Sony DREAM MACHINE ICF-C793 User manual

MICROFILM
SERVICE MANUAL
ICF-C793
FM/AM PLL SYNTHESIZED CLOCK RADIO
ICF-C793L
FM/MW/LW PLL SYNTHESIZED CLOCK RADIO
US Model
Canadian Model
Australian Model
ICF-C793
AEP Model
ICF-C793/C793L
UK Model
ICF-C793L
SPECIFICATIONS
ICF-C793/C793L
Photo: ICF-C793L
Ver 1.0 1999. 02

– 2 –
TABLE OF CONTENTS
1. GENERAL ................................................................... 3
2. DISASSEMBLY ......................................................... 5
3. ELECTRICAL ADJUSTMENTS......................... 6
4. DIAGRAMS
4-1. Block Diagram ................................................................ 9
4-2. Printed Wiring Boards .................................................... 11
4-3. Schematic Diagram ......................................................... 13
4-4. IC Pin Function Description ........................................... 16
5. EXPLODED VIEWS................................................ 17
6. ELECTRICAL PARTS LIST ............................... 19
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.
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.
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 2V AC 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
CF
2
CF3
mark
Mark Center frequency
red 10.70 MHz
blue 10.67 MHz
orange 10.73 MHz
black 10.64 MHz
white 10.76 MHz
HOW TO CHANGED THE CERAMIC FILTERS
This model is used two ceramic filters of CF2 and CF3.
You must used same type of color marked ceramic filters in order
to meet same specifications.
Therefore, the ceramic filter must changed two pieces together
since it’s supply two pieces in one package as a spare parts.

– 3 –
SECTION 1
GENERAL This section is extracted from
instruction manual.
LOCATION OF CONTROLS

– 4 –

– 5 –
CHASSIS ASS’Y
POWER CORD SETTING
Note: Follow the disassembly procedure in the numerical order given.
SECTION 2
DISASSEMBLY
1 screw (P3 × 14)
2 three claws
2 claw
6 button (DST)
5 Break the soldering of
speaker lead.
7 chassis assy
3 rear cabinet
6 knob (brightness)
1 four screws (P3 × 14
)
4 connector
(CN301)
rear cabine
t
power cord
boss
rear cabinet
power cord
Put the secondary flat cable
between bosses to fix.
Set the power cord as illustrated below,
then install the cabinet.

– 6 –
FM VCO VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L4 87.5 MHz 3 V ± 0.1V
Confirmation 108 MHz Less than 11.8 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L3 87.5 MHz
TC3 108 MHz
AM (MW) VCO VOLTAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L5 530 kHz (531kHz *1) 2.65 V ± 0.1V
Confirmation 1,710 kHz Less than 10 V (9.5V *1)
(1,602 kHz *1)
AM (MW) TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter.
L1 (L1-1 *2) 580 kHz (621 kHz *1)
TC1 1,490 kHz (1,404 kHz *1)
LW VCO VOLTAGE ADJUSTMENT *2
Adjustment Part Frequency Display Reading on Digital Voltmeter
TC4 153 kHz 2.25 V ± 0.05V
Confirmation 279 kHz Less than 9.5 V
LW TRACKING ADJUSTMENT *2
Adjust for a maximum reading on level meter.
L1-2 162 kHz
TC2 243 kHz
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
T1 450 kHz
*1) Except US, Canadian models
*2) -ICF-C793L
SECTION 3
ELECTRICAL ADJUSTMENTS
0 dB = 1 µV
[FM]
Setting:
Band switch: FM
[AM (MW/LW)*]
*AM : ICF-C793
MW/LW: ICF-C793L
Setting:
Band switch: AM (MW/LW)
• Repeat the procedures in each adjustment several times, and the
frequency coverage and tracking adjustments should be finally
done by the trimmer capacitors.
• Remove FM antenna in FM adjustments.
Adjustment Location: Main Board (See page 7)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
+
–
level meter
MAIN board TP (SP GND)
MAIN board
TP (SP +)
set
FM antenna in
8 Ω
0.01 µ F
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
Put the lead-wire
antenna close to
the set.
+
–
level meter
set
8 Ω
MAIN board TP (SP GND)
MAIN board
TP (SP +)
+
–
digital voltmete
r
MAIN board
TP (VT)

