Icom IC-M25EURO User Manual
VHF MARINE TRANSCEIVER
iM25
iM25EURO
S-15208XZ-C1
August 2015
INTRODUCTION
This service manual describes the latest technical information for the IC-M25 and IC-M25EURO
time of publication.
To upgrade quality, any electrical or mechanical parts
and internal circuits are subject to change without notice
or obligation.
v h f t r a n s c e i v e r , at the
MODEL
NAME
IC-M25
IC-M25EURO
IC-M25
IC-M25EURO
IC-M25
IC-M25EURO
VERSION
NAME
VERSION
NUMBER
TX OUTPUT
POWER
USA #01 5W/1W
EXP #02 5W/1W
CHN #03 5W/1W
EUR #05 5W/1W
UK #06 5W/1W
FRG #07
5W/1W
(1W/0.5W)
HOL #08 5W/1W
AUS #09 5W/1W
USA-01 #11 5W/1W
EXP-01 #12 5W/1W
CHN-01 #13 5W/1W
EUR-01 #15 5W/1W
UK-01 #16 5W/1W
FRG-01 #17
5W/1W
(1W/0.5W)
HOL-01 #18 5W/1W
AUS-01 #19 5W/1W
USA-02 #21 5W/1W
EXP-02 #22 5W/1W
CHN-02 #23 5W/1W
EUR-02 #25 5W/1W
UK-02 #26 5W/1W
FRG-02 #27
5W/1W
(1W/0.5W)
HOL-02 #28 5W/1W
AUS-02 #29 5W/1W
(IC-M25)
CAUTION
DO NOT reverse the polarities of the power supply when con-
necting the transceiver.
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 Icom part number
2. Component name
3. Equipment model name and unit name
4. Quantity required
<ORDER EXAMPLE>
1110003491 S.IC TA31136FNG IC-M25 MAIN UNIT 5 pieces
8820001210 Screw 2438 screw IC-M25EURO Top cover 10 pieces
Addresses are provided on the inside back cover for your
convenience.
Icom, Icom Inc. and the Icom logo are registered trademarks of Icom Incorporated (Japan) in Japan, the United States, the
United Kingdom, Germany, France, Spain, Russia, Australia, New Zealand, and/or other countries.
1. Make sure that the problem is internal before disassembling the transceiver.
2. DO NOT open the transceiver until the transceiver is dis-
connected 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 trans-
ceiver is defective.
6. DO NOT transmit power into a Standard Signal Generator
or a Sweep Generator, otherwise the RF power may damage them.
7. ALWAYS connect a 30 dB to 40 dB attenuator between the
transceiver and a Deviation Meter or Spectrum Analyzer,
when using such test equipment.
8. READ the instructions of the test equipment thoroughly
before connecting it to the transceiver.
REPAIR NOTES
TABLE OF CONTENTS
SECTION 1 SPECIFICATIONS
SECTION 2 INSIDE VIEWS
SECTION 3 DISASSEMBLY INSTRUCTION
SECTION 4 BATTERY PACK REPLACEMENT
SECTION 5 CIRCUIT DESCRIPITON
5-1 RECEIVER CIRCUITS ...................................................................................... 5-1
5-2 TRANSMITTER CIRCUITS ............................................................................... 5-2
5-3 FREQUENCY SYNTHESIZER CIRCUITS ....................................................... 5-3
5-4 VOLTAGE BLOCK DIAGRAM ........................................................................... 5-3
SECTION 6 ADJUSTMENT PROCEDURES
6-1 PREPARATION ................................................................................................. 6-1
6-2 FREQUENCY ADJUSTMENT .......................................................................... 6-2
6-3 RECEIVE ADJUSTMENT ................................................................................. 6-3
6-4 TRANSMIT ADJUSTMENT ............................................................................... 6-3
SECTION 7 PARTS LIST
SECTION 8 MECHANICAL PARTS
SECTION 9 BOARD LAYOUTS
SECTION 10 BLOCK DIAGRAM
SECTION 11 VOLTAGE DIAGRAM
