Icom IC-718, IC-725B Service Manual

Page 1
Mar. 2010
SERVICE MANUAL ADDENDUM
CONTENTS
REPLACEMENT PAGES . . . . . . . . . . . . . . . . . . . . . . 5–4 and 5–5
PARTS LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
VOLTAGE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . 15
Page 2
Jul. 2009
SERVICE MANUAL ADDENDUM
CONTENTS
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BOARD LAYOUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
VOLTAGE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . 18
Page 3
Oct. 2008
Oct. 2008
SERVICE MANUAL ADDENDUM
CONTENTS
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BOARD LAYOUTS (MAIN, PLL, PA and FILTER UNITS). . . . 12
VOLTAGE DIAGRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Page 4
Oct. 2007
SERVICE MANUAL ADDENDUM
CONTENTS
TRANSMITTER ADJUSTMENTS for PA UNIT "B-5380I". . . . 1
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BOARD LAYOUTS (MAIN, PLL, PA and FILTER UNITS). . . . 13
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
VOLTAGE DIAGRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Page 5
HF TRANCEIVER
iC-718
Page 6

INTRODUCTION

DANGER
This service manual describes the latest service information for the IC-718 HF TRANCEIVER at the time of publication.
To upgrade quality, all electrical or mechanical parts and internal circuits are subject to change without notice or obligation.
MODEL
IC-718
VERSION
U.S.A.
Europe
Italy
France
Spain Other Korea
U.S.A.
SYMBOL
USA EUR
ITA FRA ESP OTH KOR
USA-1
NEVER connect the transceiver to an AC outlet or to a DC
power supply that uses more than 16 V. This will ruin the transceiver.
DO NOT expose the transceiver to rain, snow or any liq-
uids.
DO NOT reverse the polarrities of the power supply when
connecting the tranceiver.
DO NOT apply an RF signal of more than 20 dBm (100
mW) to the antenna connector. This could damage the transceiver’s front end.
ORDERING PARTS
Be sure to include the following four points when ordering replacement parts:
1. 10-digit order numbers
2. Component part number and name
3. Equipment model name and unit name
4. Quantity required
<SAMPLE ORDER>
1110001810 S.IC TA7368F IC-718 MAIN UNIT 1 piece 8810009650 Screw FH BT M3 × 8 NI-ZU IC-718 CHASSIS 6 pieces
Addresses are provided on the inside back cover for your convenience.
REPAIR NOTES
1. Make sure a problem is internal before disassembling the transceiver.
2. DO NOT open the transceiver until the transceiver is disconnected from its power source.
3. DO NOT force any of the variable components. Turn them slowly and smoothly.
4. DO NOT short any circuits or electronic parts. An insulated tuning tool MUST be used for all adjustments.
5. DO NOT keep power ON for a long time when the transceiver is defective.
6. DO NOT transmit power into a signal generator or a sweep generator.
7. ALWAYS connect a 50 dB or 60 dB attenuator between the transceiver and a deviation meter or spectrum analyser when using such test equipment.
8. READ the instructions of test equipment thoroughly before connecting equipment to the transceiver.
Page 7

TABLE OF CONTENTS

SECTION 1 SPECIFICATIONS
SECTION 2 INSIDE VIEWS
SECTION 3 DISASSEMBLY INSTRUCTIONS
SECTION 4 CIRCUIT DESCRIPTION
4 – 1 RECEIVER CIRCUITS ................................................................................................................... 4 – 1
4 – 2 TRANSMITTER CIRCUITS ............................................................................................................ 4 – 4
4 – 3 PLL CIRCUIT ................................................................................................................................. 4 – 5
4 – 4 LOGIC CIRCUITS .......................................................................................................................... 4 – 6
4 – 5 REGULATOR CIRCUITS ................................................................................................................ 4 – 6
SECTION 5 ADJUSTMENT PROCEDURES
5 – 1 PREPARATION BEFORE SEVICING ............................................................................................. 5 – 1
5 – 2 PLL ADJUSTMENTS....................................................................................................................... 5 – 2
5 – 3 TRANSMITTER ADJUSTMENTS...................................................................................................5 – 4
5 – 4 RECEIVER ADJUSTMENTS.......................................................................................................... 5 – 8
5 – 5 SET MODE ADJUSTMENT ............................................................................................................ 5 – 6
SECTION 6 PARTS LIST
SECTION 7 MECHANICAL PARTS AND DISASSEMBLY
SECTION 8 SEMI-CONDUCTOR INFORMATIONS
SECTION 9 BOARD LAYOUTS
9 – 1 MAIN UNIT ..................................................................................................................................... 9 – 1
9 – 2 PLL UNIT ........................................................................................................................................ 9 – 2
9 – 3 LOGIC UNIT ................................................................................................................................... 9 – 3
9 – 4 PHONE BOARD.............................................................................................................................. 9 – 3
9 – 5 MIC BOARD .................................................................................................................................... 9 – 3
9 – 6 VR BOARD ..................................................................................................................................... 9 – 3
9 – 7 FILTER UNIT................................................................................................................................... 9 – 5
9 – 8 PAUNIT .......................................................................................................................................... 9 – 7
SECTION 10 BLOCK DIAGRAM
SECTION 11 WIRING DIAGRAM
SECTION 12 VOLTAGE DIAGRAMS
Page 8

