Sony HCDGX-20 Service manual

HCD-GX20

SERVICE MANUAL

Ver 1.4 2003.12

• HCD-GX20 is the tuner, deck, CD and amplifier section in MHC-GX20.

CD Section

Tape deck Model Name Using Similar Mechanism NEW Section T ape Transport Mechanism T ype CWL43FF48

US Model

Canadian Model

Model Name Using Similar Mechanism HCD-DX10 CD Mechanism Type CDM58F-K6 Optical Pick-up Name KSM-213D

AUDIO POWER SPECIFICATIONS:

POWER OUTPUT AND TOTAL HARMONIC DISTORTION:

with 6 ohms loads both channels driven, from 120 – 10,000 Hz; rates 60 watts per channel minimum RMS power, with no more than 10% total harmonic distortion from 250 milliwatts to rated output.

Total harmonic distortion less than 0.07%

Amplifier section

Continuous RMS power output (reference)

Total harmonic distortion less than 0.07% Inputs

AUDIO INPUT (phono jack):

Outputs PHONES (stereo mini jack):

Front speaker: accepts impedance of 6 to

CD player section

System Compact disc and digital Laser Semiconductor laser

(6 ohms at 1 kHz, 30 W)

60 + 60 watts (6 ohms at 1 kHz, 10% THD)

(6 ohms at 1 kHz, 30 W)

voltage 450 mV, impedance 47 kilohms

accepts headphones of 8 ohms or more

16 ohms

audio system (λ=780 nm)

Emission duration: continuous

SPECIFICATIONS

Frequency response 2 Hz – 20 kHz (±0.5 dB) Wavelength 780 – 790 nm Signal-to-noise ratio More than 90 dB Dynamic range More than 90 dB

Tape deck section

Recording system 4-track 2-channel stereo Frequency response 50 – 13,000 Hz (±3 dB),

Tuner section

FM stereo, FM/AM superheterodyne tuner

FM tuner section

Tuning range 87.5 – 108.0 MHz Antenna FM lead antenna Antenna terminals 75 ohms unbalanced Intermediate frequency 10.7 MHz

AM tuner section

Tuning range 530 –

Antenna AM loop antenna Antenna terminals External antenna terminal Intermediate frequency 450 kHz

using Sony TYPE I cassette

1,710 kHz (with the interval set at 10 kHz) 531 – 1,710 kHz (with the interval set at 9 kHz)

MINI HI-FI COMPONENT SYSTEM

General

Power requirements 120 V AC, 60 Hz Power consumption Dimensions (w/h/d) Mass Approx. 8.5 kg Supplied accessories: Remote Commander (1)

Design and specifications are subject to change without notice.

105 watts Approx. 280 × 325 × 412 mm

Batteries (2) AM loop antenna (1) FM lead antenna (1) Front speaker pads (8)

9-873-622-05

Sony Corporation

Home Audio Company Published by Sony Engineering Corporation

HCD-GX20

SAFETY CHECK-OUT

After cor recting the original service problem, perform the following safety checks before releasing the set to the customer: Check the antenna terminals, metal trim, “metallized” knobs, screws, and all other exposed metal parts for A C leakage. Check leakage as described below.

LEAKAGE

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 microamperes). 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 lo w-v oltage scale. The Simpson 250 and Sanwa SH-63Trd are e xamples of a passive VOM that is suitable. Nearly all battery operated digital multimeters that have a 2V AC range are suitable. (See 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 PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.

ATTENTION AU COMPOSANT AYANT RAPPORT

À LA SÉCURITÉ! LES COMPOSANTS IDENTIFÉS P AR UNE MARQUE 0 SUR LES DIAGRAMMES SCHÉMA TIQUES ET LA LISTE DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE REMPLACER CES COMPOSANTS QUE PAR DES PIÈSES SONY DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU DANS LES SUPPÉMENTS PUBLIÉS PAR SONY.