SECTION 1 SPECIFICATIONS
M GENERAL
IC-M25 (Except [CHN]) D
• Frequency coverage (MHz):
TX 156.025–157.425
RX 156.050–163.275
• Mode: FM (16K0G3E)
•
Power supply voltage
• Current drain (approximately):
TX (5 W/1.0 W) 2.3 A/0.9 A
Maximum audio (internal SP) 0.30 A
Maximum audio (external SP) 0.20 A
• Frequency stability: ±10 ppm
• Operating temperature:
–20°C to +60°C (–4°F to +140°F)
• Dimensions (projections not included):
56.6 (W) × 134.2 (H) × 30.5 (D) mm,
2.2 (W) × 5.3 (H) × 1.2 (D) inch
• Weight: 220 g, 7.8 oz (approximately)
IC-M25EURO/IC-M25 only [CHN] D
• Frequency coverage (MHz):
TX 156.000–161.450
156.000–161.600 [HOL]
156.025–157.425 [AUS]
RX 156.000–163.425 [EUR], [FRG], [HOL], [UK] and [CHN]
156.300–162.025 [AUS]
• Mode:
FM (16K0G3E)
• Power supply voltage:
3.7 V DC nominal (negative ground)
• Current drain (approximately):
TX (5.0 W/1.0 W/0.5 W*) 2.3 A/0.9 A/0.7 A*
*For only [FRG]
Maximum audio (internal SP) 0.30 A
Maximum audio (external SP) 0.20 A
• Frequency stability:
±1.5 kHz
±10 ppm [AUS]
• Operating temperature:
–15°C to +55°C [EUR], [FRG], [HOL], [UK] and [CHN]
–10°C to +55°C [AUS]
• Dimensions (projections not included):
56.6 (W) × 134.2 (H) × 30.5 (D) mm,
2.2 (W) × 5.3 (H) × 1.2 (D) inch
• Weight (approximately):
220 g, 7.8 oz (including the supplied antenna and belt clip)
: 3.7 V DC nominal (negative ground)
(including the supplied antenna and belt clip)
[EUR], [FRG], [UK] and [CHN]
[EUR], [FRG], [HOL], [UK] and [CHN]
M TRANSMITTER
IC-M25 (Except [CHN]) D
• Output power: 5 W (approximately)/1 W
• Modulation system: Variable reactance frequency modulation
• Maximum frequency deviation:
±5 kHz
• Adjacent channel power:
70 dB
• Spurious emissions: –68 dBc typical
• Residual modulation: 40 dB
• Audio frequency response:
+1 dB to –3 dB of 6 dB octave from 300–3000 Hz
IC-M25EURO/IC-M25 only [CHN] D
• Output power: 5 W (approximately)/1 W/0.5 W*
*For only [FRG]
• Modulation system: Variable reactance frequency modulation
• Maximum frequency deviation:
±5 kHz
• Adjacent channel power:
70 dB
• Spurious emissions:
0.25 µW
0.25 µW typical [AUS]
• Residual modulation: 40 dB
• Audio frequency response:
+1 dB to –3 dB of 6 dB octave from 300–3000 Hz
[EUR], [FRG], [HOL], [UK] and [CHN]
M RECEIVER
IC-M25 (Except [CHN]) D
• Sensitivity : 0.25 µV (–12 dBµ) typical (at 12 dB SINAD)
• Squelch sensitivity: 0.25 µV (–12 dBµ) typical (at threshold)
• Intermodulation: 70 dB typical
• Spurious response: 70 dB typical
•
Adjacent channel selectivity
70 dB typical
• Audio output impedance:
12 Ω (internal speaker)
4 Ω (external speaker)
• Audio output power: Internal SP 0.55 W typical
(at 10% distortion) External SP 0.30 W typical
IC-M25EURO/IC-M25 only [CHN] D
• Sensitivity : –6 dBµ emf typical (at 20 dB SINAD)
• Squelch sensitivity: –6 dBµ emf typical (at threshold)
• Intermodulation: 68 dB [EUR], [FRG], [HOL], [UK] and [CHN]
65 dB [AUS]
• Spurious response: 70 dB [EUR], [FRG], [HOL], [UK] and [CHN]
65 dB [AUS]
•
Adjacent channel selectivity
70 dB [EUR], [FRG], [HOL], [UK] and [CHN]
65 dB [AUS]
• Audio output impedance:
12 Ω (internal speaker)
4 Ω (external speaker)
• Audio output power: Internal SP 0.55 W typical (at 1 kHz)
(at 10% distortion) External SP 0.20 W
:
:
1-1
SECTION 2 INSIDE VIEWS
• MAIN UNIT
(TOP VIEW)
LOCK VOLTAGE BUFFER
(IC400)
AF SW
(IC260)
LITHIUM BATTERY CHARGER
(IC601)
???????
