Sony ICFCD-873 Service manual
ICF-CD873
SERVICE MANUAL
Ver 1.1 1999. 06
With SUPPLEMENT 1
(9-927-109-81)
SPECIFICATIONS
US Model
Canadian Model
AEP Model
Australian Model
Model Name Using Similar Mechanism CFD-550
Optical Device Name KSM-213BAN
Optical Pick-UP Name KSS-213B
MICROFILM
FM/AM CD CLOCK RADIO
SECTION 1
SERVICING NOTES
TABLE OF CONTENTS
1. SERVICING NOTE.................................................. 2
2. GENERAL ................................................................... 4
3. DISASSEMBLY ......................................................... 6
4. POWER CORD SETTING................................... 8
5. ELECTRICAL ADJUSTMENTS......................... 9
Tuner Section .................................................................. 9
CD Section ...................................................................... 10
Main Clock Section......................................................... 12
6. DIAGRAMS
6-1. Block Diagram – CD Section – ..................................... 15
6-2. Block Diagram – TUNER Section – ............................. 17
6-3. Block Diagram – MAIN Section – ................................ 19
6-4. Printed Wiring Board – MAIN Section –...................... 23
6-5. Schematic Diagram – MAIN Section –......................... 27
6-6. Schematic Diagram – POWER SUPPLY Section –...... 32
6-7. Printed Wiring Board – POWER SUPPLY Section – ... 35
6-8. IC Pin Function Description ........................................... 41
7. EXPLODED VIEWS ................................................ 43
8. ELECTRICAL PARTS LIST ............................... 47
SAFETY CHECK-OUT
After correcting the original service problem, perform the following 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
The AC 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. Follo w 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” indication is 0.75 V, so analog meters must have an accurate lowvoltage scale. The Simpson 250 and Sanwa SH-63Trd are examples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V A C range are suitable. (See Fig. A)
To Exposed Metal
Parts on Set
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 MANU AL OR IN SUPPLEMENTS PUBLISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS P AR UNE MARQUE !
SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE
DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ
DE FONCTIONNEMENT. NE REMPLACER CES COMPOSANTS QUE PAR DES PIÈCES SONY DONT LES
NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY.
AC
1.5 k
0.15 µF
Fig. A. Using an AC voltmeter to check AC leakage.
Ω
Earth Ground
voltmeter
(0.75 V)
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation exposure.
This appliance is classified as a CLASS 1 LASER product.
The CLASS 1 LASER PRODUCT MARKING is located on
the rear exterior.
Laser component in this product is capable of emitting radiation
exceeding the limit for Class 1.
– 2 –
2
MODEL IDENTIFICATION – Rear View –
W
S
US, Canadian models: AC: 120 V 60 Hz 20
Other models: AC: 220 – 230 V 50 Hz 20 W
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.
mark
MODEL NO. ICF-CD873
MADE IN MALAYSIA
Mark Center frequency
CF
red 10.70 MHz
blue 10.67 MHz
orange 10.73 MHz
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic break-down because of the potential difference generated
by the charged electrostatic load, etc. on clothing and the human
body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused
on the disc reflective surface by the objective lens in the optical
pick-up block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objectiv e lens.
CHUCK PLATE JIG ON REPAIRING
On repairing CD section, playing a disc without the CD lid, use
Chuck Plate Jig.
• Code number of Chuck Plate Jig: X-4918-255-1
CF3
black 10.64 MHz
white 10.76 MHz
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 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.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
1. Open the CD lid.
2. Turn on S424 as following figure.
3. Conf irm that the laser diode emission while observing the objecting lens. When there is no emission, Auto Power Control
circuit or Optical Pick-up is broken.
Objective lens moves up and down once for the focus search.
Insert a precision
screwdriver and
push S424.
laser diode
emission
– 3 –
SECTION 2
GENERAL
This section is extracted from
instruction manual.
– 4 –
– 5 –
• This set can be disassembled in the order shown below.
SECTION 3
DISASSEMBLY
Set
Note: Follow the disassembly procedure in the numerical order given.
Upper cabinet
section
CD lid assy
Main board section Optical pick-up section
UPPER CABINET SECTION
3
two flat wires
(CN201, 202)
2
upper cabinet section
CD LID ASSY
4
connector
(CN204)
1
five screws
(P3
2
Open the CD lid assy.
7
Remove the CD lid
assy.
