Sony Walkman ICF-C121 User manual

MICROFILM
SERVICE MANUAL
FM/AM CLOCK RADIO
US Model
Canadian Model
E Model
SPECIFICATIONS
ICF-C121
FEATURES
Ver 1.2 1999. 11
With SUPPLEMENT-1
(9-925-799-81)
With SUPPLEMENT-2
(9-925-799-82)

– 2 –
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE !
SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE
DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIÈCES SONY DONT LES
NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK !OR DOTTED
LINE WITH MARK !ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs,
screws, and all other exposed metal parts for AC leakage.
Check leakage as described below.
LEAKAGE TEST
TheAC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microampers.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’instructions to use these
instruments.
2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The “limit” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2VAC range are suit-
able. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
1.5 k Ω 0.15 µ FAC
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
SECTION 1
SERVICING NOTES
Mark 1 Mark 2 Center
frequency
red — 10.70MHz
blue — 10.67MHz
orange — 10.73MHz
black — 10.64MHz
white — 10.76MHz
white white 10.75 MHz
yellow — 10.79 MHz
HOW TO CHANGE THE FM CERAMIC FILTERS
This model is used two ceramic filters of CF1 and CF3.
You must use same type of color marked ceramic filters in order
to meet same specifications.
Therefore, the ceramic filter must change two pieces together since
it's supply two pieces in one package as a spare parts.
CF1
mark 2
CF3
mark 2
mark 1
CORD DRESSING
(POWER, ANTENNA, BATTERY)
1) Connect the power cord, antenna cord, and battery cord as
shown in the figure.
2) Mount the chassis with screws (PTP3 ×10).
Note: Tighten completely the screws (PTP3 ×10).
battery cord
screw (PTP3
× 10)
antenna cord
power cord
chassis

– 3 –
SECTION 2
GENERAL This section is extracted from
instruction manual.

– 4 –
Note: Follow the assembly procedure in the numerical order given.
SECTION 3
DIAL POINTER SETTING
1 pointer
5 As shown in figure,
marking
A of TUNE
knob and marking
B
of VOL knob setting.
4
screw
(P3
× 10)
8 RADIO board
2 Set the pointer to
the guide line.
3 chassis
7 Turn CV1 and RV1 shaft in
the arrow direction fully.
6 speaker
pointer guide line
knob (TUNE)
knob (VOL)
marking
A
CV1
RV1
RADIO board
(Conductor Side)
marking B

– 5 – – 6 –
SECTION 4
ELECTRICAL ADJUSTMENTS
[FM]
Setting:
BAND switch: FM
[AM]
Setting:
BAND switch: AM
Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally done
by the trimmer capacitors.
FM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L4 CT4
86.5 MHz 109.5 Hz
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
CT3
Frequency max
AM FREQUENCY COVERAGE ADJUSTMENT
Adjust for a maximum reading on level meter.
L2 CT2
520 kHz 1,650 kHz
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 CT1
600 kHz 1,400 kHz
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1
455 kHz
+
–
FM RF SSG
± 22.5 kHz frequency
deviation by 400 Hz
signal FM lead wire antenna terminal
speaker terminal
0.01 µ Fset
level mete
r
+
–
AM RF SSG
Put the lead-wire
antenna close to
the set.
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
set
speaker terminal
level meter
• Adjusting Location: RADIO board (Component Side)
Clock Frequency Check
Confirm that the reading on the frequency counter is 900 Hz.
If frequency is higher, change capacitor value of C101.
If frequency is lower, change resistor value of R101.
+
–
frequency counter
10 pF IC101 pin
@¶
+ 200
– 100
T1:AM IF
ADJUSTMENT
L1:AM TRACKING
ADJUSTMENT CT3:FM TRACKING
ADJUSTMENT
CT1:AM TRACKING
ADJUSTMENT
CT4:FM FREQUENCY
COVERAGE
ADJUSTMENT
CT2:AM FREQUENC
Y
COVERAGE
ADJUSTMENT
L4:FM FREQUENCY
COVERAGE
ADJUSTMENT
L2:AM FREQUENCY
COVERAGE
ADJUSTMENT
IC1

– 7 – – 8 –
ICF-C121 SECTION 5
DIAGRAMS
5-1. PRINTED WIRING BOARDS
• Semiconductor
Location
Ref. No. Location
D101 F-4
D201 F-6
D202 F-6
D203 C-7
D204 G-4
D205 G-3
IC1 D-4
IC101 G-4
LED101 H-4
Q1 F-2
Q201 D-6
Q202 D-7
Note on Printed Wiring Boards:
•X: parts extracted from the component side.
•Y: parts extracted from the conductor side.
•W: indicates side identified with part number.
•¢: internal component.
•b: Pattern from the side which enables seeing.