To Exposed Metal

Parts on Set

0.15 µF

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

1.5 kΩ

Earth Ground

Voltmeter (0.75 V)

HCD-GX20

Ver 1.3 2003.11

NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT

The laser diode in the optical pick-up block may suffer electrostatic 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 pickup block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens.

Laser component in this product is capable of emitting radiation exceeding the limit for Class 1.

TABLE OF CONTENTS

1. GENERAL ·········································································· 4

2. DISASSEMBLY································································ 6

2-1. Case (Top) ····································································· 6 2-2. CD Door········································································ 7 2-3. Front Panel Section·······················································7 2-4. CD Mechanism Deck (CDM58F-K6) ·························· 8 2-5. Tape Mechanism Deck (CWL43FF48)························· 8 2-6. REM Board and PANEL Board ···································· 9 2-7. KEY Board ··································································· 9 2-8. Back Panel Section ····················································· 10 2-9. SUB TRANS Board and VIDEO OUT Board············10 2-10. MAIN Board ······························································· 11 2-11. POWER Board···························································· 11 2-12. TRANS Board ···························································· 12 2-13. CD Board and DRIVER Board··································· 12 2-14. SPDL Board································································13 2-15. Optical Pick-up (KSM-213D)····································· 13 2-16. MOTOR Board, ADDRESS SENSOR Board ············ 14 2-17. Table (New), Cam (Control) and DC Motor··············· 14

3. TEST MODE ···································································· 15

4. ELECTRICAL ADJUSTMENTS ······························· 17

This appliance is classified as a CLASS 1 LASER product. The CLASS 1 LASER PRODUCT MARKING is located on the rear exterior.

CAUTION

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

Notes on chip component replacement

•Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be damaged by heat.

Flexible Circuit Board Repairing

•Keep the temperature of 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.

5. DIAGRAMS······································································19

5-1. Circuit Boards Location·············································· 19 5-2. Block Diagrams ·························································· 20 5-3. Printed Wiring Boards – CD Section (1/2) – ·············· 22 5-4. Printed Wiring Boards – CD Section (2/2) – ·············· 23 5-5. Schematic Diagram – CD Section – ··························· 24 5-6. Printed Wiring Board – MAIN Section – ··················· 25 5-7. Schematic Diagram – MAIN Section (1/4) – ············· 26 5-8. Schematic Diagram – MAIN Section (2/4) – ············· 27 5-9. Schematic Diagram – MAIN Section (3/4) – ············· 28 5-10. Schematic Diagram – MAIN Section (4/4) – ············· 29 5-11. Printed Wiring Boards – PANEL Section – ················ 30 5-12. Schematic Diagram – PANEL Section – ···················· 31 5-13. Printed Wiring Boards – POWER/TRANS Section – 32 5-14. Schematic Diagram – POWER/TRANS Section –····· 33 5-15. IC Pin Function Description ······································· 36

6. EXPLODED VIEWS ······················································ 38

6-1. Main Section ······························································· 38 6-2. Front Panel Section·····················································39 6-3. MAIN Board Section ·················································· 40 6-4. CD Mechanism Deck Section (CDM58F-K6) ··········· 41

7. ELECTRICAL PARTS LIST ······································· 42

HCD-GX20

SECTION 1

GENERAL

This section is extracted from instruction manual.

Main unit

ALPHABETICAL ORDER

A – E

AUDIO jacks ws (24) CD wj (11, 12, 18) CD SYNC 7 (18) Deck A w; (16, 17) Deck B qh (16 – 19) DISC 1 – 3 0 (11, 12) DISC SKIP/EX-CHANGE qa (10,

11) Disc tray 9 (10) DISPLAY 2 (16, 21) EFFECT ON/OFF qj (20)

123 549

wj wh wg

wf wd ws

G – Z

GAME wf (22, 24) GAME EQ ql (20, 24) GAME MIXING 4 (22) GROOVE 6 (20) MOVIE EQ 5 (20) MUSIC EQ 9 (20) PHONES jack qf REC PAUSE/START 8 (18) TAPE A/B wg (16, 18) TUNER/BAND wh (13 – 15, 18) VIDEO jack wd (24) VOLUME control qd

