Sony ICFC-470, ICFC-470-L Service manual

ICF-C470/C470L

SERVICE MANUAL

Ver 1.1 1999. 06 With SUPPLEMENT 1 (9-926-981-81)

Photo: ICF-C470

SPECIFICATIONS

US Model

Canadian Model

E Model

Australian Model

ICF-C470

AEP Model

ICF-C470/C470L

UK Model

ICF-C470L

MICROFILM

ICF-C470

FM/AM CLOCK RADIO

ICF-C470L

FM/MW/LW 3 BAND CLOCK RADIO

1. GENERAL ................................................................... 3

2. DISASSEMBLY ......................................................... 4

3. DIAL POINTER SETTING..................................... 5

4. POWER CORD SETTING ..................................... 6

5. ELECTRICAL ADJUSTMENTS.......................... 7

6. DIAGRAMS

6-1. Block Diagram ................................................................ 9

6-2. Printed Wiring Boards (ICF-C470) ................................ 11

6-3. Schematic Diagram (ICF-C470)..................................... 13

6-4. Printed Wiring Boards (ICF-C470L).............................. 15

6-5. Schematic Diagram (ICF-C470L) .................................. 17

7. EXPLODED VIEWS ................................................ 20

8. ELECTRICAL PARTS LIST ............................... 22

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 A C leaka ge from an y e xposed metal part to earth gr ound 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-63T rd are e xamples 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 MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

ATTENTION AU COMPOSANT AYANT RAPPORT

À LA SÉCURITÉ!

LES COMPOSANTS IDENTIFIÉS P AR UNE MARQ UE ! 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.

1.5 k

0.15 µF

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

Ω

Earth Ground

voltmeter (0.75 V)

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 Center frequency

mark

red 10.70 MHz

blue 10.67 MHz

orange 10.73 MHz

CF3

black 10.64 MHz

white 10.76 MHz

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.

– 2 –

SECTION 1

GENERAL

This section is extracted from instruction manual.

– 3 –

SECTION 2

)

DISASSEMBLY

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

CABINET (LOWER)

five screws

14)

(P3

cabinet (lower

MAIN BLOCK

buzzer board

two claws

power transformer

Break the soldering of speaker lead.

two claws

three claws for chassis

– 4 –

main block

three claws for PWB

SECTION 3

DIAL POINTER SETTING

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

dial pointer

Install the MAIN board.

– BOTTOM VIEW –

Turn shaft of CV1 to the

arrow

direction fully.

Turn the knob (VOL) to the

arrow

direction fully.

Turn VR1 to the arrow

direction fully.

Turn the knob (tuning) to the

arrow

direction fully.

– 5 –

Set the power cord as illustrated below, then install the lower cabinet.

FM antenna

SECTION 4

POWER CORD SETTING

power cord

lower cabinet

– 6 –

SECTION 5

ELECTRICAL ADJUSTMENTS

0 dB = 1 µV

[AM (MW/LW)*] *AM : ICF-C470

MW/LW: ICF-C470L

Setting:

Band switch: AM (MW/LW)

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.

set

[FM]

Setting:

Band switch: FM

FM RF signal

generator

0.01 µF

22.5 kHz frequency deviation by 400 Hz signal Output level: as low as possible

MAIN board TP (FM ANT)

set

• 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 8)

MAIN board TP (SPK +)

level meter

Ω

+ –

MAIN board TP (SPK –)

MAIN board TP (SPK +)

level meter

Ω

MAIN board TP (SPK –)

+ –

AM IF ADJUSTMENT