Sony ICFM-88-B Service manual
ICF-M88B
SERVICE MANUAL
Ver 1.0 2004.05
SPECIFICATIONS
Time display: 12-hour system
Frequency range:
Band Range Channel step
FM 87.5 - 108 MHz 0.1 MHz
AM 530 - 1 710 kHz 10 kHz
Speaker: Approx. 50 mm (2 inches) dia, 8
Power output: 80 mW (at 10% harmonic distortion)
Power requirements: 3V DC, two size AA (R6) batteries
Dimensions :
Approx. 166.8 × 70 × 95 mm (w/h/d) (6
projecting parts and control.
Mass: Approx. 281.4 g (9.93 oz) incl. batteries / excl. accessories
Supplied accessories:
Mount with wheel sensor (1), Thick/Thin rubber pads (2 each),
Wheel magnet (1), Zip ties (5), Double-sided tape (1), Screws (2)
Design and specifications are subject to change without notice.
531 - 1 710 kHz 9 kHz
5
× 2
⁄
8
7
× 3
⁄
8
3
⁄4 inches) incl.
US Model
Canadian Model
Battery Life (Approx. hours) (JEITA*)
When using FM AM
Sony alkaline size AA (LR6) 66 84
Sony size AA (R6) 23 31
*Measured by JEITA (Japan Electronics and Information Technology Industries
Association) standards.
The actual battery life may vary depending on circumstances of use.
9-877-839-01
2004E05-1
© 2004.05
FM/AM PLL SYNTHESIZED RADIO
Sony Corporation
Personal Audio Company
Published by Sony Engineering Corporation
ICF-M88B
SECTION 1
SERVICING NOTES
TABLE OF CONTENTS
1. SERVICING NOTES ............................................... 2
2. GENERAL ................................................................... 3
3. DISASSEMBLY
3-1. Disassembly Flow ........................................................... 4
3-2. Cabinet (Lower) Block.................................................... 4
3-3. Chassis Assy .................................................................... 5
3-4. MAIN Board.................................................................... 5
4. TEST MODE.............................................................. 7
5. ELECTRICAL ADJUSTMENTS ......................... 8
6. DIAGRAMS
6-1. Printed Wiring Boards – TUNER Section –................... 10
6-2. Schematic Diagram – TUNER Section – ....................... 11
6-3. Printed Wiring Board
– PANEL/POWER SUPPLY Section – ........................... 12
6-4. Schematic Diagram
– PANEL/POWER SUPPLY Section – ........................... 13
7. EXPLODED VIEWS
7-1. Cabinet (Upper) Section .................................................. 16
7-2. Chassis Section................................................................ 17
7-3. Cabinet (Lower) Section.................................................. 18
UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the leadfree mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
• Unleaded solder melts at a temperature about 40 ˚C higher
than ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350 ˚C.
Caution: The printed pattern (copper foil) may peel away if
the heated tip is applied for too long, so be careful!
• Strong viscosity
Unleaded solder is more viscou-s (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
• Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
8. ELECTRICAL PARTS LIST................................ 19
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be
damaged by heat.
2
Location of Controls
SECTION 2
GENERAL
ICF-M88B
This section is extracted from
instruction manual.
FREEZE
PRESET
MHz
kHz
MP H
km/h inc h
mile
mm
MP H
km/h
RADIO P OWER LIGHT ENTER /SELE CT TUNE MODE BAND/SE T
RA
DIO
P
O
W
E
R
LIGHT
E
N
T
E
R
/
S
E
L
E
C
T
T
U
N
E
M
O
D
FM
AM
AM
PM
CLOCK ODO DIST RT AVG MAX
OL
V
T
E
S
/
D
E
N
A
B
J og lever
G
H
I
T
L
E
N
R
T
E
W
O
P
O
I
D
A
R
FM an tennaFM SENS
E
R
/
S
E
L
E
C
T
T
U
N
E
M
O
D
E
B
A
N
D
/
S
E
T
V
O
L
VO L*
DX/LOCAL
* Th ere is a tactile dot beside VOL to show the direction to turn up
the volume.
Setting the Clock
The clock time display of this unit is a 12-hour system.
When the batteries are first installed, AM 12:00 flashes and CLOCK turns on
in the display.
1
Press RADIO POWER to turn off the power.
2
Press MODE/FREEZE repeatedly until CLOCK appears.
3
Hold down ENTER/SELECT for more than 2 seconds until
AM 12 starts flashing.
4
Push the Jog lever towards + or – to adjust the hour, then press
ENTER/SELECT.
The beep sounds and the minute setting starts to flash.
If you hold down the Jog lever towards + or —, the digit changes rapidly.
Midnight is indicated as AM 12:00 and Noon is indicated by PM 12:00.
g
5
Repeat step 4 above to adjust the minutes.
: starts flashing and the clock starts operating.
To set the current time exactly to the second, adjust the minute setting and
then press ENTER/S ELE CT to synchronize it with a time signal (such as
the telephone time signal).
Note
If you do not push the Jog lever towards + or —, or ENTE R/S ELECT within
about 65 seconds, the clock setting mode will be canceled.
3
ICF-M88B
• This set can be disassembled in the order shown below.
