Sony Walkman WM-EX170 User manual

WM-EX170/EX172
Canadian Model
WM-EX170
AEP Model
E Model
WM-EX170/172
SERVICE MANUAL
CASSETTE PLAYER
MICROFILM
SPECIFICATIONS
Model Name Using Similar Mechanism NEW
TapeTransport Mechanism Type MT-WMEX170-114
ManufacturedunderlicensefromDolbyLaboratories
Licensing Corporation.
“DOLBY”andthedouble-Dsymbolaaretrademarks
of Dolby Laboratories Licensing Corporation.
• Power requirements
3V DC batteries R6 (AA) ×2 / External DC 3V power sources
• Dimensions
88.5 ×111.5 ×37.6 mm
(3 1/2×4 1/2×1 1/2inches) (w / h/ d) incl. projecting parts and controls
• Mass
EX170 : Approx. 125 g (4.5 oz) / Approx. 185 g (6.6 oz) incl.
batteries and a cassette
EX172 : Approx. 130 g (4.6 oz) / Approx. 190g (6.8 oz) incl.
batteries and a cassette
• Supplied accessories
Stereo headphones or Stereo earphones (1) / Belt clip (1)
Design and specifications are subject to change without notice.
Photo : WM-EX172

— 2 —
TABLE OF CONTENTS
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron aroud 270˚ C during
repairing.
• Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
• Be careful not to apply force on the conductor when soldering
or unsoldering.
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.
SECTION 1
GENERAL
1. GENERAL ······································································2
2. DISASSEMBLY
2-1. Cabinet (Front) Assy ··························································3
2-2. Main Board ········································································· 4
2-3. Cassette Lid ········································································4
2-4. Mechanism Deck ································································5
2-5. Belt, Motor (Reel/Capstan) ················································5
3. MECHANICAL ADJUSTMENT ······························6
4. ELECTRICAL ADJUSTMENT ································6
5. DIAGRAMS
5-1. Block Diagram ··································································· 7
5-2. Printed Wiring Board (EX170 Model) ·······························9
5-3. Schematic Diagram (EX170 Model) ································11
5-4. Printed Wiring Board (EX172 Model) ·····························13
5-5. Schematic Diagram (EX172 Model) ································15
5-6. IC Block Diagrams ···························································17
6. EXPLODED VIEWS
6-1. Cabinet Section································································· 18
6-2. Main Board Section ··························································19
6-3. Mechanism Section-1 (MT-WMEX170-114) ··················20
6-4. Mechanism Section-2 (MT-WMEX170-114) ··················21
7. ELECTRICAL PARTS LIST ··································· 22
This section is extracted
from instruction manual.
EX172 MODEL

— 3 —
Cassette, lid
Cabinet (front) assy
A
1
Two screws
[Screw (B1.7
× 9), tapping]
SECTION 2
DISASSEMBLY
Note : Follow the disassembly procedure in the numerical order given.
2-1. CABINET (FRONT) ASSY
2 Insert the precision screwdriver
(1.4 mm flat-blade) into the slit
at claw
A and release the claw.
3 Remove the cabinet (front) assy.
(Release all claws
B to L in
alphabetical order.)
•This set can be disassembled in the order shown below.
2-1. CABINET (FRONT) ASSY 2-2. MAIN BOARD
2-3. CASSETTE LID
2-4. MECHANISM DECK 2-5. BELT, MOTOR (REEL/CAPSTA
N)
B
L
K
C
DE
F
G
H
I
J

— 4 —
5 Spring (torsion)
B
A
1
Open the cassette lid.
4 Cassette lid.
2-2. MAIN BOARD
2-3. CASSETTE LID
2 Insert a precision screwdriver
(1.4 mm flat-blade) vertically
into portion
A to release the
hinge plate.
3 Portion B to release the
hinge plate.
1 Head flexible board (CN301)
5 Two claws
6 MAIN board
3 Remove the four solders.
4 Screw (M1.4), toothed lock (WH
)
2 Flexible board (CN302)

— 5 —
2 Two screw [screw (M1.4), special head]
3 Motor (reel/capstan
)
1 Belt
2-4. MECHANISM DECK
2-5. BELT, MOTOR (REEL/CAPSTAN)
1 Insert the precision screwdriver
(1.4 mm flat-blabe) in to the slit
and release two claws.
2 Remove the mechanism deck
in the direction of the arrow.

— 6 —
SECTION 3
MECHANICAL ADJUSTMENT SECTION 4 ELECTRICALADJUSTMENT
PRECAUTION
1. Clean the following parts with a denatured-alcahol-moistened
sweb :
Playback head Pinch roller
Rubber belt Capstan
2. Demagnetize the playback head using a demagnetizer.
3. Do not use a magnetized screwdriver for adjustments.
4. After adjusting, apply screw-locking compound onto the
adjusted parts.
5. Unless specified otherwise, use a specified voltage (3.0V) to
perform the adjustments.
Torqu Measurement
Mode
FWD
FWD
Back Tension
REV
REV
Back Tension
FF
REW
Torqu meter
CQ-102C
CQ-102RC
CQ-201B
Meter reading
20 - 30 g · cm
0.4 - 2.0 g · cm
20 - 30 g · cm
0.4 - 2.0 g · cm
More than 40 g · cm
PRECAUTION
1. Specified voltage : 3.0V
2. Switch position
DOLBY NR switch : OFF (EX172 MODEL)
AVLS switch : NORM
CASSETTESECTION
Test Tape
Tape Speed Adjustmnet
Procedure:
1. PlaybackWS-48A(Tape center part) and adjust RV601 so that
the frequency counter reading becomes 3,000Hz ± 15Hz.
2. Playback WS-48A (Tape top and end).
Check that frequency counter reading is within 1.5% of the
reading of step1.
AdjustmentPoint:
[MAIN BOARD] —CONDUCTOR SIDE —
Type
WS-48A Signal 3kHz, 0dB Purpose Tape SpeedAdjustment
Test tape
WS-48A
(3kHz, 0dB)
Set
16
Ω
PHONES jack
+
–
Frequency counte
r
RV601:Tape speed

