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Transceiver
IC-25A
Maintenance manual
Icom IC-25A Maintenance Manual
144 mhz
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Also See for IC-25A
:
Maintenance manual
(77 pages)
,
Instruction manual
(40 pages)
,
Instruction manual
(36 pages)
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Table Of Contents
77
page
of
77
Go
/
77
Contents
Table of Contents
Troubleshooting
Bookmarks
Table of Contents
Contents
Specifications
Controls and Their Functions
Front Panel
Product View and Control
Rear Panel
Under the Top Cover
Inside Views
Main Unit Side
PLL Unit Side
Block Diagram
Operation
Receiver
Main Unit (RF Circuitry)
Main Unit (if Circuitry)
Transmitter
Microphone Amplification and Modulation Unit
Band-Pass Filter and Younger Stage (YGR) Unit
Main Unit (AF-Amplification Circuitry)
PLL Unit Block Diagram
ALC Unit
Power-Supply Unit
Local-Oscillator Circuitry
PLL Mixer Circuitry
Driver Unit Block Diagram
Loop Filter Circuitry
VCO and Buffer-Amplification Circuitry
Transmission Muting Circuitry
Main Functions of Logic Unit IC's Transistors and Diodes
Operation of Logic Unit IC6 (MB14025)
Up/Down, Scan and External Up/Down Control Circuitry
Frequency Up/Down Circuitry
Microphone Up/Down and Scan Control Circuitry
Priority-Control Circuitry
Scan Operation When Scan Start/Stop Switch Is on
CPU Input-Control and Matrix Circuitry
CPU and Output
Logic Unit IC's
Order of Disassembly
Front Panel Controls
Removal of Front Frame and Pushbuttons
Replacement of Front Panel Pushbuttons
Replacement of Front Panel Controls
Disassembly of Rear Panel
PLL Unit Wiring
Main Unit Wiring
Removal of Circuit Boards
Measuring Instruments for Adjustments
PLL and Driver Unit Parts Layout (PLL Adjustment)
Receiver Adjustments
Measuring Instruments for Adjustment
Reception Sensitivity Adjustment
AF Output Check
Main Unit Parts Layout (Reception Adjustment)
Notes for Transmitter Adjustment
Measuring Instrument for Adjustment
Connection of Measuring Instruments
Main Unit Parts Layout (Transmission Adjustment)
Modulation Adjustment
Main Unit Parts Layout (Modulation Adjustment)
PLL Unit Circuit Diagram and Voltage Chart
Main Unit Circuit Diagram and Voltage Chart
Driver (Logic) Unit
EF Unit Circuit Diagram
PA Unit Circuit Diagram and Voltage Chart
Troubleshooting Guide
Parts List
PLL Unit
Driver Unit
IC Ratings
TC-9123P (FM/AM Synthesizer Tuner PLL)
Pin Connection
Maximum Rating
TC-5082 (Oscillator and 10-Stage Divider)
BA401 (FM/IF Limiter)
MJM4558D (Dual Low Noise Amp)
PC2002 (5.4-W Audio Power Amp)
PC577H (FM-IF Amplifier)
Schematic Diagram
EF Unit
Board Layout
PLL Driver Unit
Main Unit
PA Unit
Unit Layout
Advertisement
Quick Links
1
Controls and Their Functions
2
Microphone Amplification and Modulation Unit
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See also:
Maintenance Manual
,
Instruction Manual
Table of
Contents
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