5-2. SCHEMATIC DIAGRAM
– 9 – – 10 –
ICF-C121
• IC Block Diagram
IC1 CXA1019S
12 3 45 6 7 8 9 10 1514131211
FM
DISCRIMINATOR
AF POWER AMP AM FE FM IF
TUNING
METER
AM IF DET AGC
FM FE
23 22 21 202425 19 18 17 1629 28 27 2630
GND GND AF OUT VCC RIPPLE FILTER AF IN DET OUT AFC AGC AFC AGC IF GND METER N.C FM IF IN AM IF IN FM/AM BAND SELECT
FM/AM
IF OUT
FE GND
N.C
AM RF IN
FM RF
REG OUT
FM OSC
FM RF IN
AFC
AM OSC
VOL
NF
FM DISCRI
GND GND
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.
•¢: internal component.
•C: panel designation.
•U: B+ Line.
•H: adjustment for repair.
• Voltages are dc with respect to ground under no-signal
(detuned) conditions.
no mark : FM
( ) : AM
∗: Impossible to measure
• Voltagesare takenwithaVOM (Inputimpedance10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
F: FM
f: AM
Note:
The components identi-
fied by mark !or dotted
linewithmark!arecriti-
cal for safety.
Replace only with part
number specified.
Note:
Lescomposantsidentifiéspar
une marque !sont critiques
pour la sécurité.
Ne les remplacer que par une
piéce portant le numéro
spécifié.