(???)
???????
(???)
???????
(???)
2-1
VCO
• MAIN UNIT
(TOP VIEW)
???????
(???)
D/A CONVERTER
(IC190)
AF AMP
(IC364)
AF POWER AMP
(IC362)
CPU CLOCK
(X360)
EEPROM
(IC340)
DUAL OP AMP
(IC365)
1st IF FILTER
(FI151)
PLL IC
(IC1)
REFERENCE
FREQUENCY
OSCILLATOR
(X1)
DISCRIMINATOR
(X170)
2nd IF FILETR
(FI170)
IF IC
(IC170)
DRIVE AMP
(Q53)
???????
(???)
RESET
(IC341)
+3 V REGULATOR
(IC220)
QUAD OP AMP
(IC200)
???????
(???)
???????
(???)
TX POWER AMP
(Q54)
1st IF FILTER
(FI150)
TX POWER AMP
(Q55)
???????
(???)
???????
(???)
2-2
CLAMP CABLE
INLINE CABLE
ｲﾝﾗｲﾝｹｰﾌﾞﾙ
フラット
ケーブル
フラット
ケーブル
ロックをはずすまっすぐ引き抜く
フラットケーブル
FLAT CABLE
Lift up
flat cable
フラットケーブル
起こす
フラットケーブル
FLAT
CABLE
クランプケーブル
フラット
ケーブル
フラット
ケーブル
SPEAKER
CABLE
スピーカー
ケーブル
UNSOLDER
Solder
remover
ハンダ除去
ﾊﾝﾀﾞ吸取器
Remove with;
flat cable
Release the locks
Pull straight
FLAT CABLE
Flat cable
Flat cable
BE CAREFUL about the locks.
COAXIAL CABLE
同軸ケーブル
Front panel
MAIN UNIT
CLAMP CABLE
FLAT
CABLE
クランプケーブル
フラット
ケーブル
フラット
ケーブル
UNSOLDER
Solder
remover
ハンダ除去
ﾊﾝﾀﾞ吸取器
Remove with;
“ICOM Driver (A)” (8960000020)
“ICOM Driver (AA)” (8960000510)
“ICOM Driver (AE)” (8960000540)
“ICOM Driver (AG)” (8960000560)
“ICOM Driver (G)” (8960000080)
“ICOM Driver (I)” (8960000010)
“ICOM Driver (K)” (8960000110)
“ICOM Driver (K2)” (8960000112)
“ICOM Driver (L2)” (8960000171)
“ICOM Driver (M)” (8960000240)
“ICOM Driver (Q)” (8960000370)
“ICOM Driver (R)” (8960000320)
“ICOM Driver (S)” (8960000410)
“ICOM Driver (T)” (8960000400)
“ICOM Driver (U)” (8960000420)
“ICOM Driver (Y)” (8960000460)
Front panel
MAIN UNIT
FFC
FLAT
CABLE
フラット
ケーブル
フラット
ケーブル
UNSOLDER
Solder
remover
UNSOLDER
Solder
remover
ハンダ除去
ﾊﾝﾀﾞ吸取器
Remove with;
Remove with;
“ICOM Driver (A)” (8960000020)
“ICOM Driver (AA)” (8960000510)
“ICOM Driver (AE)” (8960000540)
“ICOM Driver (AG)” (8960000560)
“ICOM Driver (G)” (8960000080)
“ICOM Driver (I)” (8960000010)
“ICOM Driver (K)” (8960000110)
“ICOM Driver (K2)” (8960000112)
“ICOM Driver (L2)” (8960000171)
“ICOM Driver (M)” (8960000240)
“ICOM Driver (Q)” (8960000370)
“ICOM Driver (R)” (8960000320)
“ICOM Driver (S)” (8960000410)
“ICOM Driver (T)” (8960000400)
“ICOM Driver (U)” (8960000420)
“ICOM Driver (Y)” (8960000460)
Front panel
MAIN UNIT
FFC
CABLE
フラット
ケーブル
フラット
ケーブル
UNSOLDER
Solder
remover
“ICOM Driver (AG)” (8960000560)
“ICOM Driver (G)” (8960000080)
“ICOM Driver (I)” (8960000010)
“ICOM Driver (K)” (8960000110)
“ICOM Driver (K2)” (8960000112)
“ICOM Driver (L2)” (8960000171)
“ICOM Driver (M)” (8960000240)
“ICOM Driver (Q)” (8960000370)
“ICOM Driver (R)” (8960000320)
“ICOM Driver (S)” (8960000410)
“ICOM Driver (T)” (8960000400)
“ICOM Driver (U)” (8960000420)
“ICOM Driver (Y)” (8960000460)
Front panel
MAIN UNIT
MAIN UNIT
3 screws
CHASSIS
CLAMP CABLE
ｲﾝﾗｲﾝｹｰﾌﾞﾙ
FFC
フラット
ケーブル
フラット
ケーブル
ロックをはずすまっすぐ引き抜く
フラットケーブル
FLAT CABLE
Lift up
flat cable
フラットケーブル
起こす
フラットケーブル
FLAT
CABLE
クランプケーブル
フラット
ケーブル
フラット
ケーブル
スピーカー
ケーブル
remover
UNSOLDER
Solder
remover
ハンダ除去
ﾊﾝﾀﾞ吸取器
Remove with;
flat cable
Release the locks
Pull straight
FLAT CABLE
Flat cable
Flat cable
BE CAREFUL about the locks.
