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AUDIO POWER SPECIFICATIONS (US model)
POWER OUTPUT AND TOTAL HARMONIC DISTORTION
With 8-ohm loads, both channels driven from 100 ­ 10,000 Hz; rated
1.0 W per channel minimum RMS power, with no more than 10% total
harmonic distortion in AC operation.
CD player section
System:
Compact disc digital audio system
Laser diode properties:
Material: GaAlAs
Wavelength: 780 nm
Emission duration: Continuous
Laser output: Less than 44.6
µW
(This output is the value measured at a distance of
about 200 mm from the objective lens surface on
the optical pick-up block with 7 mm aperture.)
Frequency response:
20 ­ 20,000 Hz
dB
Wow and flutter:
Below measurable limit
Radio section
Frequency range:
FM: 87.5 ­ 108 MHz
AM: 530 ­ 1,710 kHz
SERVICE MANUAL
ICF-CD837
Ver. 1.1 2005.07
9-879-522-02
2005G04-1
© 2005.07
US Model
Canadian Model
E Model
Australian Model
CD
Model Name Using Similar Mechanism
ICF-CD832
Section
CD Mechanism Type
KSM-213CDP
Optical Pick-up Name
KSS-213C
Sony Corporation
Personal Audio Group
Published by Sony Engineering Corporation
FM/AM CD CLOCK RADIO
+1
­1.5
SPECIFICATIONS
General
Time display:
12-hour system
Speaker:
66 mm (2 5 /8 inches) dia., 8
Power outputs:
1 W + 1 W (at 10% harmonic distortion)
Power requirements:
120 V AC, 60 Hz (Except Australian model)
230 V AC, 50 Hz (Australian model)
Dimensions:
Approx. 246
× 96 × 210 mm (w/h/d)
(Approx. 9 3/4
× 3 7/8 × 8 3 /8 inches) incl.
projecting parts and controls
Mass:
Approx. 1,750 g (3 lb. 86 oz.)
Design and specifications are subject to change without
notice.


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ICF-CD837
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE
WITH MARK 0 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 PUBLISHED BY SONY.
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 dam-
aged by heat.
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK
OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic
breakdown because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic breakdown 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 objective lens.
CAUTION
Use of controls or adjustments or performance of proce-
dures other than those specified herein may result in haz-
ardous radiation exposure.
1.5 k
0.15 µF
AC
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
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
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. 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 2 V AC range are suit-
able. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
(Fig. A)
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE 0 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.


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TABLE OF CONTENTS
1. SERVICING NOTES
1-1. Cord Dressing (Power Cord) ............................................... 5
1-2. Pointer Alignment ............................................................... 5
2. GENERAL ............................................................................ 6
3. DISASSEMBLY
3-1. Cabinet (Upper) Assy .......................................................... 8
3-2. Front Panel Assy ................................................................. 8
3-3. Power Board ........................................................................ 9
3-4. Main Board Section ............................................................ 9
3-5. Main Board, CD Block Assy ............................................. 10
3-6. CD Mechanism Deck ........................................................ 10
3-7. CD Board .......................................................................... 11
3-8. Optical Pick-up ................................................................. 11
3-9. Lid (CD) ............................................................................ 12
3-10. LED Holder Assy .............................................................. 12
3-11. LED Indicator Element Unit ............................................. 13
3-12. Indicator Board, Drive Board ............................................ 13
4. ELECTRICAL ADJUSTMENTS
Tuner Section ......................................................................... 14
CD Section ............................................................................ 15
5. DIAGRAMS
5-1. Block Diagram ­ CD Section ­ ......................................... 17
5-2. Block Diagram ­ Main Section ­ ...................................... 18
5-3. Circuit Boards Location .................................................... 19
5-4. Printed Wiring Board ­ CD Section ­ ............................... 20
5-5. Schematic Diagram ­ CD Section ­ .................................. 21
5-6. Printed Wiring Boards ­ Main Section ­ .......................... 22
5-7. Schematic Diagram ­ Main Section ­ ............................... 23
5-8. Printed Wiring Boards ­ Display Section ­ ...................... 24
5-9. Printed Wiring Board ­ Key Section ­ .............................. 25
5-10. Schematic Diagram ­ Display Section ­ ........................... 26
5-11. Printed Wiring Board ­ Power Supply Section ­ .............. 27
5-12. Schematic Diagram ­ Power Supply Section ­ ................. 28
6. EXPLODED VIEWS
6-1. Cabinet Section ................................................................. 32
6-2. Front Panel Section ........................................................... 33
6-3. Upper Cabinet Section ...................................................... 34
6-4. Lower Cabinet Section ...................................................... 35
6-5. CD Block Section .............................................................. 36
6-6. CD Mechanism Section .................................................... 37
7. ELECTRICAL PARTS LIST ......................................... 38
ICF-CD837
· UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
· Unleaded solder melts at a temperature about 40
°C higher than
ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350
°C.
Caution: The printed pattern (copper foil) may peel away if
the heated tip is applied for too long, so be careful!
· Strong viscosity
Unleaded solder is more viscous (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
· Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.


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ICF-CD837
CHUCK PLATE JIG ON REPAIRING
On repairing CD section, playing a disc without the lid (CD), use
Chuck Plate Jig.
· Code number of Chuck Plate Jig: X-4918-255-1
SECTION 1
SERVICING NOTES
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
1. Turn ON the [POWER] button and press [CD] button to CD
position.
2. Open the CD lid.
3. Turn on S401 with screwdriver, etc. as following figure.
4. Press the N X (CD) button.
5. Confirm 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 three times for focus search.
S401


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ICF-CD837
1-1. CORD DRESSING
(POWER CORD)
1) Set the power cord as shown in the figure.
1-2. POINTER ALIGNMENT
power cord
MAIN board section
pointer
A
knob (tune)
1
Turn this in the arrow direction
until stopped.
2
Fit the protrusion on the
pointer in the hole A.
3
Align the notch on the boss
of the knob (tune) with the
direction of CV1.