit Receiver Circuit Circuit DescriptionSquelch Circuit Main Unit 6 10 MHz if Circuit Main UnitDemodulator Circuit Main Unit Squelch Control Circuit Main UnitMeter Circuit Main Unit Transmitter CircuitsNoise Blanker Circuit Main Unit AGC Circuit Main UnitRF Circuit PA Unit Transmit if Amplifier Circuit Main UnitModulation Circuit Main Unit CW Keying Circuit Main UnitPLL Circuits 7 1LO PLL Circuit PLL Circuits8 2LO PLL Circuit ‘ Connections Adjustment ProceduresPreparation Before Sarvicing Required Test EquipmentFrequency Adjustment PLL AdjustmentsPLL and Main Units Receiver Adjustments L354 R360 R547P501 L353Main Band OFF EXTNoise BlankerCP852 L283L22 CP851Transmitter Adjustments R131 R503C659 R138LO Leak If TotalMain Gain GNDR1613 R504R202 CP1613Software Adjustment Meter Software AdjustmentNoise SQL Calibration FilterTX Power HPF OFF DeviationLPF UX-910 Adjustments R13 CP321CP322 C332APC Power SETPre-setting for APC adjustment Front Unit Section Parts ListDisplay Board Resistor ERA3YED VR-A Board Func BoardVR-B Board PLL Unit RIT BoardJack Board MIC BoardResistor ERA3YEB Thermistor Tantalum ECST1AD107R REG BA09T Main UnitDiode DAN222TL Resistor ERA3YKD R364 7030003320 R915 7030003520 Tantalum Temsva 1C 335M-8L Electrolytic ECEV1EA4R7SR Electrolytic Relay Diode HSU88TRF Coil Eljre 15NG-F Resistor ERJ1WYJ181U Resistor ERJ1TYJ102U JB 1H JB 1C Mica BARISTOR-C Board DRV BoardBARISTOR-A Board VARISTOR-B BoardMain Unit UX-910 2UX-910MAIN UnitResistor RGB3L R15 Resister ERA3YED Tantalum ECST1CC226R CH 1H Connectot 25FMN-BTK Chassis Parts Mechanical PartsDisplay Unit Cover PartsUX-910 Unpacking UnpackingUX-910 Chassis Parts UX-910 Main UnitTransistors and FET’S SEMI-CONDUCTOR InformationDTA114 EE TL MA29B DiodesSection Board Layouts Page Icom America Inc 13714HZ-C1

IC-910H specifications

The Icom IC-910H is a highly regarded and versatile transceiver that is designed for amateur radio operators who are particularly interested in V/UHF and microwave communications. Known for its exceptional performance, the IC-910H encompasses a suite of features that make it a standout choice for both casual and dedicated hams.

One of the main features of the IC-910H is its dual-band capability, allowing for simultaneous operation on both 144 MHz (2 meters) and 430 MHz (70 centimeters) bands. This dual operation enables users to engage in various communication modes, including SSB, CW, FM, and digital. Its high frequency stability ensures that users can rely on the transceiver for accurate and consistent transmissions.

The IC-910H is equipped with a high-performance 10 MHz IF filter that improves selectivity and reduces adjacent channel interference. The optional 1.2 GHz module enhances the transceiver’s capabilities, allowing operators to venture into microwave frequencies. This expandability is a significant advantage for users who wish to progress in their amateur radio pursuits.

Another notable aspect of the IC-910H is its large, easy-to-read LCD display, which features various color options for enhanced visibility. The front panel layout is user-friendly, providing quick access to important controls and functions. The built-in DSP (Digital Signal Processing) technology offers noise reduction and filtering capabilities, significantly improving overall audio quality and making weak signals more intelligible.

The transceiver also includes extensive memory functions, with up to 1,000 memory channels available for storing frequencies, modes, and operational settings. Additionally, it supports CTCSS and DCS tones, which facilitate the use of repeater systems and private group communications.

In terms of build quality, the IC-910H features a robust construction designed for durability and long-term use. Its efficient power supply management ensures excellent performance while minimizing heat generation, making it suitable for extended operating sessions.

Overall, the Icom IC-910H is a powerful and feature-rich transceiver that is favored by many amateur radio enthusiasts. With its versatile operating modes, advanced filtering capabilities, and clear display, it stands out as a reliable tool for both casual operators and serious DXers. Its well-thought-out design and comprehensive features make it a valuable addition to any ham's station collection.