678

BUTTON DESCRIPTIONS

?/1 (power) 1 Z OPEN/CLOSE qs Z (deck B) qg M qk . qk > qk X qk N qk x qk m qk Z (deck A) wa

0 qa

wa w;

qg qh

qjqkql

HCD-GX20

Remote Control

ALPHABETICAL ORDER

A – G

CD ql (11, 12, 18) CLEAR w; (12) CLOCK/TIMER SELECT 2

(19, 23)

CLOCK/TIMER SET 9 (10, 19,

23) DISPLAY 6 (16, 21) D.SKIP 7 (11) ENTER qg (10, 12 – 14, 19, 23) EQ +/– qf (20) GAME 0 (22, 24) GROOVE qd (20)

BUTTON DESCRIPTIONS

?/1 (power) 4 M 5 . 5 > 5 X 5 N 5 m 5 x 5

12 34

O – Z

ON/OFF qh (20) PLAY MODE wa (11, 12, 17) PRESET +/– 5 (13 – 15) REPEAT 8 (11) SLEEP 1 (22) STEREO/MONO 8 (15) SURROUND qa (20) TAPE A/B 9 (16, 18) TUNER MEMORY qj (13, 14) TUNER/BAND qk (13 – 15, 18) TUNING +/– 5 (13 – 15) VOL +/– qs

Setting the clock

Press ?/1 to turn on the system.

Press CLOCK/TIMER SET on the remote.

Press . or > on the remote repeatedly to set the hour.

Press ENTER on the remote.

The minute indication flashes.

Press . or > on the remote repeatedly to set the minute.

Press ENTER on the remote.

The clock starts working.

To adjust the clock

1 Press CLOCK/TIMER SET on the remote. 2 Press . or > on the remote to select

“CLOCK SET”, then press ENTER on the remote.

3 Do the same procedures as step 3 to 6

above.

Note

The clock settings are canceled when you disconnect the power cord or if a power failure occurs.

w; ql qk

qj qh

6 7 8

9 0 qa qs

HCD-GX20

)

Ver 1.3 2003.11

Note : Disassemble the unit in the order as shown below.

SECTION 2

DISASSEMBLY

SET

BACK PANEL SECTION

CD BOARD AND DRIVER BOARD

OPTICAL PICK-UP (KSM-213D)

MOTOR BOARD,

CD DOOR CD MECHANISM DECK (CDM58F-K6)CASE (TOP) FRONT PANEL SECTION

SUB TRANS BOARD AND VIDEO OUT BOARD

MAIN BOARD

SPDL BOARD

ADDRESS SENSOR

BOARD

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

KEY BOARDREM BOARD AND PANEL BOARDTAPE MECHANISM DECK (CWL43FF48)

POWER BOARD

TABLE (NEW),CAM (CONTROL) AND DC MOTOR

TRANS BOARD

2-1. Case (Top)

two screws (Case 3 TP2)

screw (Case 3 TP2)

case (Side-L)

case (Top)

(+BVTP 3

screw

10)

four screws (+BVTP 3

case (Side-R)

10)

screw

(+BVTP 3

screw

(+BVTT 3

two screws

(Case 3 TP2)

(+BVTT 3

screw (Case 3 TP2)

screw

2-2. CD Door

)

CD mechanism deck (CDM58F-K6) 1

Turn the pulley to the direction of arrow.

Front panel side

CD door

HCD-GX20

pulley

2-3. Front Panel Section

connector 2p (CN682)

Pull-out the disc tray.

screw (+BVTP 3

10)

screw (+BVTP 3

front panel

10)

wire (flat type)

19p (CN733)

connector 3p (CN303)

screw (+BVTP 3

wire (flat type) 13p (CN207)

10)

connector 3p (CN201

connector 7p (CN202)

three screws (+BVTP 3

HCD-GX20

)

2-4. CD Mechanism Deck (CDM58F-K6)

CD mechanism deck (CDM58F-K6)

screw (+BVTP 3

connector 7p (CN734)