– 7 –
TC2 L1-2 L1 (L1-1 * )
AM (MW) Tracking Adjustment
LW Tracking Adjustment
*
L3 TC3
FM Tracking Adjustment
T1 AM IF
TC1 AM (MW) Tracking Adjustment
L4 FM VCO Voltage Adjustment
L5 AM (MW) VCO Voltage Adjustment
TC4 LW VCO Voltage Adjustment *
TP (VT) TP (SP+)
TP (SP GND)
TP (FM-IN)
– MAIN BOARD (Component Side) – – MAIN BOARD (Conductor Side) –
Adjustment Location:
*) ICF-C793L

ICF-C793/C793L
– 9 – – 10 –
SECTION 4
DIAGRAMS
4-1. BLOCK DIAGRAM
12
9
14 17
10
5 7
FM
FRONT-END FM
IF AMP AF POWER AMP
AM IF AMP,
AGC, DET
AM
FRONT-END 16
19
FM RF
IN FM/AM
FE OUT CF2
10.7MHz
CF1
450kHz
CF3
10.7MHz
FM
RF FM
IF IN
2FM
DISCRIMINATOR
TUNING METER
FM
DISCRI
27
AF
OUT SP301
(SPEAKER)
AF
IN
23 24
DET
OUT
AM
IF IN
METER
NF VOL
15
1
2
3 4
FM/AM
BAND
SELECT
AM OSC
L5
AM (MW/LW)
OSC
L4
FM OSC
X50
75kHz
L1
AM (MW/LW)
FERRITE-ROD
ANTENNA
ANT1
FM LEAD
ANTENNA
FM OSC
AM RF
IN
L3
FM RF
FM/AM FRONT-END,
FM/AM IF AMP, DET, AGC, AF AMP
IC1
FM/AM PLL
IC50
SYSTEM CONTROLLER,
LCD DRIVER, KEY CONTROL
IC100
TC1 D4-1
D1-1
(C793) (C793L)
L1-1
(MW)
L1-2
(LW)
Q1
MW/LW
SWITCH
Q3
MW/LW
SWITCH
B+
B+
Q52
MW/LW
SWITCH
CONTROL
(C793)
(C793L)
(C793L) TC4
TC3
VR1
VOL
+
+
L4
FM VCO VOLTAGE
D74
A RADIO D75
B BUZZER S50
BRIGHTNESS
(LCD BACK LIGHT)
D70 – 73
(LCD BACK LIGHT)
D74 D75 –2
–1
L5
AM (MW) VCO VOLTAGE
TC4
LW VCO
VOLTAGE
L1, TC1
AM TRACKING
L3, TC3
FM TRACKING
T1
AM IF
B.P.F.
BPF1
LOW-PASS FILTER
Q50, 51
LED DRIVE
Q53, 54
MUTING
Q4
• SIGNAL PATH
: FM
: AM (MW/LW)
05
D1-2
D2
D3
AC IN
BACKUP B+
(SYSTEM CONTROLLER IC100 B+)
B+
BZ-CTRL
35
ALM A
6
ALM B
7
BUZZER
36
DATA DA
PD1
27
5
15
CLK CK
26
4
CE CE
34
3
MUTE
PDET
33
28
RESET
18
AM IN
11
FM IN
XOUT
XIN
22 23
X101
4.19MHz
X1 X2
19 20
X100
32.768kHz
XT1 XT2 S0 – S23
12
P0 P1
78
D100
D101
VT B+
RECT
D351 – 354
REGULATOR
Q57
T301
POWER
TRANSFORMER
RECT
D355
RESET SIGNAL
GENERATOR
IC101
COM0 – COM3
S101, 201 – 218
(KEY MATRIX)
60 – 37 61 – 64
KS0 – KS4
10 – 13, 8
KR0 – KR3
14 – 17
LIQUID CRYSTAL DISPLAY
LCD100
L1-1, TC1
MW TRACKING
L1-2, TC2
LW TRACKING
TC2
Q5
TONE
CONTROL
SWITCH
D4-2
D1-3
(C793)
(C793L)
(C793L)
(C793L)
(C793L)
D102
D60, 61
HIGH
LOW

