Jvc KS-FX945-R Service Manual

SERVICE MANUAL

CASSETTE RECEIVER

4987520036

KS-FX945R

SOUND

ATT

SOURCE

VOL

Area Suffix

EE --------- Russian Federation

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20

5 TROUBLE SHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24

6 DESCRIPTION OF MAJOR ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25

No.49875

2003/6

SPECIFICATION

AUDIO AMPLIFIER SECTION

TUNER SECTION Frequency Range FM1/FM2 87.5 MHz to 108.0 MHz

CASSETTE DECK SECTION

GENERAL Power Requirement Operating Voltage DC 14.4 V (11 V to 16 V allowance)

Design and specifications are subject to change without notice.

Maximum Power Output

Continuous Power Output (RMS)

Load Impedance 4 Ω (4 Ω to 8 Ω allowance) Tone Control Range Bass ±10 dB at 100 Hz

Frequency Response 40 Hz to 20 000 Hz Signal-to-Noise Ratio 70 dB Line-Out Level/Impedance 2.0 V/20 kΩ load (250 nWb/m) Output Impedance 1 kΩ

[FM Tuner] Usable Sensitivity 11.3 dBf (1.0 ΩV/75 Ω)

[MW Tuner] Sensitivity 20 µV

[LW Tuner] Sensitivity 50 µV Wow & Flutter 0.11% (WRMS) Fast-Wind Time 100 sec. (C-60) Frequency Response (Dolby B NR OFF) 30 Hz to 16 000 Hz (Normal tape) Signal-to-Noise Ratio 56 dB (Normal tape) (Dolby B NR ON) 65 dB (Dolby B NR OFF) 56 dB Stereo Separation 40 dB

Grounding System Negative ground Allowable Operating Temperature 0ºC to +40ºC Dimensions

(W ×H × D)

Front 50 W per channel Rear 50 W per channel Front 19 W per channel into 4 Ω 40 Hz to 20 000 Hz at

no more than 0.8% total harmonic distortion.

Rear 19 W per channel into 4 Ω 40 Hz to 20 000 Hz at

no more than 0.8% total harmonic distortion.

Treble ±10 dB at 10 kHz

FM3 65.00 MHz to 74.00 MHz AM (MW) 522 kHz to 1 620 kHz (LW) 144 kHz to 279

kHz

50 dB Quieting Sensitivity 16.3 dBf (1.8 ΩV/75 Ω) Alternate Channel Selectivity (400 kHz) 65 dB Frequency Response 40 Hz to 15 000 Hz Stereo Separation 30 dB Capture Ratio 1.5 dB

Selectivity 35 dB

Installation Size (approx.) 182 mm × 52 mm × 150 mm Panel Size (approx.) 188 mm × 58 mm × 12 mm Mass (approx.) 1.5 kg (excluding accessories)

1-2 (No.49875)

1.1 Safety Precautions

SECTION 1

PRECAUTION

Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system.

(No.49875)1-3

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

This service manual does not describe SPECIFIC SEVICE INSTRUCTIONS.

1-4 (No.49875)

SECTION 3

DISASSEMBLY

3.1 Main body

3.1.1 Removing the front panel assembly (See Fig.1)

(1) Press the release button and remove the front panel as-

sembly.

3.1.2 Removing the bottom cover (See Fig.2)

• Prior to performing the following procedures, remove the front

panel assembly. (1) Turn the main body upside down. (2) Insert a screwdriver under the joints to release the two

joints a on th e left side, two joints b on the right side and joint c on the back side of the main body, then remove the bottom cover from the main body.

CAUTION:

When releasing the joints using a screwdriver, do not damage the main board.

Front panel assembly

Release button

Fig.1

Front chassis assembly

Joint b

Joint a

3.1.3 Removing the front chassis assembly (See Figs.3 and 4)

• Prior to performing the following procedures, remove the front

panel assembly and bottom cover. (1) Remove the two screws A on the both sides of the main

body. (See Fig.3.)

(2) Remove the two screws B on the front side of the main

body. (See Fig.4.)

(3) Release the two joints d and two joints e on the both sides

of the main body, then remove the front chassis assembly toward the front. (See Fig.3.)

Joint a

Joint d

Joint c

Fig.2

Front chassis assembly

Fig.3

Front chassis assembly

Joint b

Joint e

Fig.4

(No.49875)1-5

3.1.4 Removing the heat sink (See Fig.5)

• Prior to performing the following procedure, remove the fro nt

panel assembly as required. (1) Remove the two screws C and screw D attaching the heat

sink on the left side of the main body, and remove the heat sink.