2-5. Tape Mechanism Deck (CWL43FF48)

tape mechanism deck

(CWL43FF48)

six

screws

(+BVTP 2.6

2-6. REM Board and PANEL Board

)

three claws

two claws

REM

claw

board

REM

HCD-GX20

board

eight

(+BVTP 2.6

screws

volume knob

2-7. KEY Board

three claws

PANEL board

two claws

KEY board

Remove the solderin

(three portions)

connector

13p (CN662)

1 four

screws

(+BVTP 2.6

HCD-GX20

)

2-8. Back Panel Section

5 back panel

connector

3p (CN903)

1 three

(+BVTP 3

2 two (+BVTT 3

screw

2-9. SUB TRANS Board and VIDEO OUT Board

6 cover (duct)

screw (+BVTP 3

10)

2 SUB TRANS board

4 VIDEO OUT board

screw (+BVTP 3

5 two

10)

screws (+BVTP 3

2-10. MAIN Board

)

MAIN board

screw (+BVTT 3

HCD-GX20

2-11. POWER Board

Three screws (+BVTT 3

connector 13p (CN503)

connector 13p (CN502)

Main board

Two screws (+BVTT 3

Heat sink

× 1

connector 13p (CN915)

6 POWER

Two screws (+BVTP 3

board

HCD-GX20

)

2-12. TRANS Board

screws (+BVTT 4× 6)

1 two

2 two

screws (+BVTT 4× 6)

3 TRANS board

2-13. CD Board and DRIVER Board

Screw (+BTTP M2.6 )

CD board

wire (flat type)

16p (CN731)

connector 10p (CN735)

Screw (+BTTP M2.6

DRIVER board

wire (flat type)

8p (CN702)

2-14. SPDL Board

)

HCD-GX20

Ver 1.3 2003.11

1 Remove solder (four places)

2 Remove solder (four places

3 SPDL board

2-15. Optical Pick-up (KSM-213D)

two stoppers (BU)

(KSM-213D)

two insulators

holder (BU) assy

optical pick-up

screw (+PTPWH M2.6)

screw (DIA. 12)

two insulators

two

screws (+PTPWH M2.6

two screws (+BVTP 2.6

HCD-GX20

2-16. MOTOR Board, ADDRESS SENSOR Board

screw (+PTPWH 2.6

tray

screw (+BVTP 2.6

MOTOR board

two screws (+BVTP 2.6

Remove the two solderings of motor.

connector 4p (CN722)

ADDRESS SENSOR board

Pull out the disc tray.

2-17. Table (New), Cam (Control) and DC Motor

*Cautions of an assembly

motor (TURN)

pulley (S)

4 gear (U)

2 screw (STEP)

3 cam (CONTROL)

5 pulley (S)

6 belt

7 DC

claw

motor (TURN)

claw

1 table (NEW)

SECTION 3

TEST MODE

HCD-GX20

[Change-over of AM Tuner Step between 9 kHz and 10 kHz]

•A step of AM channels can be changed ov er between 9 kHz and 10 kHz.

Procedure:

1. Press ?/1 button to turn the set ON.

2. Select the function “TUNER”, and press TUNER/BAND

button to select the BAND “AM”.

3. Press ?/1 button to turn the set OFF.

4. Press TUNER/BAND and ?/1 buttons simultaneously, and

the display of fluorescent indicator tube changes to “AM 9 k STEP” or “ AM 10 k STEP”, and thus the channel step is changed over.

[Cold Reset]

• The cold reset clears all data including preset data stored in the RAM to initial conditions. Execute this mode when returning the set to the customer.

Procedure:

1. Press three buttons x , GROOVE , and ?/1 simultaneously.

2. The fluorescent indicator tube displays “COLD RESET” and

the set is reset.

[Aging Mode]

This mode can be used for operation check of CD section and tape deck section.

• If an error occurred: The aging operation stops and is displayed status.

• If no error occurs: The aging operation continues repeatedly.

1. Operating method of Aging Mode

Turn on the main power and select “CD” of the function.