同軸ケーブル
Sensor connector
Rear panel
Front panel
MAIN UNIT
3 screws
FFC
フラット
ケーブル
フラット
ケーブル
ロックをはずすまっすぐ引き抜く
フラットケーブル
フラットケーブル
起こす
フラットケーブル
クランプケーブル
フラット
ケーブル
フラット
ケーブル
UNSOLDER
Solder
remover
Rear panel
6 screws
Front panel
MAIN UNIT
MAIN UNIT
3 screws
CHASSIS
SPEAKER
CABLE
SECTION 3 DISASSEMBLY INSTRUCTION
1. Removing the MAIN UNIT
1) Remove the 6 screws from the rear panel.
2) Carefully separate the rear panel, and turn it over in
order to disconnect the battery connector and the
sensor connector.
3) Remove the 6 screws from the MAIN UNIT.
4) Disconnect the speaker cable from the MAIN UNIT.
5) Lift the MAIN UNIT with CHASSIS out of the front
2. Removing the CHASSIS
1) Remove the solder from the antenna connector
2) Disconnect the FFC from the MAIN UNIT.
3) Remove the 3 screws from the MAIN UNIT, and
panel.
conductor.
then remove the CHASSIS.
3-1
SECTION 4 BATTERY PACK REPLACEMENT
Ferrite core
Indication lines
Doubled-sided tapes
(Supplied in pair)
Glue
Manufacture: Cemedine Inc.
Name: Super-X
3 to 4 mm
(1/8 to 5/32 inches)
Ferrite core
Glue
Manufacture: Cemedine Inc.
Name: Super-X
3 to 4 mm
(1/8 to 5/32 inches)
Doubled-sided tapes
(Supplied in pair)
Sensor connector
Rear panel
Doubled-sided tapes
(Supplied in pair)
Sensor connector
Rear panel
Ferrite core
Indication lines
Glue
Manufacture: Cemedine Inc.
Name: Super-X
3 to 4 mm
(1/8 to 5/32 inches)
Indication lines
NOTE:
• Before the disassembly, dry the transceiver if it is wet.
• Dispose the old battery pack according to the laws in your
area.
1. Removing the old battery pack
1) Remove the 6 screws from the rear panel.
2) Carefully separate the rear panel and turn it over in
order to disconnect the battery connector and the
red sensor connector.
2. Installing the new battery pack
1) Glue the ferrite core to x its position.
2) Separate the double-sided tapes, which are supplied with the battery pack.
3) Apply the double-sided tapes in the position as
shown below, and then peel the protect sheets.
Pull the old battery pack off the rear panel.
3)
If the double-sided tape is adherent to the rear panel, re-
•
move it.
4) Apply the new battery pack in the position on the
rear panel as shown below.
5) Re-assemble the transceiver.