– 11 – – 12 –
SECTION 6
EXPLODED VIEW
Les composants identifiés par une
marque !sont critiques pour la
sécurité.
Ne les remplacer que par une pièce
portant le neméro spécifié.
The components identified by
mark !or dotted line with mark
!are critical for safety.
Replace only with part number
specified.
•Items marked “*” are not stocked since they
are seldom required for routine service. Some
delay should be anticipated when ordering
these items.
•The mechanical parts with no reference num-
ber in the exploded views are not supplied.
•Accessories and packing materials are given
in the last of the electrical parts list.
NOTE:
•-XX and -X mean standardized parts, so they
may have some difference from the original
one.
•Color Indication of Appearance Parts
Example:
KNOB, BALANCE (WHITE) . . . (RED)
↑↑
Parts ColorCabinet's Color
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
13-930-826-01BUTTON
23-930-823-21CABINET (UPPER)
33-930-827-01KNOB (FUNCTION)
41-535-804-11SNAP, BATTERY
*5A-3679-957-ARADIO BOARD, COMPLETE
63-922-610-01HOLDER (ANTENNA)
77-685-647-79SCREW +P 3X10 TYPE2 NON-SLIT
83-930-828-01KNOB (TUNING)
93-919-268-01KNOB (VOL)
10 3-930-829-01POINTER (INCLUDING rA: MARKER)
!11 1-769-339-22CORD, POWER (E)
!11 1-783-817-21CORD, POWER (US, Canadian)
12 3-930-824-01CABINET (LOWER)
13 7-685-154-19SCREW +P 3X35 TYPE2 NON-SLIT
14 3-368-852-01FOOT
15 3-369-135-21LID, BATTERY CASE
16 3-899-693-61PLATE, INDICATION
SP1 1-504-748-21SPEAKER (6.6CM)
!T101 1-427-927-11TRANSFORMER, POWER
not supplied
r A
SP1
T101
not supplied
(SECONDRY board)
not supplied
(PRIMARY board)
1
2
3
4
5
6
7
8
9
10
(including r A)
11
12
13
1415
16
11
E
US, Canadian
SECTION 7
ELECTRICAL PARTS LIST
Ref. No. Part No. Description Remark
NOTE:
•Due to standardization, replacements in the
parts list may be different from the parts speci-
fied in the diagrams or the components used
on the set.
•-XX and -X mean standardized parts, so they
may have some difference from the original
one.
•RESISTORS
All resistors are in ohms.
METAL: Metal-film resistor.
METAL OXIDE: Metal oxide-film resistor.
F: nonflammable
•Items marked “*” are not stocked since they
are seldom required for routine service.
Some delay should be anticipated when order-
ing these items.
•SEMICONDUCTORS
In each case, u: µ, for example:
uA. . : µA. . uPA. .: µPA. .
uPB. .: µPB. . uPC. .: µPC. .
uPD. .: µPD. .
•CAPACITORS
uF: µF
•COILS
uH: µH
Ref. No. Part No. Description Remark
RADIO
Les composants identifiés par une
marque !sont critiques pour la
sécurité.
Ne les remplacer que par une pièce
portant le neméro spécifié.
The components identified by
mark !or dotted line with mark
!are critical for safety.
Replace only with part number
specified.
When indicating parts by reference
number, please include the board.
*A-3679-957-ARADIO BOARD, COMPLETE
**********************
1-535-804-11SNAP, BATTERY
3-922-610-01HOLDER (ANTENNA)
< CAPACITOR >
C1 1-163-089-00CERAMIC CHIP 6PF 50V
C2 1-163-099-00CERAMIC CHIP 18PF 5% 50V
C3 1-163-713-11CERAMIC CHIP 27PF 5% 50V
C4 1-163-251-11CERAMIC CHIP 100PF 5% 50V
C5 1-163-031-11CERAMIC CHIP 0.01uF 50V
C6 1-126-964-11ELECT 10uF 20% 50V
C7 1-163-031-11CERAMIC CHIP 0.01uF 50V
C8 1-126-963-11ELECT 4.7uF 20% 50V
C9 1-126-963-11ELECT 4.7uF 20% 50V
C10 1-126-964-11ELECT 10uF 20% 50V
C11 1-163-033-00CERAMIC CHIP 0.022uF 50V
C12 1-163-809-11CERAMIC 0.047uF 10% 25V
C13 1-128-551-11ELECT 22uF 20% 25V
C14 1-163-038-00CERAMIC CHIP 0.1uF 25V
C15 1-126-924-11ELECT 330uF 20% 10V
C16 1-164-004-11CERAMIC CHIP 0.1uF 10% 25V
C18 1-126-924-11ELECT 330uF 20% 10V
C19 1-163-031-11CERAMIC CHIP 0.01uF 50V
C20 1-163-222-11CERAMIC CHIP 5PF 0.25PF50V
C101 1-163-019-00CERAMIC CHIP 0.0068uF10% 50V
C102 1-164-232-11CERAMIC CHIP 0.01uF 50V
C103 1-163-031-11CERAMIC CHIP 0.01uF 50V
C104 1-163-038-00CERAMIC CHIP 0.1uF 25V
C107 1-126-963-11ELECT 4.7uF 20% 50V
C201 1-163-031-11CERAMIC CHIP 0.01uF 50V
C202 1-163-031-11CERAMIC CHIP 0.01uF 50V
C203 1-126-934-11ELECT 220uF 20% 16V
C204 1-163-031-11CERAMIC CHIP 0.01uF 50V
C205 1-163-031-11CERAMIC CHIP 0.01uF 50V
C206 1-126-925-11ELECT 470uF 20% 10V
C207 1-126-933-11ELECT 100uF 20% 10V
< FILTER >
CF1 1-577-324-81FILTER, CERAMIC
CF2 1-577-072-11FILTER, CERAMIC
CF3 1-577-324-81FILTER, CERAMIC
< CONNECTOR >
*CN701 1-568-272-11SOCKET, CONNECTOR 6P
< VARIABLE CAPACITOR >
CT1-4 1-141-529-11CAP, VARIABLE
CV1 1-141-529-11CAP, VARIABLE (TUNING)
< DIODE >
D101 8-719-911-19DIODE 1SS119
D201 8-719-911-19DIODE 1SS119
D202 8-719-052-88DIODE 1N4002
D203 8-719-911-19DIODE 1SS119
D204 8-719-911-19DIODE 1SS119
D205 8-719-911-19DIODE 1SS119
< IC >
IC1 8-752-055-05IC CXA1019S
IC101 8-759-821-46IC LM8560N
< JUMPER RESISTOR >
JC1 1-216-295-00CONDUCTOR CHIP (2012)
< COIL >
L1 1-501-765-11ANTENNA, FERRITE-ROD (AM)
L2 1-406-028-00COIL, OSC (MW)
L4 1-428-222-11COIL, AIR-CORE
< LED >
LED1011-801-083-11LED OHC-603HA
< TRANSISTOR >
Q1 8-729-119-76TRANSISTOR 2SA1175-HFE
Q201 8-729-011-92TRANSISTOR 2SC2001TP-K1K2
Q202 8-729-119-76TRANSISTOR 2SA1175-HFE
< RESISTOR >
R2 1-216-017-00METAL GLAZE 47 5% 1/10W
R4 1-216-057-00METAL CHIP 2.2K 5% 1/10W

