Icom IC-910H service manual Receiver Adjustments

Page 22

5-4 RECEIVER ADJUSTMENTS

Receiver adjustments must be performed after software adjustment (0) and (1). SUB band must be OFF when adjusting MAIN band, or main AF volume (max.counter clockwise) and SQL volume (max. clockwise) must be set when adjusting SUB band.

 

 

 

 

 

MEASUREMENT

 

 

ADJUSTMENT

ADJUSTMENT

ADJUSTMENT CONDITION

 

VALUE

POINT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNIT

 

LOCATION

 

 

UNIT

ADJUST

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: Any

PA

Connect an RF volt-

Maximum level

PA

L521

RECEIVER

 

• Disconnect P501 (PA unit) from J51

 

meter to check point

 

 

 

 

 

PEAK/GAIN

 

on the MAIN unit.

 

 

P501 via

the

JIG

 

 

 

 

 

 

 

• Connect a standard signal generator

 

cable (A).

 

 

 

 

 

 

 

 

 

to [VHF ANT] connector and set as:

 

 

 

 

 

 

 

 

 

 

 

 

Frequency : 146.0000 MHz

 

 

 

 

 

 

 

 

 

 

 

 

Level

: 7.1 mV* (–30 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Receiving

 

 

 

 

 

 

 

–14 dBm

 

R547

 

 

 

 

 

 

 

 

 

 

 

 

After adjustment, connect P501 (PA unit) to J51 on the MAIN unit.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M PEAK

1

• Display frequency: 145.9800 MHz

Rear

Connect an distortion

Minimum audio distor-

MAIN

Adjust

in

(MAIN BAND)

 

• Mode

 

: FM

panel

meter to [EXT

SP]

tion level

 

sequence

 

 

• Connect an SSG to [VHF ANT] con-

 

connector

with

an

 

 

L51,

L52

 

 

nector and set as:

 

 

8 load.

 

 

 

 

s e v e r a l

 

 

Frequency : 145.9800 MHz

 

 

 

 

 

 

 

times.

 

 

 

 

Level

: 3.2 µV* (–97 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : 1 kHz/±5.0 kHz Dev.

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Mode

 

: USB

 

Connect an AC milli-

Maximum noise output

 

L53, L352,

 

 

• Set an SSG as

:

 

volt meter to [EXT

level

 

L353, L354

 

 

Frequency : 145.9815 MHz

 

SP]

connector

with

 

 

 

 

 

 

 

Level

: 0.1 µV* (–127 dBm)

 

an 8 load.

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: 145.9800 MHz

Rear

Connect an AC milli-

1.0 V (0 dB)

Front

main [AF]

TOTAL GAIN

 

• Mode

 

: USB

panel

volt

meter

to [EXT

 

panel

volume

(MAIN BAND)

 

• Set an SSG as

:

 

SP]

connector

with

 

 

 

 

 

 

 

Frequency : 145.9815 MHz

 

an 8 load.

 

 

 

 

 

 

 

 

 

Level

: 1 mV* (–47 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Set an SSG as

:

 

 

 

 

 

100 mV (20 dB of AF

MAIN

R360

 

 

Level

: OFF

 

 

 

 

 

level difference as step

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

1.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M PEAK

1

• Sub display freq. : 145.9800 MHz

Rear

Connect an distortion

Minimum audio distor-

MAIN

Adjust

in

(SUB BAND)

 

• Mode

 

: FM

panel

meter to [EXT

SP]

tion level

 

sequence

 

 

• Connect an SSG to [VHF ANT] con-

 

connector

with

an

 

 

L651, L652

 

 

nector and set as:

 

 

8 load.

 

 

 

 

s e v e r a l

 

 

Frequency : 145.9800 MHz

 

 

 

 

 

 

 

times.

 

 

 

 

Level

: 3.2 µV* (–97 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : 1 kHz/±5.0 kHz Dev.

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Mode

 

: USB

 

Connect an AC milli-

Maximum noise output

 

L653, L851,

 

 

• Set an SSG as

:

 

volt meter to [EXT

level

 

L852, L853

 

 

Frequency : 145.9815 MHz

 

SP]

connector

with

 

 

 

 

 

 

 

Level

: 0.1 µV* (–127 dBm)

 

an 8 load.

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

144 M

1

• Display frequency: 145.9800 MHz

Rear

Connect an AC milli-

1.0 V (0 dB)

Front

sub [AF]

TOTAL GAIN

 

• Mode

 

: USB

panel

volt

meter

to [EXT

 

panel

volume

(SUB BAND)

 

• Set an SSG as

:

 

SP]

connector

with

 

 

 

 

 

 

 

Frequency : 145.9815 MHz

 

an 8 load.

 

 

 

 

 

 

 

 

 

Level

: 1 mV* (–47 dBm)

 

 

 

 

 

 

 

 

 

 

 

 

Modulation : OFF

 

 

 

 

 

 

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Set an SSG as

:

 

 

 

 

 

100 mV (20 dB of AF

MAIN

R857

 

 

Level

: OFF

 

 

 

 

 

level difference as step

 

 

 

 

 

 

• Receiving

 

 

 

 

 

 

 

1.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*This output level of a standard signal generator (SSG) is indicated as SSG’s open circuit.

5 - 4

Image 22
Contents Service Manual Repair Notes IntroductionOrdering Parts EURTable of Contents Specifications GeneralReceiver Main and PLL Units SectionInside Views FM if ICPA 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-102 Voice Synthesizer Unit Installing 1st DSP unit front panel sideInstalling 2nd DSP unit rear panel side UT-106 DSP UnitCR-293 High Stability Crystal Unit Circuit Description Receiver CircuitSquelch Control Circuit Main Unit 6 10 MHz if Circuit Main UnitDemodulator Circuit Main Unit Squelch Circuit Main UnitAGC Circuit Main Unit Transmitter CircuitsNoise Blanker Circuit Main Unit Meter Circuit Main UnitCW Keying Circuit Main Unit Transmit if Amplifier Circuit Main UnitModulation Circuit Main Unit RF Circuit PA UnitPLL Circuits 7 1LO PLL Circuit PLL Circuits8 2LO PLL Circuit Required Test Equipment Adjustment ProceduresPreparation Before Sarvicing ‘ ConnectionsPLL Adjustments Frequency AdjustmentPLL and Main Units Receiver Adjustments L353 R547P501 L354 R360Blanker EXTNoise Main Band OFFCP851 L283L22 CP852Transmitter Adjustments R138 R503C659 R131GND If TotalMain Gain LO LeakCP1613 R504R202 R1613Software Adjustment Software Adjustment MeterNoise SQL Filter CalibrationTX Power HPF OFF DeviationLPF UX-910 Adjustments C332 CP321CP322 R13Power SET APCPre-setting for APC adjustment Front Unit Section Parts ListDisplay Board Resistor ERA3YED VR-A Board Func BoardVR-B Board MIC Board RIT BoardJack Board PLL UnitResistor ERA3YEB Thermistor Tantalum ECST1AD107R Main Unit REG BA09TDiode 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 VARISTOR-B Board DRV BoardBARISTOR-A Board BARISTOR-C Board2UX-910MAIN Unit Main Unit UX-910Resistor RGB3L R15 Resister ERA3YED Tantalum ECST1CC226R CH 1H Connectot 25FMN-BTK Cover Parts Mechanical PartsDisplay Unit Chassis PartsUX-910 Main Unit UnpackingUX-910 Chassis Parts UX-910 UnpackingSEMI-CONDUCTOR Information Transistors and FET’SDTA114 EE TL Diodes MA29BSection 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.