SECTION 1 SPECIFICATIONS

1 - 1
GENERAL
• Frequency coverage : Receive 0.030–29.999999 MHz*
1
Transmit 1.800–1.999 MHz*23.500–3.999 MHz*
2
7.000–7.300 MHz 10.100–10.150 MHz
14.000–14.350 MHz 18.068–18.168 MHz
21.000–21.450 MHz 24.890–24.990 MHz
28.000–29.700 MHz
*1Guaranteed range: 0.5–29.999999 MHz. *2Varies accoding to version.
• Mode : USB, LSB, CW, AM, RTTY (FSK)
• No. of memory Ch. : 101 (99 regular, 2 scan edges)
• Freq. resolution : 1 Hz
• Frequency stability : Less than ±200 Hz from 1 min. to
60 min. after power ON. After that rate of stability less than ±30 Hz/hr at +25˚C (+77˚F). Temperature fluctuations 0˚C to 50˚C (+32˚F to +122˚F) less than ± 350 Hz.
Power supply requirement
: 13.8 V DC ±15 %
(negative ground)
• Current consumption :
Transmit max. power 20.0 A Receive stand-by 1.3 A
max. audio 2.0 A
• Usable temp. range : –10˚C to +60˚C (14˚F to 140˚F)
• Antenna connector : SO-239 (50 Ω)
• Dimensions : 240 (W)
95(H) 239(D) mm
(projection not included) 9
7
16(W) 33⁄4(H) 913⁄32(D) in
Weight : 3.8 kg (8 lb 6 oz)
ACC connector : 13-pin
REMOTE connector : 2-conductor 3.5(d) mm (
1
8")
TRANSMITTER
Modulation system :
SSB Balanced modulation AM Low level modulation
• Output power : SSB/CW/RTTY/FM 2–100 W AM 2–40 W
Spurious emission : Less than –50 dB below peak out-
put power
* spurious frequency ; below 30 MHz: –50 dB,
above 30 MHz: –60 dB
Carrier suppression : More than 40 dB
Unwanted sideband suppression:
More than 50 dB
Mic. connector : 8-pin connector (600 Ω)
KEY connector : 3-conductor 6.5(d) mm (
1
4")
SEND connector : Phono (RCA)
ALC connector : Phono (RCA)
RECEIVER
Receive system : Double-conversion superheterodyne
Sensitivity
(10 dB S/N) :
SSB, CW, RTTY 0.16 µ V*
1
(1.8–29.999999 MHz)
AM 13 µV (0.5–1.799999 MHz)
2.0 µV*1(1.8–29.999999 MHz)
*1Pre-amp 1 ON
Squelch sensitivity : Less than 5.6 µV (SSB)
Selectivity :
SSB, CW, RTTY More than 2.1 kHz/–6 dB
Less than 4.5 kHz/–60 dB
AM More than 6.0 kHz/–6 dB
Less than 20.0 kHz/–40 dB
Spurious and image rejection ratio: More than 70 dB (1.8–29.999999 MHz)
Audio output power : More than 2.0 W
(at 13.8 V DC)
at 10 % distortion with an 8 load
RIT variable range : ±1200 Hz
PHONES connector : 3-conductor 6.5(d) mm (
1
4")
EXT SP connector : 2-conductor 3.5(d) mm (
1
8") 8
All stated specifications are subject to change without notice or obligation.
Page 9
9 - 6
FILTER UNIT
BOTTOM VIEW
The combination of this page and the previous page shows the unit layout in the same configuration as the actual P.C. Board.
Page 10
Count on us!
6-9-16, Kamihigashi, Hirano-ku, Osaka 547-0002, Japan
S-13701MZ-C1
© 2000 Icom Inc.
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