– 13 –
Ref. No. Part No. Description Remark
R5 1-216-057-00METAL CHIP 2.2K 5% 1/10W
R101 1-216-105-00METAL GLAZE 220K 5% 1/10W
R102 1-216-097-00METAL GLAZE 100K 5% 1/10W
R103 1-216-097-00METAL GLAZE 100K 5% 1/10W
R104 1-216-089-00METAL GLAZE 47K 5% 1/10W
R105 1-216-081-00METAL CHIP 22K 5% 1/10W
R204 1-216-009-00METAL CHIP 22 5% 1/10W
R205 1-216-041-00METAL GLAZE 470 5% 1/10W
< VARIABLE RESISTOR >
RV1 1-228-790-00RES, VAR, CARBON 50K (VOLUME)
< SWITCH >
S1 1-692-181-21SWITCH, SLIDE (FM/AM)
S2 1-762-232-11SWITCH, SLIDE
(OFF/RADIO ON/RADIO/BUZZER)
S3 1-554-303-21SWITCH, TACTILE (TIME SET M)
S4 1-554-303-21SWITCH, TACTILE (TIME SET H)
S5 1-554-303-21SWITCH, TACTILE (ALARM)
S6 1-554-303-21SWITCH, TACTILE (CLOCK)
S7 1-554-303-21SWITCH, TACTILE (SLEEP)
S8 1-554-303-21SWITCH, TACTILE (SNOOZE/SLEEP OFF)
< TRANSFORMER >
T1 1-404-790-11TRANSFORMER, IF
< FLAT CABLE >
*W701 1-776-983-11CORD, CONNECTION
*W702 1-769-137-11CORD, CONNECTION (16 CORE)
************************************************************
MISCELLANEOUS
***************
!11 1-769-339-22CORD, POWER (E)
!11 1-783-817-21CORD, POWER (US, Canadian)
SP1 1-504-748-21SPEAKER (6.6CM)
!T101 1-427-927-11TRANSFORMER, POWER
************************************************************
ACCESSORIES & PACKING MATERIALS
********************************
3-862-233-12MANUAL, INSTRUCTION
(ENGLISH, FRENCH, SPANISH, PORTUGUESE)
(EXCEPT US)
3-862-233-21MANUAL, INSTRUCTION (ENGLISH) (US)
RADIO
The components identified by
mark !or dotted line with
mark !are critical for safety.
Replace only with part num-
ber specified.
Les composants identifiés par une
marque !sont critiques pour la
sécurité.
Ne les remplacer que par une pièce
portant le neméro spécifié.

– 14 –
ICF-C121
Sony Corporation
Personal & Mobile Communication Company9-925-799-11 98B0531-1
Printed in Japan © 1998. 2
Published by Quality Assurance Dept.

SERVICE MANUAL
4
56
7
4
5
6
7
ICF-C121
SUPPLEMENT-1
File this supplement with the service manual.
US Model
Canadian Model
E Model
Subject:
1. Addition of Black Model (Canadian Model)
2. Correction
1. ADDITION OF BLACK MODEL (Canadian Model)
(ENG-99004)
Page Before change After change
Ref. No. Part No. Description Remark
1 3-930-826-01 BUTTON (for WHITE)
1 3-930-826-11 BUTTON (for BLACK) (Canadian)
2 3-930-823-21 CABINET (UPPER) (WHITE)
2 3-930-823-31 CABINET (UPPER) (BLACK) (Canadian)
3 3-930-827-01 KNOB (FUNCTION) (for WHITE)
3 3-930-827-11 KNOB (FUNCTION) (for BLACK) (Canadian)
12 3-930-824-01 CABINET (LOWER) (WHITE)
12 3-930-824-13 CABINET (LOWER) (BLACK) (Canadian)
Ref. No. Part No. Description Remark
11
1 3-930-826-01 BUTTON
2 3-930-823-21 CABINET (UPPER)
3 3-930-827-01 KNOB (FUNCTION)
12 3-930-824-01 CABINET (LOWER)
2. CORRECTION
EXPLODED VIEW
!: Indicates corrected portion.
Page INCORRECT CORRECT
11
Ref. No. Part No. Description Remark
*5 A-3679-957-A RADIO BOARD, COMPLETE
Ref. No. Part No. Description Remark
*5 A-3679-957-A RADIO BOARD, COMPLETE
@
@
• Items marked “*” are not stocked since they are seldom required for routine service.
Some delay should be anticipated when ordering these items. Continued on page 2.
1999. 06

