Icom IC-910H service manual PLL Adjustments, Frequency Adjustment

Page 20

5-2 PLL ADJUSTMENTS

 

 

 

 

MEASUREMENT

 

 

ADJUSTMENT

ADJUSTMENT

ADJUSTMENT CONDITION

 

VALUE

POINT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNIT

LOCATION

 

UNIT

ADJUST

 

 

 

 

 

 

 

 

30.2 MHz

1

• Display frequency: Any

PLL

Connect an RF volt-

–10 dBm (or more than

PLL

R570

LEVEL

 

• Receiving

 

 

meter or

spectram

–11.5 dBm, when R570

 

 

 

 

 

 

 

analyzer

to

check

is in maximum posi-

 

 

 

 

 

 

 

point J541.

 

tion.)

 

 

 

 

 

 

 

 

 

 

REFERENCE

1

• Display frequency: Any

PLL

Connect an RF volt-

Maximum level

PLL

Adjust in

FREQUENCY

 

• Receiving

 

 

meter or

spectram

(–13 dBm to –7dBm)

 

sequence

 

 

 

 

 

analyzer

to

check

 

 

L551, L552

 

 

 

 

 

point P551.

 

 

 

s e v e r a l

 

 

 

 

 

 

 

 

 

 

times.

 

 

 

 

 

 

 

 

 

2

This adjustment must be performed

 

Connect a frequency

60.400000 MHz

 

The trimmer

 

 

at 5 minutes later after power ON.

 

counter

to

check

 

 

capacitor of

 

 

 

 

 

point P551.

 

 

 

X512.

 

 

 

 

 

 

 

 

 

 

144M LOCK

1

• Display frequency: 173.9800 MHz

PLL

Connect

a

digital

2.7 V

PLL

L193

VOLTAGE

 

• Mode

: USB

 

multimeter or oscillo-

 

 

 

 

 

• Receiving

 

 

scope to check point

 

 

 

 

 

 

 

 

CP100.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Display frequency: 136.0200 MHz

 

 

 

 

0.6 V to 1.6 V

 

Verify

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

• Display frequency: 155.0000 MHz

 

Connect an RF volt-

–10 dBm to –4 dBm

 

Verify

 

 

• Receiving

 

 

meter to check point

 

 

 

 

 

 

 

 

P251.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

440M LOCK

1

• Display frequency: 479.9800 MHz

PLL

Connect

a

digital

3.4 V

PLL

C402

VOLTAGE

 

• Mode

: USB

 

multimeter or oscillo-

 

 

 

 

 

• Receiving

 

 

scope to check point

 

 

 

 

 

 

 

 

CP300.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

• Display frequency: 420.0200 MHz

 

 

 

 

0.5 V to 1.5 V

 

Verify

 

 

• Receiving

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

• Display frequency: 450.0000 MHz

 

Connect an RF volt-

–16 dBm to –10 dBm

 

Verify

 

 

• Receiving

 

 

meter to check point

 

 

 

 

 

 

 

 

P421.

 

 

 

 

 

 

 

 

 

 

 

 

 

MAIN BFO

1

• Display frequency: Any

PLL

Connect an RF volt-

–11 dBm to –5 dBm

PLL

Verify

LEVEL

 

• Mode

:USB

 

meter to check point

 

 

 

 

 

• Receiving

 

 

P601.

 

 

 

 

 

 

 

 

 

 

 

 

 

SUB BFO

2

• Sub display freq. : Any

PLL

Connect an RF volt-

–11 dBm to –5 dBm

PLL

Verify

LEVEL

 

• Mode

:USB

 

meter to check point

 

 

 

 

 

• Receiving

 

 

P701.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5-3 FREQUENCY ADJUSTMENT

 

 

 

 

MEASUREMENT

 

ADJUSTMENT

ADJUSTMENT

ADJUSTMENT CONDITION

VALUE

POINT

 

 

 

 

 

 

 

 

 

 

UNIT

LOCATION

 

UNIT

ADJUST

 

 

 

 

 

 

 

 

FM TX-LO

1

• Display frequency: Any

MAIN

Connect a frequency

10.85000 MHz

MAIN

L255

FREQUENCY

 

• Mode

: FM

 

counter to check

 

 

 

 

 

• Disconnect P501, P502 (PA unit)

 

point CP51.

 

 

 

 

 

from J51 and J52 on the MAIN unit.

 

 

 

 

 

 

 

• Apply no audio signals to [MIC]

 

 

 

 

 

 

 

connector.

 

 

 

 

 

 

 

 

• Transmitting

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

After adjustment, connect P501, P502 (PA unit) to J51, J52 on the MAIN.

5 - 2

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Page 19 Page 21
Contents Service Manual Introduction Ordering PartsRepair Notes EURTable of Contents Specifications GeneralReceiver Section Inside ViewsMain and PLL Units FM if ICPA Unit PLL IC TOP ViewBottom View UX-910 1200MHz Band Unit Disassembly and Option InstructionsOpening the transceiver’s case Main SUB Opening the PA unit coverFL-132/FL-133 CW Narrow Filter Installing 1st DSP unit front panel side Installing 2nd DSP unit rear panel sideUT-102 Voice Synthesizer Unit UT-106 DSP UnitCR-293 High Stability Crystal Unit Circuit Description Receiver Circuit6 10 MHz if Circuit Main Unit Demodulator Circuit Main UnitSquelch Control Circuit Main Unit Squelch Circuit Main UnitTransmitter Circuits Noise Blanker Circuit Main UnitAGC Circuit Main Unit Meter Circuit Main UnitTransmit if Amplifier Circuit Main Unit Modulation Circuit Main UnitCW Keying Circuit Main Unit RF Circuit PA UnitPLL Circuits 8 2LO PLL Circuit PLL Circuits7 1LO PLL Circuit Adjustment Procedures Preparation Before SarvicingRequired Test Equipment ‘ ConnectionsPLL Adjustments Frequency AdjustmentPLL and Main Units Receiver Adjustments R547 P501L353 L354 R360EXT NoiseBlanker Main Band OFFL283 L22CP851 CP852Transmitter Adjustments R503 C659R138 R131If Total Main GainGND LO LeakR504 R202CP1613 R1613Software Adjustment Software Adjustment MeterNoise SQL Filter CalibrationTX Power LPF DeviationHPF OFF UX-910 Adjustments CP321 CP322C332 R13Power SET APCPre-setting for APC adjustment Display Board Section Parts ListFront Unit Resistor ERA3YED VR-B Board Func BoardVR-A Board RIT Board Jack BoardMIC 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 DRV Board BARISTOR-A BoardVARISTOR-B Board BARISTOR-C Board2UX-910MAIN Unit Main Unit UX-910Resistor RGB3L R15 Resister ERA3YED Tantalum ECST1CC226R CH 1H Connectot 25FMN-BTK Mechanical Parts Display UnitCover Parts Chassis PartsUnpacking UX-910 Chassis PartsUX-910 Main Unit 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.
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