WM-EX170/EX172
SECTION 5
DIAGRAMS
5-1. BLOCK DIAGRAM
— 7 — — 8 —
IC301
28
L
R29
32
35 RV301
VOLUME
HP901
PLAYBACK
HEAD
M901
REEL/CAPSTAN
MOTOR
34
24 18
15
23
4
11
13
5
10
19
36
1
8
4LIMIT
NORMAL
PRE + POWER AMP
IC331
DOLBY NR
IC601
MOTOR DRIVE
MAIN BOARD
J302
J301
DC IN 3V
PHONES
S305
AVLS
D150
BATT
S302
(POWER)
17
15
14
4U
W
IN+
13
S/S
V
VREF
5
6
21 22
3
7
RV601
TAPE SPEED
S303
NORM
VREF
PRE
OUT2
L
MIX IN 2L MIX
OUT L
MIX
OUT R
PWR
IN2 L
PWR
IN1 R
HP IN 2L
MIX IN 1R
HP IN 1R
PRE
OUT1
R
VREF
25
6
RV351
HIGH RV352 LOW
S351
MEGA BASS
OFF – ON
14
VREFVREF
S352
DOLBY NR
ON – OFF
S351
MEGA BASS
OFF – ON
VREF
M.B
ON/OFF
LOW
BOOST
GAIN
COM
VCC
AVLS
PWR
OUT
1(R)
PWR
OUT
2(L)
MEGA BASS UNIT MEGA BASS UNIT
EX170 MODELEX172 MODEL
26
(TAPE SELECTOR)
CrO
2 /METAL
EX172 MODEL
EX170 MODEL
EX170
MODEL
EX170
MODEL
IN L
IN R
OUT L
OUT R 20
DRY BATTERY
SIZE "AA"
(IEC DESIGNATION R6)
2PCS, 3V
ON/OFF
• Signal path.
E: PB

WM-EX170/EX172
12
A
B
C
D
E
F
G
H
3456789101112
— 9 — — 10 —
5-2. PRINTED WIRING BOARD
(EX170 MODEL)
Ref. No. Location
D150 H-3
IC301 E-7
IC601 E-10
• Semiconductor
Location
Note on Printed Wiring Board:
•X: parts extracted from the component side.
•b: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
• Abbreviation
CND : Canadian.
EE : East European.
FR : French.
9E : Country of origin is not shown.
16
MEGA BASS UNIT
OFF
ON
4
6
2
DC IN 3V
BLK
ORG
RED
WHT BLK
ORG RED WHT
M901
REEL/CAPSTAN
MOTOR
DRY BATTERY
SIZE "AA"
(IEC DESIGNATION R6)
2PCS, 3V
MAIN BOARD
AVLS
NORM
LIMIT
J302
NORM
CrO
2 /
METAL
BATT
RV301
VOLUME S302
(POWER)
L
R
4
5
3
2
16
PLAY BACK
HEAD
HP901
1-667-710- 11
(11)
1
5
9
10
19 18 15
27
28 36
30
25
LR
16
E,9E MODEL
EXCEPT
E,9E

WM-EX170/EX172
5-3. SCHEMATIC DIAGRAM
(EX170 MODEL)
— 11 — — 12 —
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
• % : indicates tolerance.
•C: panel designation.
•U: B+ Line.
•H: adjustment for repair.
• Total current is measured with no cassette installed.
• Power voltage is dc V and fed with regulated dc power
supply from external power voltage jack.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : PLAY
• Voltagesaretaken witha VOM(Input impedance 10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
E: PB
• Abbreviation
CND : Canadian.
EE : East European.
FR : French.
9E : Country of origin is not shown.

WM-EX170/EX172
12
A
B
C
D
E
F
G
H
3456789101112
— 13 — — 14 —
Ref. No. Location
D150 H-3
IC301 F-7
IC331 F-4
IC601 E-10
• Semiconductor
Location
5-4. PRINTED WIRING BOARD
(EX172 MODEL)
BLK
ORG
RED
WHT
DC IN 3V
BLK ORG RED WHT
M901
REEL/CAPSTAN
MOTOR
DRY BATTERY
SIZE "AA"
(IEC DESIGNATION R6)
2PCS, 3V
MAIN BOARD
AVLS
NORM
LIMIT
J302
BATT
RV301
VOLUME
LR
NORM
CrO2/
METAL
S302
(POWER)
L
R
4
5
3
2
1
1
6
1-667-711- 11
16
(11)
195
MEGA BASS UNIT
RV352
LOW
RV351
HIGH
OFF
ON
ON
OFF
7
6
8
5
4
3
9
1
2
S351
MEGA BASS
S352
DOLBY NR
PLAY BACK
HEAD
HP901
5
9
10
19 18 15
27
28 36
30
25
E,6E,9E MODEL
EXCEPT
E,6E,9E
Note on Printed Wiring Board:
•X: parts extracted from the component side.
•b: Pattern from the side which enables seeing.
(The other layers' patterns are not indicated.)
• Abbreviation
CND : Canadian.
EE : East European.
FR : French.
6E : Central and SouthAmerica.
9E : Country of origin is not shown.