DUAL BAND FM TRANSCEIVER
i2725E
SERVICE
MANUAL
INTRODUCTION
This service manual describes the latest service information
for the IC-2725E DUAL BAND FM TRANSCEIVER at the
time of publication
DANGER
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 liquids.
DO NOT reverse the polarities of the power supply when
connecting the transceiver.
DO NOT apply an RF signal of more than 20 dBm (100 mW)
to the antenna connector. This could damage the transceiv-
er’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>
1110004310 S.IC M62352GP IC-2725E MAIN UNIT 5 pieces
8810009610 Screw FH M2.6×6 ZK IC-2725E bottom cover 10 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 insu-
lated tuning tool MUST be used for all adjustments.
5. DO NOT keep power ON for a long time when the trans-
ceiver is defective.
6. DO NOT transmit power into a signal generator or a
sweep generator.
7. ALWAYS connect a 50 dB to 60 dB attenuator between
the transceiver and a deviation meter or spectrum ana-
lyzer when using such test equipment.
8. READ the instructions of test equipment thoroughly
before connecting equipment to the transceiver.
To upgrade quality, any electrical or mechanical parts and
internal circuits are subject to change without notice or
obligation.
MODEL
IC-2725E
VERSION
Europe
Italy
SYMBOL
EUR
ITR
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 - 5
4 - 3 PLL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 6
4 - 4 POWER SUPPLY CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 8
4 - 5 PORT ALLOCATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 - 10
SECTION 5 PARTS LIST
SECTION 6 MECHANICAL PARTS AND DISASSEMBLY
SECTION 7 SEMI-CONDUCTOR INFORMATION
SECTION 8 BOARD LAYOUTS
8 - 1 CONTROL UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 1
8 - 2 MAIN UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 - 3
8 - 3 VCO UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 - 5
SECTION 9 BLOCK DIAGRAM
SECTION 10 VOLTAGE DIAGRAMS
10 - 1 CONTROL UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 - 1
10 - 2 MAIN AND VCO UNITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 - 2
1 - 1
SECTION 1 SPECIFICATIONS
All stated specifications are subject to change without notice or obligation.
MGENERAL
• Frequency range :
• Mode : FM, AM (AM range is 118.0 – 135.995 MHz and Rx only for [USA] and [EXP].)
• Nomber of memory channel : 212 (including 2 call channels and 10 scan edges)
• Usable temperature range : –10˚C to +60˚C; +14˚F to +140˚F
• Frequency resolution : 5, 10, 12.5, 15, 20, 25, 30 and 50 kHz
• Frequency stability : ±10 ppm (–10˚C to +60˚C; +14˚F to +140˚F)
• Power supply requirement : 13.8 V DC ±15 % (negative ground)
• Current drain (at 13.8 V DC) : Receive Standby (squelched) 1.2 A
Max. audio output 1.8 A
Transmit at VHF 50 W/UHF 35 W 12.0 A/11.0 A
• Antenna connector : SO-239 (50 Ω)
• DATA connector : Mini DIN 6 pin
• Dimensions : Controller 140(W)×50(H)×27(D) mm; 51⁄2(W)×131⁄32(H)×11⁄16(D) inch
(projections not included) Main unit 140(W)×40(H)×187(D) mm; 51⁄2(W)×19⁄16(H)×73⁄8(D) inch
• Weight : Controller 150 g; 5.29 oz
Main unit 1.4 kg; 3.0 lb
MTRANSMITTER
• Output power : VHF 50 W/25 W/5 W (selectable)
UHF 35 W/25 W/5 W (selectable)
• Modulation system : Variable reactance frequency
• Maximum frequency deviation: ±5.0 kHz
• Spurious emissions : Less than –60 dB
• Microphone connector : 8-pin modular jack (600 Ω)
MRECEIVER
• Receive system : Double-conversion superheterodyne
• Intermediate frequency : 1st IF 38.85 MHz/46.05 MHz
(Left/right side band) 2nd IF 450 kHz/455 kHz
• Sensitivity : Less than 0.18 µV (at 12 dB SINAD)
• Squelch sensitivity : Less than 0.13 µV (at threshold)
• Selectivity (wide/narrow) : More than 12 kHz/–6 dB
Less than 30 kHz/ –60 dB
• Spurious and image rejection : More than 60 dB
• Audio output power (at 13.8 V) : More than 2.4 W at 10% distortion with an 8 Ωload
• External speaker connector : 2-conductor 3.5(d) mm (1⁄8")/8 Ω
VERSION
[EUR]
[ITR]
RX (MHz)
144.000–146.000, 430.000–440.000
144.000–146.000
430.000–434.000, 435.000–438.000
TX (MHz)
144.000–146.000, 430.000–440.000
144.000–146.000
430.000–434.000, 435.000–438.000
SECTION 3 DISASSEMBLY INSTRUCTIONS
• Removing the MAIN unit
➀Unscrew 8 screws A, and remove the cover.
➁Disconnect two cables Bfrom J1 and J2007.
➂Remove the clip c.
AA
B
C
J2007
J1
G
F
G
F
H
E
MAIN UNIT
J
I
➃Unsolder 3 points E.
➄Unscrew 4 screws F.
➅Unsolder 4 points G, and remove the cover H.
➆Unscrew 2 screws I.
➇Unscrew 12 screws J, and remove MAIN unit.
3 - 1
SECTION 8 BOARD LAYOUTS
8-1 CONTROL UNIT
• TOP VIEW
MAIN
BAND
V/MHz
SCAN
M/CALL
MW
MAIN
BAND
V/MHz
SCAN
M/CALL
MW
DUP
MONI TONE
DTMF LOW
PRIO
SQL DIALDIAL SQL
VOL
SET
VOL
PWR
HV6
4
2
to MAIN unit J2006
5
3
1
J2
RDATA
MIC
TDATA
GND
MICE
2
4
6
8to Microphone
1
3
5
7
J1
MICU/D
PTT
MIC
MICIN
8V
EXTMIC
MICE
GND
8 - 1
1-1-3 S-13907HZ-C2
© 2002 Icom Inc.
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
Icom IC-2725E Service Manual
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