– 2 –
T101
not supplied
(SECONDRY board)
not supplied
(PRIMARY board)
11
T101
not supplied
(SECONDRY board)
not supplied
(PRIMARY board)
11
12
13 11
E
US, Canadian
MISCELLANEOUS
**************
!11 1-769-339-22 CORD, POWER (E)
!11 1-783-817-21 CORD, POWER (US, Canadian)
*******************************************************
ACCESSORIES & PACKING MATERIALS
********************************
3-862-233-12 MANUAL, INSTRUCTION (ENGLISH,
FRENCH, SPANISH, PORTUGUESE)
(EXCEPT US)
!11 1-769-339-22 CORD, POWER (E)
!11 1-783-817-21 CORD, POWER (US, Canadian)
Page INCORRECT CORRECT
11
!: Indicates corrected portion.
Sony Corporation
Personal Audio Company
9-925-799-81 99F05042-1D
Printed in Japan © 1999. 6
Published by General Engineering Dept.
Ref. No. Part No. Description RemarkRef. No. Part No. Description Remark
!11 1-769-339-22 CORD, POWER
@
@
@
@
ELECTRICAL PARTS LIST
!: Indicates corrected portion.
Page INCORRECT CORRECT
Ref. No. Part No. Description Remark
Ref. No. Part No. Description Remark
13
MISCELLANEOUS
**************
4 1-535-804-11 SNAP, BATTERY
!11 1-769-339-22 CORD, POWER
*******************************************************
ACCESSORIES & PACKING MATERIALS
********************************
3-862-233-11 MANUAL, INSTRUCTION (ENGLISH,
FRENCH, SPANISH, PORTUGUESE)
(EXCEPT US)
@
@
@
#
The components identified by
mark !or dotted line with
mark !are critical for safety.
Replaceonly withpart number
specified.
Les composants identifiés par une
marque !sont critiques pour la
sécurité.
Ne les remplacer que par une pièce
portant le numéro spécifié.

SERVICE MANUAL
ICF-C121
SUPPLEMENT-2
File this supplement with the service manual.
Subject:Addition of Parts (US model only)
(Serial No. 1,544,651 and later)
(ECN-801622)
US Model
Canadian Model
E Model
FormerType NewType
•DISCRIMINATION
– Specification Label –
LABEL FCC (RADIO)
1999.11

– 2 –
• PRINTED WIRING BOARD
!: Changed portion.
Page Former Type NewType
7
Location C-G, 1-3
$
• View A
SHIELD
CASE
Bond
SOLDER L2
S1
b
View A
$

– 3 –
• SCHEMATIC DIAGRAM
!: Changed portion.
Page FormerType NewType
9
Location C-G, 5-8
^
^

– 4 –
• EXPLODED VIEW
Page Before Change After Change
Ref. No. Part No. Description Remark
*5 A-3679-957-A RADIO BOARD, COMPLETE (EXCEPT US)
*5 A-3683-137-A RADIO BOARD, COMPLETE (US)
Ref. No. Part No. Description Remark
*5 A-3679-957-A RADIO BOARD, COMPLETE
11
Sony Corporation
Personal Audio Division Company
9-925-799-82 99K0516-1
Printed in Japan C1999. 11
Published by General Engineering Dept.
• ELECTRICAL PARTS LIST
*A-3679-957-A RADIO BOARD, COMPLETE *A-3679-957-A RADIO BOARD, COMPLETE (EXCEPT US)
*A-3683-137-A RADIO BOARD, COMPLETE (US)
C30 1-162-282-31 CERAMIC 100PF 10% 50V (US)
C31 1-162-600-11 CERAMIC 0.0047uF 20% 16V (US)
Page Former Type NewType
Ref. No. Part No. Description RemarkRef. No. Part No. Description Remark
12
ICF-C121
• Items marked “*” are not stocked since they are seldom required for routine service.
Some delay should be anticipated when ordering these items.