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IC-720A
Icom IC-720A Manuals
Manuals and User Guides for Icom IC-720A. We have
2
Icom IC-720A manuals available for free PDF download: Maintenance Manual, Instruction Manual
Icom IC-720A Maintenance Manual (125 pages)
Brand:
Icom
| Category:
Transceiver
| Size: 21.74 MB
Table of Contents
Table of Contents
2
Specifications
3
Operating Controls
4
Front Panel
4
Controls under the Access Cover
7
Rear Panel Connections
8
Function
9
ACC Socket Connections
9
Circuit Description
10
Outline
10
Receiving Circuits
10
RF/IF Circuits
10
Operation of Pass-Band Tuning
11
Crystal Filters
11
PBT Circuit
11
AF Circuits
12
AGC Detection Control Circuit
12
BFO Circuit
12
VXO Circuit for PBT and RF Speech Processor
12
Transmitting Circuits
13
AF/IF Circuits
13
PLL Unit
14
Second Local Oscillator
14
Oscillation of 5.12Mhz and Generation of 30.72Mhz Signal
14
Locked Loop
14
Logic Unit
16
Power Circuit
16
Cpu
16
CPU I/O Ports
16
Sensor Signal Processing Circuit
17
Input Matrix Circuit
17
PLL Data Output Circuit
18
Display Circuit
18
Rotary Releay Driving Circuit
19
Switching Signal for Band-Pass Filter
19
Mode Select Signal Circuit
19
Dial Lock
19
Other Circuits
20
SWR Detector and RF Detector
20
ALC Circuit
20
VOX Control and CW Break-In Circuit
20
RTTY Transmitting
21
Block Diagram
22
Inside Views
23
Top View
23
PA Unit
23
Bottom View
24
LPF Unit
24
RF Unit
25
Options Installation
26
Installation of CW Narrow Filter
26
Installation of am Filter
26
Location of CW Narrow Filter
26
Mechanical Parts and Disassembly
27
Parts on Front Panel
27
Front Panel Disassembly
27
Front Panel Switches Disassembly
28
Meter and Display-Tube Assembly
29
Controls and Connector Assembly
29
Front Panel Connectors Location
30
Sensor Disassembly
31
Rear Panel Disassembly
32
Accessory Socket
33
Plug Parts for the Accessory Socket
33
Accessory Socket Assembly
33
ACC Socket Wiring Diagram
33
Terminal Panel Disassembly
34
PA Unit Disassembly
35
Unit PC Board Disassembly
36
Internal Connectors Location
37
Maintenance and Adjustment
38
Measuring Instruments Required for Adjustment
38
PLL Adjustment
39
IF Unit Adjustment
42
Transmitter Adjustment
44
Receiver Adjustment
47
PLL Unit Parts Location
49
IF Unit Parts Location
50
Main Unit Parts Location
52
MIC-G Unit Parts Location
52
RF Unit Parts Location
53
FSW Unit
54
SWR Unit
54
Driver Unit
55
Idling Current Adjustment
55
Logic Unit Voltage Check
56
Logic Unit Voltage Waveforms
57
PLL Unit Voltage Diagram
59
PLL Unit Voltage Waveforms
61
Main Unit Voltage Diagram
62
RF Unit Voltage Diagram
64
IF Unit Voltage Diagram
66
Logic Unit Voltage Diagram
68
Filter Unit Voltage Diagram
69
Driver Unit Voltage Diagram
70
PA Unit Circuit Diagram
71
Sensor Unit Circuit Diagram
72
SWR Unit Circuit Diagram
72
Display Unit Circuit Diagram
73
RTTY Unit Voltage Diagram
73
EF Unit Circuit
74
Troubleshooting
76
Parts List
79
IC Specifications
102
Schematic Diagram
106
IF Unit
112
Unit Layout
113
EF Unit
114
Front Switch Board
115
Main Unit
117
MIC Gain Board
118
Filter Unit
121
Power Amplifier Unit
122
RTTY Unit
123
LDA Unit
123
ACC Unit
124
PA Connector Board
124
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Icom IC-720A Instruction Manual (45 pages)
HF allband transceiver General coverage receiver
Brand:
Icom
| Category:
Transceiver
| Size: 5.6 MB
Table of Contents
Table of Contents
3
Specifications
4
Features
5
Outstanding Receiver Performance
5
Pass-Band Tuning and Speech Processor
5
Additional Circuits
5
Installation
6
Unpacking
6
Recommendations for Installation
6
Power Supply
6
Antenna
7
Ground
7
Microphone
7
CW Key
7
Rtty
8
External Speaker
8
Headphones
8
Cooling Fan
8
Operating Controls
9
Front Panel
9
Multi-Function Meter
10
RF Power Control
10
MIC Gain Control
10
Power Switch
10
Dial Lock Button
11
Tuning Control Knob
11
Mode/Frequency Display
11
Dial Lock Indicator
11
Controls under the Access Cover
12
AGC (Automatic Gain Control) Switch
12
Noise Blanker Switch
12
Attenuator Switch
12
Rear Panel Connections
13
Meter Switch
13
Vox Gain Control
13
SWR Set Control
13
Low Band Antenna Terminal
14
Transverter/Scope Terminal
14
ACC Socket Connections
14
Fuse Holder
14
Operating Instructions
15
How to Tune
15
Frequency Display in each Mode
15
Tuning Knob
15
Tuning Speed Button
16
VFO Switch
16
VFO Equalizing Switch
17
Simplex/Duplex
17
Ham/General Cover Switch
17
Band Up/Down Switches
17
Rit
18
SSB Operation
18
Receiving
18
Noise Blanker
19
Automatic Gain Control
19
How to Use the Vox Circuit
20
CW Operation
20
Transmitting
20
SW Side-Tone
20
RTTY Operation
21
AM Operation
22
General Coverage Receiver
22
Meter Functions
23
WWV Reception
23
Simple Frequency Alignment
23
Satellite Communication
24
Low Band Antenna
24
Receiver Antenna Terminals
24
Transverter Connection
25
Scope Terminal
25
Linear Amplifier Connection
26
Band Control Voltage Chart
26
Circuit Description
27
SWR Unit
27
Low-Pass Filter Unit
27
RF Unit
27
Main Unit
28
Driver Unit
28
PA Unit
28
Logic Unit
28
Logic Unit Block Diagram
29
PLL Unit Block Diagram
29
RTTY Unit
29
LDA Unit
29
Inside Views
30
Top View
30
Bottom View
31
LPF Unit
31
PLL Unit
32
Option Installation
33
Installation of CW Narrow Filter
33
Installation of am Filter
33
Maintenance and Adjustment
34
Measuring Instruments Required for Adjustment
34
Receiver Adjustment
34
BFO Frequency Adjustment
34
P.B.T. Frequency Adjustment
35
Receiver if Gain Adjustment
35
S-Meter Adjustment
35
Transmitter Adjustment
36
Idling Current Adjustment
36
ALC Adjustment
36
Carrier Suppression Adjustment
36
Speech Processor Adjustment
37
AM Modulation Adjustment
37
IC Meter Adjustment
37
Overcurrent APC Adjustment
37
PLL Adjustment
38
Tracking Adjustment
38
2Nd lo Adjustment
38
RIT Frequency Adjustment
38
Trobleshooting
39
Block Diagram
41
Options
42
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