ICF-C793/C793L
– 13 – – 14 – – 15 –
4-3. SCHEMATIC DIAGRAM
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 and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
no mark : FM
( ) : AM (MW/LW)
• Voltagesare takenwith aVOM(Inputimpedance 10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: AM (MW/LW)
• Abbreviation
AUS : Australian model
CND : Canadian model
FR : French model
Note:
The components identi-
fied by mark !or dotted
linewith mark !are criti-
cal for safety.
Replace only with part
number specified.
Note:
Lescomposants identifiés par
une marque !sont critiques
pour la sécurité.
Ne les remplacer que par une
piéce portant le numéro
spécifié.
• Waveforms
– MAIN BOARD –
1IC50 2(X IN)
1 V/DIV, 10 µs/DIV 3IC100 @™ (X1)
1 V/DIV, 500 ms/DIV
• IC Block Diagrams
– MAIN BOARD –
IC1 CXA1019M
IC50 BU2614FS
FM FE
TUNING METER
AM IF DET AGC
AF POWER AMP
FM IF
FM/AM IF OUT FM RF IN FE GND
NC
AM RF IN FM RF FM OSC REG OUT AFC AM OSC NF VOL FM DISCRI GND
FM/AM BAND
SELECT
FM IF IN
AM IF IN
NC
METER
IF GND
DET OUT
AFC AGC
AFC AGC
AF IN
RIPPLE FILTER
AF OUT
VCC
GND
AM FE
FM
DISCRIMINATOR
14 13 12 11 10 9 8 7 2 16 5 34
15 16 17 18 19 20 21 22 23 24 25 26 27 28
FM IN PD1 VSS VDD2 VDD1
AM IN
P2 IF-IN
XOUT
XIN
CE
CK
DA CD
P0 P1
16 12131415
8
9
10
11
4561 2 3 7
IF
COUNTER
OUTPUT
CONTROL
I/O CONTROL
REGISTER
MAIN CONTROL
PRESCALLER
PHASE
DETECT
1.9 Vp-p
13.3 µ s
2 Vp-p
238.7 ns
2IC100 !ª (XT1)
1 V/DIV, 20 µs/DIV
2 Vp-p
30.5 µ s
Note:
• Press either [+] or [–] key when RADIO is being
operated, oscillation will be given out for 250 ms.
• Oscillation will be given out for 250 ms when the
power is turned on.