3.1.5 Removing the rear panel (See Fig.6)

• Prior to performing the following procedure, remove the fro nt

panel assembly and bottom cover. (1) Remove the two screws E, screw F and three screws G at-

taching the rear panel on the back side of the main body.

Heat sink

Rear bracket

Fig.5

3.1.6 Removing the main board (See Fig.7)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat sink and rear panel. (1) Remove the two screws H attaching the main board on the

top chassis.

(2) Disconnect the connector CP401 on the main board from

the cassette mechanism assembly.

Fig.6

Main board

CP401

Fig.7

1-6 (No.49875)

3.1.7 Removing the cassette mechanism assembly

(See Fig.8)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat sink, rear panel and main board. (1) Disconnect the wire from the connector CN402 on the

mecha board.

(2) Disconnect the card wire from the connector CN403 on the

mecha board.

(3) Remove the four screws J attaching th e cassette mecha-

nism assembly to the top chassis, take out the cassette mechanism assembly.

Cassette mechanism assembly

3.1.8 Removing the mecha bo ar d

(See Fig.9)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat sink, rear panel and main board. (1) Disconnect the wire from the connector CN402 on the

mecha board.

(2) Disconnect the card wire from the connector CN403 on the

mecha board. (3) Remove the screw K attaching the mecha board. (4) Bend the hook f in the direction of the arrow 1 and move the

mecha board in the direction of the arrow 2. (5) Remove the mecha board from the mecha bracket (L) of

the top chassis.

CN401

Top chassis

Fig.8

Mecha board

CN403

Fig.9

J J

CN402

hook f

(No.49875)1-7

3.1.9 Removing the front board (See Figs.10 to 12)

• Prior to performing the following procedures, remove the front

panel assembly. (1) Remove the four screws L attaching the rear cover on the

back side of the front panel assembly. (See Fig.10.)

(2) Release the nine joints g, the front panel assembly and

rear cover become separate. (See Fig.11.)

(3) Remove the front board from the front panel assembly.

(See Fig.12.)

Joints g

Front board

Joints g

Rear cover

Fig.10

Joints g

Rear cover

Fig.11

Front panel assembly

Fig.12

1-8 (No.49875)

3.2 Cassette mechanism assembly

REFERENCE:

Prior to performing the following procedures, turn the mode gear on the bottom of the body until the respective part comes to the EJECT position (Refer to Fig.1).

3.2.1 Removing the cassette guide

(See Fig.2)

(1) Turn the mode gear to set to RVS play or subsequent

mode.

(2) Remove the cassette guide from the main chassis while re-

leasing each two joint tabs a in the direction of the arrow.

Mode gea

Fig.1

Cassette guide

3.2.2 Removing the load arm

(See Fig.3)

(1) Remove the E-washer attaching the load arm. (2) Move the load arm in the direction of the arrow and release

the joint b on the cassette catch.

Load arm

E-washer

Tab a

Fig.2

Joint b

Fig.3

(No.49875)1-9

3.2.3 Removing the cassette hanger assembly / cassette holder

(See Fig.4 to 7)

(1) Check the mode is set to EJECT. Push down the front part

of the cassette holder and move in the direction of the arrow to release the joint c.

(2) Move the rear part of the cassette hanger assembly in the

direction of the arrow to release it from the two joint bosses d.

(3) Release the holder stabilizer spring fro m the hooks e and

f, then pull out from the cassette hanger assembly.

(4) Bring up the rear side of the cassette hanger asse mbly to

release the joint g and h.

(5) Pull out the cassette catch from the cassette hanger as-

sembly.

Cassette holder assembly

Side bracket

Joints c

Cassette holder assembly

Fig.4

Boss d

Cassette hanger assembly

Boss d

Cassette stabilizer spring

Hook e

Cassette holder assembly

Hook g

Cassette hange

assembly

Hook f

Fig.5

Cassette hanger assembly

Hook h

Fig.6

Cassette hanger assembly

1-10 (No.49875)

Cassette catch

Cassette holder assembly

Fig.7

3.2.4 Removing the side bracket assembly

(See Fig.8 to 10)

(1) Remove the screw A attaching the side bracket assembly. (2) Detach the front side of the side bracket assembly upward

and pull out forward to release the joint i and j in the rear.

