ICF-CD873L - Sony Audio Service Manual (repair manual)

Model
ICF-CD873L
Pages
36
Size
3.64 MB
Type
PDF
Document
Service Manual
Brand
Device
Audio
File
icf-cd873l.pdf
Date

View Sony ICF-CD873L Service Manual online

MICROFILM
SERVICE MANUAL
FM/MW/LW CD CLOCK RADIO
AEP Model
UK Model
SPECIFICATIONS
ICF-CD873L
Model Name Using Similar Mechanism
CFD-550
Optical Device Name
KSM-213BAN
Optical Pick-UP Name
KSS-213B
Supplied accessories:
Instruction manual (1)
Ver 1.0  1999. 05
– 2 –
TABLE  OF  CONTENTS
1.
SERVICING  NOTES
...............................................
3
2.
GENERAL
...................................................................
4
3.
DISASSEMBLY
.........................................................
5
4.
POWER  CORD  SETTING
...................................
7
5.
ELECTRICAL  ADJUSTMENTS
Tuner Section ..................................................................
8
CD Section ......................................................................
9
Main Clock Section ......................................................... 11
6.
DIAGRAMS
6-1. Block Diagram  – CD Section – ..................................... 13
6-2. Block Diagram  – TUNER Section – ............................. 15
6-3. Block Diagram  – MAIN Section – ................................ 17
6-4. Printed Wiring Boards  – MAIN Section – .................... 22
6-5. Schematic Diagram  – MAIN Section – ......................... 25
6-6. Schematic Diagram  – POWER SUPPLY Section – ...... 30
6-7. Printed Wiring Boards
  – POWER SUPPLY Section – ...................................... 33
6-8. IC Pin Function Description ........................................... 39
7.
EXPLODED  VIEWS
................................................ 41
8.
ELECTRICAL  PARTS  LIST
............................... 45
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.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation 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.
The following caution label is located inside the unit.
– 3 –
SECTION  1
SERVICING  NOTES
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.
The laser diode in the optical pick-up block may suffer electro-
static 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 emis-
sion, observe from more than 30 cm away from the objective lens.
NOTES  ON  HANDLING  THE  OPTICAL  PICK-UP
BLOCK  OR  BASE  UNIT
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C dur-
ing 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 dam-
aged by heat.
Insert a precision 
screwdriver and 
push S424.
laser diode 
emission
LASER  DIODE  AND  FOCUS  SEARCH  OPERATION
CHECK
1. Open the CD lid.
2. Turn on S424 as following figure.
3. Confirm that the laser diode emission while observing the ob-
jecting 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.
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
– 4 –
SECTION  2
GENERAL
This section is extracted from
instruction manual.
– 5 –
UPPER  CABINET  SECTION
CD  LID  ASSY
SECTION  3
DISASSEMBLY
Note:
 Follow the disassembly procedure in the numerical order given.
• This set can be disassembled in the order shown below.
Set
Upper cabinet
section
CD lid assy
Main board section
Optical pick-up section
1
five screws
(P3 
×
 14)
2
upper cabinet section
3
two flat wires
(CN303, 304)
4
connector
(CN306)
1
three screws
(P3 
×
 14)
1
Pull the button (open).
6
two bosses
2
Open the CD lid assy.
7
Remove the CD lid 
assy.
3
screw
(B3 
×
 10)
4
damper
5
spring
(CD open)
– 6 –
MAIN  BOARD  SECTION
OPTICAL  PICK-UP  SECTION
4
Open the CD lid.
6
four screws
(P3 
×
 14)
6
three screws
(P3 
×
 14)
5
screw
(B3 
×
 10)
3
Pull the button (open).
1
twelve 
claws
2
net assy
1
two claws
7
flat wire
(CN301)
8
main board 
section
7
flat wire 
(CN402)
3
CD chassis
6
two screws
(PWH2.6 
×
 10)
1
screw
(BTP3 
×
 8)
4
flat wire
(CN501)
7
optical pick-up 
section
6
two screws
(PWH2.6 
×
 10)
2
claw
5
connector
(CN502)
– 7 –
SECTION  4
POWER  CORD  SETTING
Set the power cord as illustrated below, then install the lower cabinet section.
Power Cord
lower cabinet section
– 8 –
AM  IF  ADJUSTMENT
Adjust for a maximum reading on level meter
T1
450 kHz
MW  FREQUENCY  COVERAGE  ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L4
531 kHz
2.8 V
Confirmation
1,602 kHz
less than 10.5 V
MW  TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L3-1
621 kHz
CT2
1,404 kHz
LW  FREQUENCY  COVERAGE  ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
CT4
153 kHz
2.2 V
Confirmation
279 kHz
less than 9.5 V
LW  TRACKING  ADJUSTMENT
Adjust for a maximum reading on level meter
L3-2
162 kHz
CT3
243 kHz
FM  FREQUENCY  COVERAGE  ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L2
87.5 MHz
2.1 V
Confirmation
108 MHz
9.7 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 12)
FM  VCO Adjustment
Setting:
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 12)
SECTION  5
ELECTRICAL  ADJUSTMENTS
TUNER  SECTION
0 dB=1 µV
[MW/LW]
Setting:
Function
: RADIO
Band switch : MW or LW
[FM]
Setting:
Function
: RADIO
Band switch : FM
• 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.
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
32 
2
 (headphone) jack (J301)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
+
level meter
2
 (headphone) jack (J301)
set
32 
0.01 
µ
F
MAIN board
TP12 (FM IN)
digital voltmeter
100 k
MAIN board
TP53 (VT)
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 
µ
F
set
µ
F
TP8 (VCO)
+
frequency counter
33 k
TP7 (+B)
+
MAIN board
– 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 appears in the dis-
play), 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 activated within
3 minutes even if the power is turned on again. In this case, short
instantaneously the BP (CD TEST MANUAL).
3. Press the  fl key, and the focus search is repeated.
At this time, check that the optical pick-up objective lens moves
smoothly without a sticking or noise.
4. Load the test disc (YEDS-18: Part No. 3-702-101-01), and per-
form automatic adjustment after the focus search succeeded.
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 with-
out a sticking or noise.
6. Confirm the traverse waveform.
7. Press the [WAKE UP TRACK] 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 12)
Focus Bias Adjustment
This adjustment is to be done when the optical block is replaced.
Connection:
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
fl key to play.
3. Move the optical pick-up to the music area on the disc to en-
able 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)
Adjustment Location: MAIN Board (See page 12)
MAIN board
TP503 (RF)
TP504 (VREF)
+
oscilloscope
(AC range)
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.
– 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.
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 posi-
tions after the primary adjustment are only a little different, return
the controls to the original position.
Connection:
• 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
Symptoms
low
high
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 fl 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.
• Incorrect Examples (DC level changes more than on adjusted
waveform)
)
(
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
100 mV
0 V
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
200 mV
0 V
VOLT/DIV: 100 mV
TIME/DIV: 2 mS
75 mV
0 V
low focus gain
high focus gain
MAIN board
BP (FEO)
TP504 (VREF)
+
oscilloscope
Adjustment Location: MAIN Board (See page 12)

Download Sony ICF-CD873L Service Manual (Repair Manual)

Here you can view online and download Sony ICF-CD873L Service Manual in PDF. ICF-CD873L service manual will guide through the process and help you recover, restore, fix, disassemble and repair Sony ICF-CD873L Audio. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.