– 19 –
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
*1-671-841-11 ALARM KEY BOARD
****************
<SWITCH>
S201 1-553-856-00 SWITCH, KEYBOARD (-, ALARM TIME)
S202 1-553-856-00 SWITCH, KEYBOARD (+, ALARM TIME)
S203 1-553-856-00 SWITCH, KEYBOARD (B, ON/OFF)
S204 1-553-856-00 SWITCH, KEYBOARD (-, ALARM TIME)
S205 1-553-856-00 SWITCH, KEYBOARD (+, ALARM TIME)
S206 1-553-856-00 SWITCH, KEYBOARD (A, ON/OFF)
*************************************************************
A-3663-208-A MAIN BOARD, COMPLETE (C793: US, CND)
A-3663-266-A MAIN BOARD, COMPLETE (C793: AUS)
A-3663-268-A MAIN BOARD, COMPLETE (C793: AEP)
A-3663-272-A MAIN BOARD, COMPLETE (C793L: FR)
A-3663-275-A MAIN BOARD, COMPLETE (C793L: UK)
*********************
3-032-464-01 HOLDER (LCD)
<ANTENNA>
ANT1 1-501-907-21 ANTENNA, FM WIRE (FM LEAD ANTENNA)
<BAND PASS FILTER>
BPF1 1-236-711-21 FILTER, BAND PASS
<CAPACITOR>
C1 1-163-253-11 CERAMIC CHIP 120PF 5% 50V
(C793L)
C6 1-163-251-11 CERAMIC CHIP 100PF 5% 50V
C7 1-163-141-00 CERAMIC CHIP 0.001uF 5% 50V
C8 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C9 1-163-224-11 CERAMIC CHIP 7PF 0.25PF 50V
C11 1-163-141-00 CERAMIC CHIP 0.001uF 5% 50V
C12 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
(C793L)
C15 1-163-251-11 CERAMIC CHIP 100PF 5% 50V
(C793: US, CND)
C16 1-163-251-11 CERAMIC CHIP 100PF 5% 50V
(C793: US, CND)
C17 1-163-251-11 CERAMIC CHIP 100PF 5% 50V
(C793: US, CND)
C20 1-163-059-91 CERAMIC CHIP 0.01uF 10% 50V
C21 1-126-963-11 ELECT 4.7uF 20% 50V
C22 1-126-964-11 ELECT 10uF 20% 50V
C23 1-163-063-00 CERAMIC CHIP 0.022uF 10% 50V
C24 1-164-004-11 CERAMIC CHIP 0.1uF 10% 25V
C25 1-163-989-11 CERAMIC CHIP 0.033uF 10% 25V
(C793L)
C26 1-126-964-11 ELECT 10uF 20% 50V
C27 1-163-085-00 CERAMIC CHIP 2PF 50V
C28 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C29 1-163-227-11 CERAMIC CHIP 10PF 0.5PF 50V
(C793)
C29 1-163-229-11 CERAMIC CHIP 12PF 5% 50V
(C793L)
C30 1-126-960-11 ELECT 1uF 20% 50V
C31 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C32 1-163-132-00 CERAMIC CHIP 430PF 5% 50V
C33 1-163-989-11 CERAMIC CHIP 0.033uF 10% 25V
C34 1-163-227-11 CERAMIC CHIP 10PF 0.5PF 50V
(C793L)
C41 1-126-934-11 ELECT 220uF 20% 10V
C42 1-128-551-11 ELECT 22uF 20% 25V
C43 1-109-982-11 CERAMIC CHIP 1uF 10% 10V
C44 1-109-982-11 CERAMIC CHIP 1uF 10% 10V
C45 1-126-934-11 ELECT 220uF 20% 10V
C46 1-163-263-11 CERAMIC CHIP 330PF 5% 50V
(C793L)
C47 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C48 1-163-077-00 CERAMIC CHIP 0.1uF 10% 25V
C50 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C51 1-163-009-11 CERAMIC CHIP 0.001uF 10% 50V
C53 1-110-501-11 CERAMIC CHIP 0.33uF 10% 16V
C54 1-163-125-00 CERAMIC CHIP 220PF 5% 50V
C55 1-104-664-11 ELECT 47uF 20% 10V
C56 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
(C793L)
C57 1-115-340-11 CERAMIC CHIP 0.22uF 10% 16V
C59 1-163-231-11 CERAMIC CHIP 15PF 5% 50V
C60 1-163-231-11 CERAMIC CHIP 15PF 5% 50V
C62 1-126-934-11 ELECT 220uF 20% 10V
C63 1-163-125-00 CERAMIC CHIP 220PF 5% 50V
C66 1-164-489-11 CERAMIC CHIP 0.22uF 10% 16V
C100 1-163-038-00 CERAMIC CHIP 0.1uF 25V
C101 1-163-038-00 CERAMIC CHIP 0.1uF 25V
C103 1-164-004-11 CERAMIC CHIP 0.1uF 10% 25V
C104 1-125-691-11 DOUBLE LAYER 0.022F 5.5V
SECTION 6
ELECTRICAL PARTS LIST
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
Les composants identifiés par une
marque !sont critiquens pour la
sécurité.
Ne les remplacer que par une pièce
portant le numéro 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.
• Abbreviation
AUS : Australian model
CND: Canadian model
FR : French model
ALARM KEY MAIN