×
14)
1
three screws
(P3
×
14)
3
screw
(B3 × 10)
4
damper
5
spring
(CD open)
1
Pull the button (open).
6
two bosses
– 6 –
MAIN BOARD SECTION
1
2
net assy
3
Pull the button (open).
twelve
claws
8
flat wire
(CN101)
4
Open the CD lid.
5
screw
(B3 × 10)
8
flat wire
(CN402)
1
two claws
OPTICAL PICK-UP SECTION
6
two screws
(PWH2.6 × 10)
2
claw
6
four screws
(P3 × 14)
3
CD chassis
7
optical pick-up
section
6
two screws
(PWH2.6 × 10)
7
main board
section
6
three screws
(P3 × 14)
5
connector
(CN502)
– 7 –
1
screw
(BTP3 × 8)
4
flat wire
(CN501)
SECTION 4
POWER CORD SETTING
Set the power cord as illustrated below, then install the lower cabinet section.
Power Cord
lower cabinet section
– 8 –
SECTION 5
r
r
FM RF SSG
Carrier frequency: 98 MHz
Modulation: 400 Hz, 30% FM modulation
Output level: 0.1 V (100 dB)
MAIN board
TP12 (FM IN)
0.01 µF
set
1 µF
TP8 (VCO)
+
–
frequency counter
33 k
Ω
TP7 (+B)
+
MAIN board
ELECTRICAL ADJUSTMENTS
TUNER SECTION 0 dB=1 µV
[AM]
Setting:
Function : RADIO
Band switch: AM
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
[FM]
Setting:
Function : RADIO
Band switch: 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
TP12 (FM IN)
0.01 µF
set
digital voltmeter
32
Ω
2
jack (J301)
32
Ω
2
jack (J301)
level mete
+
–
level mete
+
–
AM IF ADJUSTMENT
Adjust for a maximum reading on level meter
T1 450 kHz
AM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L4 530 kHz 2.8 V
Confirmation 1,710 kHz 9.5V
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L3 580 kHz
CT2 1,490 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part Frequency Display Reading on Digital Voltmeter
L2 87.5 MHz 2.1 V
Confirmation 108 MHz 8.5 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L1 87.5 MHz
CT1 108 MHz
Adjustment Location: MAIN board (See page 11)
FM VCO Adjustment
Setting:
100 k
MAIN board
TP53 (VT)
Ω
• 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.
Procedure:
1. Connect the frequency counter to TP7, 8 as shown the figure
below.
2. Tune the set to 98 MHz.
3. Adjust RV1 for 76 kHz reading on the frequency counter.
Specified Value: 75.95 to 76.05 kHz
Adjustment Location: MAIN board (See page 13)
– 9 –
CD SECTION
Note:
Tracking Balance Adjustment and Tracking Gain Adjustment are
done automatically in this set.
TEST MODE
1. Press the CD LID OPEN/CLOSE DET switch (S424) on the
PUSH SWITCH board.
2. Under standby condition (when the clock appear in the display), short the BP (CD TEST AUTO).
Note: If the power is supplied to the microprocessor once, it is backed up
for 3 minutes, therefore the TEST mode will not be activ ated within
3 minutes even if the power is turned on again. In this case, short
instantaneously the BP (CD TEST MANUAL).
3. Press the ^ key, and the focus search is repeated.
At this time, check that the optical pick-up objective lens mov es
smoothly without a sticking or noise.
4. Load the test disc (YEDS-18: Part No. 3-702-101-01), and perform automatic adjustment after the focus search succeded.
5. After automatic adjustment is finished, move the sled motor
to the center. At this time, keep pressing the + and =
keys to confirm that optical pick-up moves smoothly via most
inside track → most outside track → most inside track without a sticking or noise.
6. Confirm the traverse waveform.
7. Press the [WAKEUPTRACK] key.
8. The tracking servo and the sled servo are turned on, the mute
is cancelled.
9. Playback the 2nd track.
10. Adjust the RF and jitter waveforms.
Connecting points: MAIN Board (See page 13)
Focus Bias Adjustment
This adjustment is to be done when the optical block is replaced.
Connection:
oscilloscope
(AC range)
MAIN board
TP503 (RF)
TP504 (VREF)
+
–
Adjustment Procedure:
1. Connect the oscilloscope to TP504 (VREF) and TP503 (RF)
on the MAIN board.