1) Set three discs in tray. Select ALL DISCS, and REPEAT OFF.

2) Load the tapes recording use into both decks.

3) Press three buttons x , GAME EQ , and

DISC SKIP/EX-CHANGE simultaneously.

4) Aging operations of CD and tape are started at the same time.

5) To exit the aging mode, perform [Cold Reset].

2. Aging mode in CD section

1) Operation during aging mode

• In the agining mode ,the program is excuted in the following sequence.

(1) The disc tray opens and closes. (2) The disc tray turns to select a disc 3. (3) The pickup accesses to the first track, and plays 3 seconds. (4) The pickup accesses to the last track, and plays 3 seconds. (5) The disc tray opens and closes. (6) The disc tray turns to select a disc 1. (7) The same operation starts like step (3). (8) After a disc 1 aging operation, a disc 2 is selected. (9) When an aging operation of a disc 3 is completed, the display

“AGING

∗∗∗∗” value increases.

(10) If no error occurs, the aging operation continues repeatedly.

2) Error display

Disc error

Display Error

E00D01022 Focus error (No disc) E00D02022 Sub Q error (Focus is good) E00D02023 TOC reading error E00D02014 Access error (Unable within regular time)

Mechanism error

Display Error

E00M__E_0 Error during opening tray E00M__C_2 EX-CHANGE disc error E00M__D_0 Error during closing tray

E00M__F_3 EX-OPEN error E00M__D_5 EX-CLOSE error E00M__C_2 Chuck-up error E00M__C_3 Unchucking error

3. Aging mode in Tape Deck section

1) Operation during aging mode

• In the agining mode, the program is excuted in the following sequence.

Step

Rewind the TAPE A

Rewind the TAPE B

Play the TAPE A (1 minute)

Stop the TAPE A (1 second)

Play the TAPE A (3 minutes)

Rewind(AMS) the TAPE A

F.F.(AMS) the TAPE A

Play the TAPE B (1 minute)

Stop the TAPE B (1 second)

Record the TAPE B (3 minutes)

Rewind(AMS) the TAPE B

F.F.(AMS) the TAPE B

Operation

Display

TAPE AAG-1 TAPE BAG-2 TAPE AAG-2 TAPE AAG-3 TAPE AAG-4 TAPE AAG-5 TAPE AAG-6 TAPE BAG-2 TAPE BAG-3 TAPE BAG-4 TAPE BAG-5 TAPE BAG-6

2) Error display

• If error occurred, the display remains like “TAPE BAG-2”.

4. Exiting from the aging mode

• Be sure to perform Cold Reset to exit from the aging mode.

HCD-GX20

[GC Test Mode]

• All fluorecent segments and LEDs are tested.

•Keyboard check.

Procedure:

1. Press ?/1 button to turn the set ON.

2. To enter the test mode, press the three b uttons x , GAME EQ and DISC 2 simultaneously.

3. All segments and LEDs (without STANDBY LED) are turned on.

4. Press GAME EQ and DISC 2 buttons simultaneously, and the key check mode is activated.

5. The message “KEY 0 0 0 0” is displayed. Each time a button is pressed, the key code number is displayed.

6. Press GAME EQ and DISC 2 buttons simultaneously, and the key count mode is activated.

7. The message “KEYCNT 0 1” is displayed. Each time a button is pressed, “KEYCNT 0 1” value increased. However, once a button is pressed, it is no longer taken into account.

8. Press GAME EQ and DISC 2 buttons simultaneously, and the head phone detect mode is activated.

9. The message “H_P OFF” is displayed when a headphone jack is not inserted. “H_P ON ” is displayed when a headphone jack is inserted.

10. Press GAME EQ and DISC 2 buttons simultaneously, and the volume control detect mode is activated.

11. The message “VOLUME FLAT” is displayed. “VOLUME UP” is displayed if rotating VOLUME knob clockwise, or “VOLUME DOWN” is displayed if rotating counterclockwise.

12. To exit from the GC test mode after the volume control detect mode, press GAME EQ and DISC 2 buttons simultaneously .