– 20 –
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
C107 1-163-235-11 CERAMIC CHIP 22PF 5% 50V
C108 1-163-235-11 CERAMIC CHIP 22PF 5% 50V
C110 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C111 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C113 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
C114 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
C115 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
C116 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
C117 1-163-133-00 CERAMIC CHIP 470PF 5% 50V
C118 1-163-009-11 CERAMIC CHIP 0.001uF 10% 50V
C121 1-163-038-00 CERAMIC CHIP 0.1uF 25V
C351 1-126-927-11 ELECT 2200uF 20% 10V
C352 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C353 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C354 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C355 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C356 1-163-021-11 CERAMIC CHIP 0.01uF 10% 50V
C357 1-104-666-11 ELECT 220uF 20% 25V
<FILTER>
*CF1 1-577-319-11 FILTER, CERAMIC (450kHz) (C793)
CF1 1-578-677-21 FILTER, CRYSTAL (450kHz) (C793L)
CF2 1-579-632-41 FILTER, CERAMIC (10.7MHz)
CF3 1-579-632-41 FILTER, CERAMIC (10.7MHz)
<CONNECTOR>
*CN704 1-568-271-11 SOCKET, CONNECTOR 5P
<DIODE>
D1 8-719-057-59 DIODE SVC354S-TR (C793L)
D2 8-713-100-11 DIODE 1T362
D3 8-713-100-11 DIODE 1T362
D4 8-719-072-59 DIODE SVC347S-TL (C793)
D7 8-719-074-44 DIODE 1SS120RX (C793: US, CND)
D8 8-719-074-44 DIODE 1SS120RX (C793: US, CND)
D50 8-719-976-99 DIODE DTZ5.1B
D60 8-719-988-61 DIODE 1SS355TE-17
D61 8-719-988-61 DIODE 1SS355TE-17
D70 8-719-950-41 LED GL-3EG43 (LCD BACK LIGHT)
D71 8-719-950-41 LED GL-3EG43 (LCD BACK LIGHT)
D72 8-719-950-41 LED GL-3EG43 (LCD BACK LIGHT)
D73 8-719-950-41 LED GL-3EG43 (LCD BACK LIGHT)
D74 8-719-073-99 LED TLYE262(NP.TPK51)
(A RADIO, LCD BACK LIGHT)
D75 8-719-073-99 LED TLYE262(NP.TPK51)
(B BUZZER, LCD BACK LIGHT)
D100 8-719-074-44 DIODE 1SS120RX
D101 8-719-988-61 DIODE 1SS355TE-17
D102 8-719-988-61 DIODE 1SS355TE-17
D351 8-719-031-85 DIODE 1N4002L
D352 8-719-031-85 DIODE 1N4002L
D353 8-719-031-85 DIODE 1N4002L
D354 8-719-031-85 DIODE 1N4002L
D355 8-719-074-44 DIODE 1SS120RX
<IC>
IC1 8-752-050-16 IC CXA1019M
IC50 8-759-188-85 IC BU2614FS
IC100 8-759-571-48 IC uPD753106GC-053-AB8
IC101 8-759-580-04 IC S-80820ALUP-EAH-T2
<SHORT>
JC1 1-216-296-00 SHORT 0
JC2 1-216-296-00 SHORT 0
JC3 1-216-296-00 SHORT 0
JC4 1-216-296-00 SHORT 0
JC5 1-216-296-00 SHORT 0
JC6 1-216-296-00 SHORT 0
JC8 1-216-295-00 SHORT 0
JC9 1-216-296-00 SHORT 0
JC10 1-216-296-00 SHORT 0
JC11 1-216-296-00 SHORT 0
JC12 1-216-296-00 SHORT 0
JC13 1-216-296-00 SHORT 0
JC14 1-216-296-00 SHORT 0
JC15 1-216-296-00 SHORT 0
JC18 1-216-296-00 SHORT 0
JC19 1-216-296-00 SHORT 0
JC20 1-216-296-00 SHORT 0
JC21 1-216-296-00 SHORT 0
JC22 1-216-296-00 SHORT 0
JC23 1-216-295-00 SHORT 0 (C793L)
JC24 1-216-296-00 SHORT 0
JC61 1-216-296-00 SHORT 0 (C793: US, CND)
JC62 1-216-296-00 SHORT 0 (C793: US, CND)
JC63 1-216-296-00 SHORT 0
JC99 1-216-295-00 SHORT 0
JC128 1-216-295-00 SHORT 0 (C793: AUS/C793L: FR)
JC129 1-216-295-00 SHORT 0 (C793: AEP/C793L: FR)
JC130 1-216-295-00 SHORT 0 (C793L: UK)
JC135 1-216-296-00 SHORT 0
JC136 1-216-296-00 SHORT 0
JC137 1-216-296-00 SHORT 0
JC138 1-216-296-00 SHORT 0
JC142 1-216-296-00 SHORT 0
JC143 1-216-296-00 SHORT 0
JC144 1-216-296-00 SHORT 0
JC145 1-216-296-00 SHORT 0
JC146 1-216-296-00 SHORT 0
JC147 1-216-295-00 SHORT 0
JC148 1-216-296-00 SHORT 0
JC149 1-216-296-00 SHORT 0
JC150 1-216-296-00 SHORT 0
JC151 1-216-296-00 SHORT 0
JC152 1-216-296-00 SHORT 0
JC153 1-216-296-00 SHORT 0
JC301 1-216-295-00 SHORT 0 (C793: US, CND)
<COIL>
L3 1-406-545-11 COIL, AIR-CORE
L4 1-406-545-11 COIL, AIR-CORE
L5 1-406-485-11 COIL (OSC)
<LIQUID CRYSTAL DISPLAY>
LCD100 1-803-446-11 DISPLAY PANEL, LIQUID CRYSTAL
MAIN

