Sony ICF-S79, ICF-S79L, ICF-S79V Service Manual

ICF-S79/S79L/S79V

SERVICE MANUAL

Ver 1.1 1999. 11 With SUPPLEMENT-1 (9-925-738-81)

Photo: ICF-S79V

SPECIFICATIONS

US Model

ICF-S79V

AEP Model

ICF-S79/S79L

UK Model

ICF-S79L

MICROFILM

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.

ICF-S79

FM/AM SYNTHESIZED RADIO

ICF-S79L

FM/MW/LW SYNTHESIZED RADIO

ICF-S79V

TV/WEATHER/FM/AM SYNTHESIZED RADIO

This section is extracted from instruction manual.

SECTION 1

GENERAL

– 2 –

– 3 –

SECTION 2

DISASSEMBLY

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

REAR CABINET

BATT lead (red)

two claws

antenna lead

rear cabinet

six screws (BTP 3 × 25)

battery case li

BATT lead (white)

– 4 –

SECTION 3

FM antenna

ground (JW17)

FM FREQUENCY

COVERAGE

AM (MW)

FREQUENCY

COVERAGE

L5 CT3

AM (MW)

TRACKING

TV TRACKING

(ICF-S79V only)

TV IF

(ICF-S79V only)

TV FREQUENCY

COVERAGE

(ICF-S79V only)

CT5

LW FREQUENCY

COVERAGE

(ICF-S79L only)

TV antenna

ground (JW20)

FM/TV

antenna input

(JW18)

CT1

AM IF

TRACKING

CT4

CT2 L5

LW TRA CKING

(ICF-S79L only)

MW LWL5

IC1

IC2

(VT)

ELECTRICAL ADJUSTMENTS

0dB=1 µV

[FM/TV Section]

Setting:

BAND switch: FM1 or TV

FM RF SSG

0.01

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

FM lead wire antenna terminal

[AM (LW/MW) Section]

Setting:

BAND switch: AM (MW) or LW

Put the lead-wire

AM RF SSG

30% amplitude modulation by 400 Hz signal Output level: as low as possible

antenna close to the set.

set

speaker terminal

level meter

+ –

speaker terminal

level meter

+ –

FM FREQUENCY COVERAGE ADJUSTMENT

Adjust for a reading on digital voltmeter.

L8 87.5 MHz (TV 2 ch)

Confirm 108.0 MHz

Note: Not use the FM RF signal generator in this adjustment.

2.3 ± 0.1 V (1.0 ± 0.1 V)

8.5 ± 0.5 V (12.5 ± 0.5 V)

( ): ICF-S79V

FM TRACKING ADJUSTMENT

Adjust for a maximum reading on level meter.

L6 87.5 MHz (TV 2 ch (59.75 MHz))

CT4 108.0 MHz

( ): ICF-S79V

ICF-S79L only

LW FREQUENCY COVERAGE ADJUSTMENT

Adjust for a reading on digital voltmeter.

CT5 153 kHz 2.3 ± 0.1 V

Confirm 279 kHz 8.5 ± 0.5 V

Note: Not use the AM RF signal generator in this adjustment.

ICF-S79L only

LW TRACKING ADJUSTMENT

Adjust for a maximum reading on level meter.

L5 (LW side) 162 kHz

CT2 243 kHz

Adjustment and Connection Location:

[MAIN BOARD] (Component Side)

MAIN board

(VT)

digital voltmete

+ –

Repeat the procedures in each adjustment several times, and the frequency coverage and tracking adjustments should be finally done by the trimmer capacitors.

ICF-S79V only

TV FREQUENCY COVERAGE ADJUSTMENT

Adjust for a reading on digital voltmeter.

L2 WEATHER 2 ch 1.0 ± 0.1 V

Confirm TV 13 ch 10 ± 0.5 V

Note: Not use the FM RF signal generator in this adjustment.

ICF-S79V only

TV TRACKING ADJUSTMENT

Adjust for a maximum reading on level meter.

L1 WEATHER 2 ch (162.40 MHz)

CT1 TV 13 ch (215.75 MHz)

ICF-S79V only

Adjust for a maximum reading on level meter.

TV IF ADJUSTMENT

T1 10.7 MHz

AM (MW) FREQUENCY COVERAGE ADJUSTMENT

Adjust for a reading on digital voltmeter.

L9 531 kHz (530 kHz) 2.8 ± 0.1 V

Confirm 1,602 kHz (1,710 kHz) 9.5 ± 0.5 V

Note: Not use the AM RF signal generator in this adjustment.

AM (MW) TRACKING ADJUSTMENT

Adjust for a maximum reading on level meter.

L5 <MW side> 621 kHz (590 kHz)

CT3 1,395 kHz (1,490 kHz)

AM IF ADJUSTMENT

Adjust for a maximum reading on level meter.

T2 455 kHz

( ): ICF-S79V

< >: ICF-S79L

( ): ICF-S79V

[MAIN BOARD] (Conductor Side)

– 5 –

– 6 –

ICF-S79/S79L/S79V

4-1. PRINTED WIRING BOARDS

SECTION 4

DIAGRAMS

HOW TO CHANGE THE CERAMIC FILTERS

This model is used two ceramic filters of CF1, CF3. Y ou must use same type of color marked cer amic filters in order to meet same specifications. Therefore, the ceramic filter must change two pieces together since it's supply two pieces in one package as a spare parts.

Mark Center frequency

CF3

mark

CF1

red 10.70 MHz

blue 10.67 MHz

orange 10.73 MHz

black 10.64 MHz

white 10.76 MHz

Semiconductor Location

Ref. No. Location Ref. No. Location

D1 G-1 Q1 F-1 D2 F-1 Q2 E-4 D3 E-2 Q3 I-6 D4 E-4 Q4 G-7 D5 H-2 Q5 E-6 D6 H-7 Q6 B-7 D7 G-6 Q7 H-6 D8 F-7 Q9 E-5 D9 E-2 Q10 D-6 D10 B-2 Q11 C-2 D11 B-2 Q12 A-2 D12 C-7 Q13 D-7 D13 C-7 Q14 C-7 D14 H-7 Q15 D-2

IC1 F-2 Q17 A-3 IC2 E-7 IC3 C-7 IC4 C-6 IC5 C-6 IC6 B-5

Note on Printed Wiring Board:

• : parts extracted from the component side.

• : indicates side identified with part number.

•

• : Pattern from the side which enables seeing.

: internal component.

Q16 D-1

– 7 –

– 8 –

4-2. SCHEMATIC DIAGRAM (ICF-S79/S79L) • See page 11 for Waveforms and IC Block Diagrams.

ICF-S79/S79L/S79V

Note on Schematic Diagram:

• All capacitors are in µF unless otherwise noted. pF: µµF 50 WV or less are not indicated except for electrolytics and tantalums.

• All resistors are in Ω and 1/ specified.

• ¢ : internal component.

• : panel designation.

•

B+: B+ Line.

• : adjustment for repair.

• Power voltage is dc 4.5 V and fed with regulated dc power

supply from battery terminal.

• Voltages and waveforms are dc with respect to ground under no-signal (detuned) conditions. no mark : FM (TV 2 – 6 ch) ( ) : AM (MW) []: LW

W or less unless otherwise

• Voltages are tak en with a V OM (Input impedance 10 MΩ). V oltage variations may be noted due to normal production

tolerances.

• Waveforms are taken with a oscilloscope. V oltage variations may be noted due to normal production

tolerances.

• Circled numbers refer to waveforms.

• Signal path.

: FM : AM (MW/LW)

– 9 –

– 10 –

+ 15 hidden pages