4-1
SECTION 5 CIRCUIT DESCRIPTION
LPF
ANT
SW
ANTENNA
BPF
RF
AMP
BPFBPF
BPFBPF
To 1st mixerFrom RF AMP
D131
D
TX CIRCUITS
92
D52
Q90
D93
D90
D130
T1CON
LPF
ANT
SW
ANTENNA
BPF
RF
AMP
BPFBPF
IF
AMP
BPFBPF
21.7MHz
1st IF signal
FI150,
Q151
To IF IC
To 1st mixerFrom RF AMP
1st LO signals
from VCO
D131
D
TX CIRCUITS
92
D52
Q90
Q150
FI151
D93
D90
D130
T1CON
BPF
RF
AMP
BPFBPF
IF
AMP
X170
450KHz
BPF
LPF
LPF
AF
AMP
X1
21.25MHz
AF
MUTE
21.7MHz
1st IF signal
FI150,
Q151
To IF IC
From 1st IF AMP
To 1st mixerFrom RF AMP
1st LO signals
from VCO
D131
TX CIRCUITS
Q90
IC1
PLL IC
DE ENPHA
IF IC
D/A IC
SPO
AFOUT
J250
Q150
IC170
FI170
450KHz
IC190
IC362
IC365
VOLIN
VOL
BEEP
De-emphasis
R286, C285
SQLO
SQLI
RSSI
NOISE LEVEL
21.25 MHz
2ND LO signal
DET
Int. SP
Ext. SP
FI151
D93
D130
IC260D
DETMS
SP1
5-1 RECEIVER CIRCUITS
RF CIRCUITS
The RF circuits consist of RF filters, antenna switch, RF
amplier (RF AMP) and so on. The received signal is extract
ed and amplified in the RF circuits.
• ANTENNA SWITCHING CIRCUIT
The RF signal from the antenna is passed through the LPF
(L81, L82, C83–C86 and C89), antenna SW (D52, D90, L90,
C90 and C91) and 2-staged tuned BPF (D92, D93, L92,
L93, C95, C97–C100 and C117), and then applied to the RF
AMP (Q90).
• RF AMPLIFIER
The filtered RX signal is amplified by the RF AMP (Q90)
and passed through another 2-staged BPF (D130, D131,
L96, L97, C109, C110 and C112–L115) to remove unwant-
ed signals. The filtered signal is applied to the 1st mixer
(Q150).
• RF CIRCUITS
2ND IF AND DEMODULATOR CIRCUITS
IC170 is an IF IC which contains the 2nd local oscillator,
2nd mixer, limiter and quadrature detector in its package.
The 21.25 MHz reference frequency signal from the PLL
IC (IC1, pin 9) is applied to the IF IC (IC170, pin 2) as the
2nd LO signal, and it is mixed with 21.7 MHz 1st IF signal
from the 1st IF AMP (Q151), resulting in the 450 kHz 2nd IF
signal. The 450 kHz 2nd IF signal is output from the pin 3 of
IC170.
The 2nd IF signal is filtered by the external ceramic filter
(FI170) which extracts the 450 kHz signal, and then applied
to the internal quadrature detector.
The demodulated AF signal is output from the pin 9.
The quadrature detector is a frequency demodulator which
uses a discriminator (X170) as a phase delayer.
SQUELCH CIRCUIT
A portion of AF signal from the IF IC is adjusted in level by
the D/A converter (IC190), and then applied to the noise
amplifier (IC170, R174–R176, C179 and C180).
Only noise components (approximately 30 kHz signal) are
amplified by the noise amplifier, and then rectified by the
internal noise detector to be converted into DC voltage,
which represents the noise level. The voltage is output from
the pin 14 of IC170, and then applied to the A/D port of the
CPU (IC360, pin 33).
1ST IF CIRCUITS
The RX signal is mixed with the 1st LO signal at the 1st
mixer (Q150), resulting in the 21.7 MHz 1st IF signal. The
converted 1st IF signal is filtered by the crystal filters (FI150
and F151) to remove unwanted out-of-band signals.
The filtered 1st IF signal is amplified by the 1st IF AMP
(Q151), and then applied to the IF demodulate IC (IC170,
pin 16).
• 1ST IF CIRCUITS
The CPU (IC360) compares the applied voltage and squelch
reference level to control the audio signal ON/OFF (emits/
mutes).
RX AF CIRCUITS
The demodulated AF signal from the IF demodulate IC (IC170,
pin 9) is passed through the AF mute SW (IC260D) and LPF
(IC365). The filtered AF signal is de-emphasized by R286 and
C285 to obtain –6 dB/octave of frequency response, and then
applied to the D/A converter (IC190) to be adjusted in level.
The level-adjusted AF signal is amplified by the AF AMP (IC364)
and AF power amplifier (IC362), and then applied to the speaker (CHASSIS: SP1).
• 2ND IF, DEMODULATOR AND RX AF CIRCUITS
5-1
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