– 21 –
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
<IC LINK>
PS301 1-533-588-11 LINK, IC (C793: AEP, AUS/C793L)
<TRANSISTOR>
Q1 8-729-102-07 TRANSISTOR 2SC2223-F13 (C793L)
Q3 8-729-102-07 TRANSISTOR 2SC2223-F13 (C793L)
Q4 8-729-216-22 TRANSISTOR 2SA1162-G
Q5 8-729-120-28 TRANSISTOR 2SC1623-L5L6 (C793L)
Q50 8-729-120-28 TRANSISTOR 2SC1623-L5L6
Q51 8-729-120-28 TRANSISTOR 2SC1623-L5L6
Q52 8-729-216-22 TRANSISTOR 2SA1162-G (C793L)
Q53 8-729-120-28 TRANSISTOR 2SC1623-L5L6
Q54 8-729-120-28 TRANSISTOR 2SC1623-L5L6
Q57 8-729-840-00 TRANSISTOR 2SD400-E
<RESISTOR>
R1 1-216-133-00 METAL CHIP 3.3M 5% 1/10W
(C793L)
R2 1-216-073-00 RES, CHIP 10K 5% 1/10W
(C793L)
R3 1-216-097-00 RES, CHIP 100K 5% 1/10W
R4 1-216-057-00 METAL CHIP 2.2K 5% 1/10W
R5 1-216-037-00 METAL CHIP 330 5% 1/10W
R6 1-216-049-11 RES, CHIP 1K 5% 1/10W
R7 1-216-081-00 METAL CHIP 22K 5% 1/10W
(C793L)
R8 1-216-097-00 RES, CHIP 100K 5% 1/10W
R9 1-216-121-00 RES, CHIP 1M 5% 1/10W
R10 1-216-073-00 METAL CHIP 10K 5% 1/10W
R11 1-216-017-00 RES, CHIP 47 5% 1/10W
R12 1-216-061-00 METAL CHIP 3.3K 5% 1/10W
(C793: US, CND)
R12 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
(C793: AEP, AUS/C793L)
R13 1-216-057-00 METAL CHIP 2.2K 5% 1/10W
(C793L)
R14 1-216-071-00 METAL CHIP 8.2K 5% 1/10W
R15 1-216-198-00 RES, CHIP 1K 5% 1/8W
R16 1-216-073-00 METAL CHIP 10K 5% 1/10W
R18 1-216-097-00 RES, CHIP 100K 5% 1/10W
R48 1-216-033-00 METAL CHIP 220 5% 1/10W
R49 1-216-049-11 RES, CHIP 1K 5% 1/10W
R50 1-216-073-00 METAL CHIP 10K 5% 1/10W
R51 1-216-097-00 RES, CHIP 100K 5% 1/10W
R52 1-216-073-00 METAL CHIP 10K 5% 1/10W
R54 1-216-073-00 METAL CHIP 10K 5% 1/10W
R56 1-216-166-00 RES, CHIP 47 5% 1/8W
R57 1-216-198-00 RES, CHIP 1K 5% 1/8W
R58 1-216-198-00 RES, CHIP 1K 5% 1/8W
R59 1-216-198-00 RES, CHIP 1K 5% 1/8W
R61 1-216-017-00 RES, CHIP 47 5% 1/10W
R62 1-216-029-00 METAL CHIP 150 5% 1/10W
R63 1-216-029-00 METAL CHIP 150 5% 1/10W
R64 1-216-029-00 METAL CHIP 150 5% 1/10W
R65 1-216-029-00 METAL CHIP 150 5% 1/10W
R66 1-216-182-00 RES, CHIP 220 5% 1/8W
R67 1-216-182-00 RES, CHIP 220 5% 1/8W
R69 1-216-041-00 METAL CHIP 470 5% 1/10W
R75 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
(C793L)
R133 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R134 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R135 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R136 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R137 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R138 1-216-097-00 RES, CHIP 100K 5% 1/10W
R139 1-216-109-00 METAL CHIP 330K 5% 1/10W
R140 1-216-214-00 RES, CHIP 4.7K 5% 1/8W
R141 1-216-214-00 RES, CHIP 4.7K 5% 1/8W
R142 1-216-065-00 RES, CHIP 4.7K 5% 1/10W
R143 1-216-246-00 RES, CHIP 100K 5% 1/8W
R144 1-216-001-00 METAL CHIP 10 5% 1/10W
R145 1-216-081-00 METAL CHIP 22K 5% 1/10W
R146 1-216-073-00 METAL CHIP 10K 5% 1/10W
R147 1-216-057-00 METAL CHIP 2.2K 5% 1/10W
R148 1-216-073-00 METAL CHIP 10K 5% 1/10W
R149 1-216-222-95 RES, CHIP 10K 10% 1/8W
R351 1-216-198-00 RES, CHIP 1K 5% 1/8W
<SWITCH>
S50 1-571-478-11 SWITCH, SLIDE (BRIGHTNESS)
S101 1-554-088-00 SWITCH, KEY BOARD (D. S. T./SUMMER T. )
<TRANSFORMER>
T1 1-404-790-11 TRANSFORMER, IF
<VARIABLE CAPACITOR>
TC1 1-141-601-21 CAP, ADJ 10PF
TC2 1-141-605-21 CAP, ADJ 40PF (C793L)
TC3 1-141-601-21 CAP, ADJ 10PF
TC4 1-141-605-21 CAP, ADJ 40PF (C793L)
<VARIABLE RESISTOR>
VR1 1-228-790-00 RES, VAR, CARBON 50K (VOL)
<VIBRATOR>
X50 1-767-517-11 VIBRATOR, CRYSTAL (75kHz)
X100 1-567-098-41 VIBRATOR, CRYSTAL (32.768kHz)
X101 1-760-641-21 VIBRATOR, CERAMIC (4.19MHz)
************************************************************
*1-671-840-11 MAIN KEY BOARD
***************
<SWITCH>
S207 1-553-856-00 SWITCH, KEYBOARD (1, WAKE UP STATION)
S208 1-553-856-00 SWITCH, KEYBOARD
(ALARM RESET, RADIO OFF)
S209 1-553-856-00 SWITCH, KEYBOARD (BAND)
S210 1-553-856-00 SWITCH, KEYBOARD (5)
S211 1-553-856-00 SWITCH, KEYBOARD (SLEEP, RADIO ON)
S212 1-553-856-00 SWITCH, KEYBOARD (CLOCK)
S213 1-553-856-00 SWITCH, KEYBOARD (+, TUNE/TIME SET)
S214 1-553-856-00 SWITCH, KEYBOARD (-, TUNE/TIME SET)
S215 1-553-856-00 SWITCH, KEYBOARD (3)
S216 1-553-856-00 SWITCH, KEYBOARD (4)
MAIN MAIN KEY