2. Insert the test disc (YEDS-18: Part No.3-702-101-01) and press
^ key to play.
3. Move the optical pick-up to the music area on the disc to enable easy visibility of the eye pattern by + or = key
pressing.
4. Adjust RV501 so that the oscilloscope waveform is as shown
in the figure below (eye pattern).
A good eye pattern means that the diamond shape (≈) in the
center of the waveform can be clearly distinguished.
• RF signal reference waveform (eye pattern)
VOLT/DIV: 0.2 V
TIME/DIV: 500 ns
1.3
±
0.5 Vp-p
When observing the eye pattern, set the oscilloscope
for AC range and raise vertical sensitivity.
Adjustment Location: MAIN Board (See page 13)
– 10 –
Focus Gain Adjustment
A frequency response analyzer is necessary in order to perform
this adjustment exactly.
However, this gain has a margin, so even if it is slightly off, there
is no problem. Therefore, do not perform this adjustment.
Focus gain determines the optical pick-up follow-up (vertical and
horizontal) relative to mechanical noise and mechanical shock
when the 2-axis device operate.
However , as these reciprocate, the adjustment is at the point where
both are satisfied.
• When gain is raised, the noise when the 2-axis device operates
increases.
• When gain is lowered, mechanical shock and skipping occurs
more easily.
• When gain adjustment is off, the symptoms below appear.
Procedure:
1. Keep the set horizontal.
If the set is not horizontal, this adjustment cannot be per-
(
formed due to the gravity against the 2-axis device
2. Insert the test disc (YEDS-18) and press the ^ button.
3. Connect the oscilloscope BT (FEO) and TP504 (VREF) on
the MAIN board.
4. Adjustment RV502 on the MAIN board so that the waveform
is as shown in the figure below.
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
100 mV
)
Symptoms
• The time until music starts becomes longer for
STOP → PLAY or automatic selection.
(=, + buttons pressed)
(Normally takes about 2 seconds)
• Music does not start and disc continues to
rotate for STOP → PLAY or automatic
selection.
(=, + buttons pressed)
• Sound is interrupted during PLAY.
Or time counter display stops progressing.
• More noise during 2-axis device operation
Gain Focus
low
–
–
high
The following is a simple adjustment method.
– Primary Adjustment –
Note: Since exact adjustment cannot be performed, remember the posi-
tions of the controls before performing the adjustment. If the positions after the primary adjustment are only a little different, return
the controls to the original position.
Connection:
oscilloscope
MAIN board
BP (FEO)
TP504 (VREF)
+
–
0 V
• Incorrect Examples (DC level changes more than on adjusted
waveform)
low focus gain
high focus gain
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
200 mV
0 V
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
75 mV
0 V
Adjustment Location: MAIN Board (See page 13)
– 11 –
MAIN CLOCK SECTION
Main Clock Adjustment
Connection:
Ω
Ω
adjustment
+5
IN
GND
100 k
INVERTER
(TC7W04F)
jig
OUT
GND
Ω
1000 pF
100 k
10 : 1 probe
Ω
OUT
GND
MAIN board
TP (+5 V)
TP401 (4.194 MHz)
TP GND (SHIELD)
Adjustment jig:
+5 V
IN
GND
+
0.5 pF
47 uF
1 M
1 M
Procedure:
1. Connect the frequency counter as the above figures.
2. Adjust CT401 for 4.2495 MHz reading on the frequency
counter.
Specified Value: 4.2490 to 4.2500 MHz
frequency counter
+
–
– 12 –
Adjustment Location and Connecting Points:
T1 AM IF Adjustment
CT401 Main Clock Adjustment
RV501 Focus Bias Adjustment
RV502 Focus Gain Adjustment
RV1 FM VCO Adjustment
AM Frequency Coverage
Adjustment
L4
L2 FM Frequency Coverage
Adjustment
L3
CT2
AM T rac king Adjustment
CT1
L1
FM T rac king Adjustment
– MAIN BOARD (Component Side) –
– MAIN BOARD (Conductor Side) –
BP (CD TEST AUTO)
BP (FEO)
BP (CD TEST MANUAL)
TP8
(VCO)
TP7
(+B)
TP12 (FM IN)
TP504 (VREF)
TP53 (VT )
TP503 (RF)
TP (+5 V)
C429
TP GND
(SHIELD)
TP401
(4.194 MHz)
+
– 13 –
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