3-1. DISASSEMBLY FLOW
SET
3-2. CABINET (LOWER) BLOCK
(Page 4)
3-3. CHASSIS ASSY
(Page 5)
3-4. MAIN BOARD
(Page 5)
SECTION 3
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
3-2. CABINET (LOWER) BLOCK
3
four screws
×
10)
(P1.7
6
cabinet (lower) block
4
battery case lid
2
screw (P1.7 × 10)
1
Slide the hook (battery case lid)
in the direction of arrow,
and open the battery case lid.
5
Remove two solders.
4
3-3. CHASSIS ASSY
5
chassis assy
1
Remove two solders.
4
screw
1
Remove five solders.
ICF-M88B
3
button assy
3-4. MAIN BOARD
1
Remove two solders.
2
two hooks
3
screw
4
MAIN board
1
Remove the solder.
2
hook
5
ICF-M88B
POSITION OF LEAD WIRES
two ditches
boss
DX/LOCAL board
lead wire (gray)
lead wire (red)
lead wire (black)
lead wire (battery terminal (+))
boss
cabinet (lower) block
lead wire (gray)
lead wire (red)
three ditches
6
SECTION 4
TEST MODE
ICF-M88B
EEPROM INITIALIZE MODE
Procedure:
1. Turn on the power to place the set in the standby state.
2. Press the [BAND/SET], [LIGHT] and [MODE/FREEZE] keys
simultaneously for 5 seconds, or short the TP116 (KS0) and
TP117 (KR3) on the key board.
3. When the EEPROM initialize mode is activated, the BEEP
1 is outputted and “dEL” is displayed on the LCD for one
second.
4. After one second elapsed, the BEEP 2 is outputted, and the
EEPROM initialize mode is deactivated and the set returns to
the standby state.
LCD AND KEY TEST MODE
Procedure:
1. Turn on the power to place the set in the standby state.
2. Short the TP115 (KS1) and TP117 (KR3) on the key board.
3. When the LCD and key test mode is activated, the BEEP 1 is
outputted and the LCD becomes all lit state.
LCD display
FREEZE
PRESET
FM
AM
AM
PM
CLOCK ODO DIST RT AVG MAX
4. Each time a key is pressed, the segment assigned to each key
turns off (see below). Also, if the [LIGHT] key is pressed, the
LCD back light turns on. (It turns off at the release of LCD
and ket test mode)
5. When all keys were pressed, the BEEP 2 is outputted, and
the LCD and key test mode is deactivated and the set returns
to the standby state.
MHz
kHz
MPH
km/h inch
mile
mm
MPH
km/h
LCD display-3
AM
PM
CLOCK ODO
LCD display-4
DIST
LCD display-5
FM
AM
LCD display-6
FREEZE
LCD display-7
PRESET
MHz
mm
MPH
km/h
Note 1:The pulse input is ignored during each test mode.
Note 2:In the event that the VDET1 terminal (pin rl of IC101) on the k ey
board detects “L” during each test mode, the test mode is deactivated
and the set returns to the standby state.
Note 3:The amplifier power turns on by the main clock operation to prepare
for the BEEP output during each test mode.
Key Segment Display
POWER S0, S2, S4 below LCD display-1
TUNE MODE S6, S8, S10 below LCD display-2
BAND/SET S12, S14, S16 below LCD display-3
+ S18, S20, S22 below LCD display-4
– S3, S5, S7 below LCD display-5
RESET S9, S11, S13 below LCD display-6
MODE/FREEZE S15, S17, S19 below LCD display-7
ENTER/SELECT S21, S23, S25 below LCD display-8
LIGHT S1, S24 below LCD display-9
LCD display-1
kHz
MPH
km/h inch
LCD display-2
LCD display-8
LCD display-9
Connecting Location:
– KEY BOARD (Conductor Side) –
TP117
(KR3)
TP115
(KS1)
IC101
RT AVG MAX
TP116
(KS0)
mile
7
ICF-M88B
r
r
r
SECTION 5
ELECTRICAL ADJUSTMENTS
0 dB=1 µV
[AM]
Setting:
Function: RADIO
BAND: AM
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level:
as low as possible
[FM]
Setting:
Function: RADIO
BAND: FM
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level:
as low as possible
Put the lead-wire
antenna close to
the set.
set
MAIN board
TP13 (FM IN)
0.01 µF
set
MAIN board
TP10 (RF GND)
MAIN board
TP12 (SP OUT)
level mete
8
Ω
+
–
MAIN board
TP15 (AF GND)
MAIN board
TP12 (SP OUT)
level mete
8
Ω
MAIN board
TP15 (AF GND)
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1 450 kHz
AM VCO VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L1 530 kHz 1.2 ± 0.1 V
Confirmation 1,710 kHz 7.2 ± 0.5 V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
ANT1 590 kHz
CT1 1,490 kHz
FM VCO VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
Confirmation 108.0 MHz 8.9 ± 1.0 V
Confirmation 87.5 MHz 2.3 ± 0.5 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L2 87.5 MHz
CT2 108.0 MHz
Adjustment Location: MAIN board (See page 9)
+
–
digital voltmete
MAIN board
Ω
TP9 (VT)
TP8 (GND)
100 k
• Repeat the procedures in each adjustment several times, and
the tracking adjustments should be finally done by the trimmer
capacitors.
• Remove FM antenna in FM adjustment.
8
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