– 22 –
Ref. No. Part No. Description Remark Ref. No. Part No. Description Remark
S217 1-553-856-00 SWITCH, KEYBOARD
(SNOOZE/DATA/SLEEP OFF)
S218 1-553-856-00 SWITCH, KEYBOARD (2)
*************************************************************
*1-671-842-11 TRANSFORMER BOARD
*******************
*1-535-771-11 TERMINAL (C793: AEP, AUS/C793L)
<CONNECTOR>
*CN301 1-564-706-11 PIN, CONNECTOR (SMALL TYPE) 4P
<TRANSFORMER>
!T301 1-433-600-11 TRANSFORMER, POWER (C793: US, CND)
!T301 1-433-601-11 TRANSFORMER, POWER
(C793: AEP, AUS/C793L)
************************************************************
MISCELLANEOUS
**************
!10 1-555-795-00 CORD, POWER (C793: AEP/C793L: FR)
!10 1-696-572-21 CORD, POWER (C793L: UK)
!10 1-783-817-11 CORD, POWER (C793: US, CND)
!10 1-790-431-11 CORD, POWER (C793: AUS)
SP301 1-504-748-21 SPEAKER (6.6cm)
L1 1-754-039-11 ANTENNA, FERRITE-ROD (AM) (C793)
L1 1-754-040-11 ANTENNA, FERRITE-ROD (LW/MW) (C793L)
************************************************************
ACCESSORIES & PACKING MATERIALS
*******************************
3-865-471-11 MANUAL, INSTRUCTION
(ENGLISH, FRENCH, GERMAN, DUTCH)
(C793: CND, AEP, AUS/C793L)
3-865-471-21 MANUAL, INSTRUCTION (ENGLISH)(C793: US)
3-865-471-31 MANUAL, INSTRUCTION
(ENGLISH, ITALIAN, SPANISH, PORTUGUESE)
(C793: AEP/C793L: FR)
3-865-471-41 MANUAL, INSTRUCTION
(ENGLISH, SWEDISH, DANISH, FINNISH)
(C793: AEP)
MAIN KEY TRANSFORMER
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 numéro spécifié.
ICF-C793/C793L
Sony Corporation
Personal A&V Products Company
9-926-955-11
99B0568-1
Printed in Japan © 1999. 2
Published by Quality Engineering Dept.
(Shinagawa)