[MC Test Mode]

•This mode is used to test the function of the equalizer.

Procedure:

1. Press ?/1 button to turn the set ON.

2. To enter the test mode, press the three b uttons x , GAME EQ and DISC 3 simultaneously.

3. Press the MOVIE EQ button. The function of the equalizer is set to “MIN”.

4. Press the MUSIC EQ button. The function of the equalizer is set to “MAX”.

5. Press the P.FILE button. The function of the equalizer is set to “FLAT”.

6. To exit from this mode, press ?/1 button to turn the set OFF.

[CD Ship Mode (No Memory Clear) ]

•This mode moves the pickup to the position durable to vibra-

tion. Use this mode when returning the set to the customer after repair.

Procedure:

1. Press ?/1 button to turn the set ON.

2. Select the function “CD”.

3. Press ?/1 button to turn the set OFF.

4. Press CD button and ?/1 button simultaneously.

5. The "STANDBY" display blinks instantaneously, and the CD ship mode is set.

[Version and Destination Display Mode]

•The version or destination is displayed.

Procedure:

1. Press ?/1 button to turn the set ON.

2. To enter the test mode, press the three b uttons x , GAME EQ and MOVIE EQ simultaneously.

3. The destination is displayed.

4. Press STOP and GROOVE buttons simultaneously.

5. The version is displayed.

6. To exit from this mode, press ?/1 button to turn the set OFF.

[CD Service Mode]

•This mode can run the CD sled motor freely. Use this mode, for

instance, when cleaning the pickup.

Procedure:

1. Press ?/1 button to turn the set ON.

2. Select the function “CD”.

3. To enter the test mode, press three buttons x , GAME EQ , and OPEN/CLOSE simultaneously.

4. The CD service mode is selected.

5. With the CD in stop status, press to outside track, or press . button to inside track.

6. To exit from this mode, perform as follows:

> button to move the pickup

–

1) Move the pickup to the most inside track.

2) Press ?/1 button to turn the set OFF.

Note: • Always move the pickup to most inside track when exiting from

this mode. Otherwise, a disc will not be unloaded.

• Do not run the sled motor excessively, otherwise the gear can be chipped.

SECTION 4

AM RF Signal generator

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

AM ANTENNA terminal (JK103)

set

ELECTRICAL ADJUSTMENTS

HCD-GX20

TUNER SECTION

FM Tuned Level Adjustment

FM RF Signal generator

Ω

coaxial

set

Carrier frequency : 98 MHz Modulation : AUDIO 1 kHz, 75 kHz deviation (100%) Output level : 30 dB (at 75

Ω

open)

Procedure:

1. Supply a 98 MHz signal at 28 dB from the ANTENN A terminal.

2. Tune the set to 98 MHz.

3. Adjust RV101 to the point (moment) when the TUNED indicator will change from going off to going on.

Adjustment Location: MAIN board

Null Adjustment

FM RF Signal generator

Ω

coaxial

Carrier frequency : 98 MHz Modulation : AUDIO 1 kHz, 75 kHz deviation (100%) Output level : 60 dB (at 75

Ω

open)

FM ANTENNA terminal (JK103)

set

FM ANTENNA terminal (JK103)

AM IF Adjustment

level mete

Ω

set

headphones jack (JK691)

Procedure:

1. Set the frequency of the AM RF signal generator to 1000 kHz (at 10 kHz step) or 999 kHz (at 9 kHz step).

2. Tune the set to AM 1000 kHz (at 10 kHz step) or 999 kHz (at 9 kHz step).

3. Adjust IFT101 so that the reading on level meter becomes in maximum.

Procedure:

1. Supply a 98 MHz signal at 60 dB from the ANTENN A terminal.

2. Tune the set to 98 MHz.

3. Measure voltage between pin 21 and pin 23 of IC 101. Adjust

Adjustment Location: MAIN board

[MAIN BOARD] Component side

T101 until the voltage becomes 0 V.

T101: NULL

IFT101: AM IF

RV101: FM TUNED LEVEL

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