Sony ICFCD-837 Service manual

ICF-CD837

SERVICE MANUAL

Ver. 1.1 2005.07

Section

SPECIFICATIONS

US Model

Canadian Model

Australian Model

Model Name Using Similar Mechanism ICF-CD832

CD Mechanism Type KSM-213CDP

Optical Pick-up Name KSS-213C

E Model

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 Wav elength: 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

+1 –1.5

General

Time display:

12-hour system

Speaker:

66 mm (2 5 ⁄8 inches) dia., 8 Ω

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.

9-879-522-02

2005G04-1

FM/AM CD CLOCK RADIO

Sony Corporation

Personal Audio Group Published by Sony Engineering Corporation

ICF-CD837

CAUTION

Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure.

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.

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. 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” 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 AC range are suitable. (See Fig. A)

To Exposed Metal Parts on Set

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 pickup block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens.

0.15 µF

1.5 k

Ω

Earth Ground

AC voltmeter (0.75 V)

Fig. A. Using an AC voltmeter to check AC leakage.

(Fig. A)

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 PA RT NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

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.

ICF-CD837

UNLEADED SOLDER

•

Boards requiring use of unleaded solder are printed with the leadfree 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.

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

SECTION 1

SERVICING NOTES

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

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

1-1. CORD DRESSING

(POWER CORD)

1) Set the power cord as shown in the figure.

ICF-CD837

power cord

1-2. POINTER ALIGNMENT

MAIN board section

Tu rn this in the arrow direction

until stopped.

of the knob (tune) with the direction of CV1.

pointer

pointer in the hole A.

Fit the protrusion on the

Align the notch on the boss

knob (tune)

ICF-CD837

CLOCK

TRACK

SET/

ALARM SET A

ALARM SET B

TIME SET

D IO

ALARM MODE selector

SECTION 2

GENERAL

This section is extracted from instruction manual.

RADIO

NAP

SLEEP

The CD button has a tactile dot.

CD/RADIO indicator

NAP indicator

REPEAT

NORMAL

BRIGHTNESS

HIGH

LOW

CD PLAY MODE

SHUFFLE

SHUFFLE REPEAT

AC power cord

FM wire antenna

VOLUME

BAND

TUNING

There is a tactile dot beside volume to show the direction to turn up the volume.

TRACK

ALARM

SECTION 3

DISASSEMBLY

• The equipment can be removed using the following procedure.

SET

3-1. CABINET (UPPER) ASSY

(Page 8)

ICF-CD837

3-2. FRONT PANEL ASSY

(Page 8)

3-3. POWER BOARD

(Page 9)

3-4. MAIN BOARD SECTION

(Page 9)

3-5. MAIN BOARD,

CD BLOCK ASSY (Page 10)

3-6. CD MECHANISM DECK

(Page 10)

3-8. OPTICAL PICK-UP

(Page 11)

3-9. LID (CD)

(Page 12)

3-10. LED HOLDER ASSY

(Page 12)

3-11. LED INDICATOR ELEMENT UNIT

(Page 13)

3-12. INDICATOR BOARD,

DRIVE BOARD (Page 13)

3-7. CD BOARD

(Page 11)

ICF-CD837

)

Note : Follow the disassembly procedure in the numerical order given.

3-1. CABINET (UPPER) ASSY

CNP602

cabinet (upper) assy

3-2. FRONT PANEL ASSY

two

screws

((+) BV tapping (B3))

CNP302

two

((+) BV tapping (B3)

four

screws

((+) BV tapping (B3))

screws

front panel assy

pointer

CNP402

3-3. POWER BOARD

two

screws

((+) BV tapping (B3))

bracket (trans)

POWER board

CNP901

CNP303

ICF-CD837

3-4. MAIN BOARD SECTION

1) Set the FM wire antenna as shown in the figure.

two

screws

((+) BV tapping (B3))

BRIGHTNESS board

four

screws

((+) BV tapping (B3))

MAIN board section

FM wire antenna

ICF-CD837

3-5. MAIN BOARD, CD BLOCK ASSY

CD block assy

CNP703

MAIN boar

3-6. CD MECHANISM DECK

three

((+) BV tapping (B3))

screws

chassis

CD cover

CD mechanism deck

two

screws

((+) PWH tapping (B2.6))

two

screws

((+) PWH tapping (B2.6))

3-7. CD BOARD

CNP701

Remove the two solders of motor.

CD board

ICF-CD837

Ver. 1.1

3-8. OPTICAL PICK-UP

optical pick-up

screw (+BVTT 2 × 6 (S))

gear (A)

Remove the two solders of motor.

claw

sled shaft

ICF-CD837

)

3-9. LID (CD)

lid (CD)

3-10. LED HOLDER ASSY

boss

spring (CD)

boss

panel (front) sub assy

two

screws

((+) BV tapping (B3))

two

((+) BV tapping (B3)

LED holder assy

screws

3-11. LED INDICATOR ELEMENT UNIT

CNP502

LED indicator element unit

Remove the solder.

DRIVE board

)

ICF-CD837

3-12. INDICATOR BOARD, DRIVE BOARD

claw

DRIVE board

two

screws

((+) BV tapping (B2.6)

INDICATOR board

ICF-CD837

SECTION 4

ELECTRICAL ADJUSTMENTS

TUNER SECTION 0 dB = 1 µV

• AM Section

Setting:

BAND switch: AM VOLUME control: MIN

AM RF signal generator

30% amplitude modulation by 400 Hz signal

• FM Section

Setting:

BAND switch: FM VOLUME control: MIN

FM RF signal generator

75 kHz frequency deviation by 1 kHz signal output level : as low as possible

Put the lead-wire antenna close to the set.

0.01

FM lead wire antenna termina

set

AM IF ADJUSTMENT