MICROFILM
SERVICE MANUAL
ICF-C793
FM/AM PLL SYNTHESIZED CLOCK RADIO
ICF-C793L
FM/MW/LW PLL SYNTHESIZED CLOCK RADIO
US Model
Canadian Model
E Model
Australian Model
ICF-C793
AEP Model
ICF-C793/C793L
UK Model
ICF-C793L
SPECIFICATIONS
ICF-C793/C793L
Photo: ICF-C793L
Ver 1.1 1999.06

– 2 –
TABLE OF CONTENTS
1. SERVICING NOTES ................................................ 3
2. GENERAL ................................................................... 4
3. DISASSEMBLY ......................................................... 6
4. ELECTRICAL ADJUSTMENTS......................... 7
5. DIAGRAMS
5-1. Block Diagram ................................................................ 9
5-2. IC Pin Function Description ........................................... 11
5-3. Schematic Diagram ......................................................... 13
5-4. Printed Wiring Boards (SUFFIX-11) ............................. 15
5-5. Printed Wiring Boards (SUFFIX-12) ............................. 17
6. EXPLODED VIEWS ................................................ 19
7. ELECTRICAL PARTS LIST ............................... 21
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.
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.
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 microamperes).
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 2V AC 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

– 3 –
CF2
CF3
mark
Mark Center frequency
red 10.70 MHz
blue 10.67 MHz
orange 10.73 MHz
black 10.64 MHz
white 10.76 MHz
HOW TO CHANGED THE CERAMIC FILTERS
This model is used two ceramic filters of CF2 and CF3.
You must used same type of color marked ceramic filters in order
to meet same specifications.
Therefore, the ceramic filter must changed two pieces together
since it’s supply two pieces in one package as a spare parts.
SECTION 1
SERVICING NOTES
•Discrimination of MAIN board
– MAIN BOARD (Component Side) –
1-671-839-11
or
1-671-839-12