CAUTION:

When reassembling, make sure that the boss k of the main chassis is set in the notch of the load rack under the side bracket assembly. Do not reattach the load rack on the boss k.

CAUTION:

After reattaching the side bracket assembly, confirm operation.

Side bracket assembly

Joint i

Joint j

Side bracket assembly

Fig.8

Side bracket assembly

Joint i

Joint j

Load rack

Boss k

Fig.9

Boss k

Fig.10

(No.49875)1-11

3.2.5 Removing the pinch arm (F) assembly

(See Fig.11 and 12)

(1) Remove the polywasher and pull out the pinch arm (F) as-

sembly.

(2) Remove the compulsion spring.

3.2.6 Removing the pinch arm (R) assembly (See Fig.11 and 12)

(1) Remove the polywasher and pull out the pinch arm (R) as-

sembly.

3.2.7 Removing the slide chassis assembly (See Fig.13 and 14)

REFERENCE:

It is not necessary to remove the head and the tape guide. (1) Move the slide chassis assembly in the direction of the ar-

row to release the two joints l and remove from the main chassis.

(2) Remove the rack link.

CAUTION:

When reassembling, first reattach the rack link, and next fit the boss m and hook n of the slide chassis assembly to the hole of the main chassis, and engage the two joints l.

Joint l

Slide chassis assembly

Fig.13

Head

Tape guide

Boss m

Rack link

Hook n

Polywasher

Compulsion spring

Pinch arm (R) assembly

Pinch arm (F) assembly

Fig.11

Pinch arm (F) assembly

Pinch arm (R) assembly

Polywashe

Fig.14

Polywasher

1-12 (No.49875)

Fig.12

3.2.8 Removing the head / tape guide

(See Fig.16 and 17)

REFERENCE:

It is not necessary to remove the slide chassis assembly. (1) Remove the band attaching the wire to the head. (2) Remove the two screws B, the head and the head support

spring. (3) Remove the pinch arm spring from the tape guide. (4) Remove the tape guide and the pinch spring arm.

CAUTION:

When reattaching the pinch arm spring, set both end of it to the pinch spring arm (remarked o).

CAUTION:

When reattaching the head, set the wires into the groove of the tape guide (Fig.16).

3.2.9 Removing the flywheel assembly (F) & (R) (See Fig.18 and 19)

REFERENCE:

It is not necessary to remove the slide chassis assembly. (1) Remove the belt at the bottom. (2) Remove the two polywashers on the upper side. (3) Pull out each flywheel assembly downward.

Slide chassis assembly

Flywheel assembly (F)

Flywheel assembly (R)

Belt

Fig.17

Polywasher

Head

Head support spring

Tape guide

Pinch spring arm

Head

Fig.15

Tape guide

Pinch arm spring

Flywheel assembly (F)

Flywheel assembly (R)

Fig.18

Slid chassis assembly

Fig.16

(No.49875)1-13

3.2.10 Disassembling the flywheel assembly (F)

(See Fig.19 and 20)

(1) Push and turn counterclockwise the spring holder (F) to re-

lease the three joints p on the bottom of the flywheel.

(2) The spring holder (F), the TU spring and the friction gear

play come off.

(3) Remove the polywasher and felt.

3.2.11 Disassembling the flywheel assembly (R) (See Fig.19 and 20)

(1) Push and turn clockwise the spring h older (R) to release

the three joints q on the bottom of the flywheel.

(2) The spring holder (R), the FF spring and the friction gear

FF come off.

(3) Remove the polywasher and the felt.

3.2.12 Removing the reel board (See Fig.21 and 22)

(1) Remove the two screws C attaching the reel board. (2) Move the reel board in the direction of the arrow to release

the joint r.

(3) Unsolder the wires if necessary.

CAUTION:

When reattaching, confirm operation of the MODE switch and the ST-BY switch.The mode position between EJECT and ST-BY is optimum for reattaching.Connect the card wire extending from the reel board to the FFC pad before reattaching the reel board.

FFC pad

Joint

Reel board

Fig.21

FFC pad

CT-1 switch

MODE switch

Flywheel assembly (F)

Joint p

Joints p

Fig.19

Polywasher

Spring holder (R)

Spring holder (F)

TU spring

Friction gear FF

Friction gear play

Polywasher

FF spring

Flywheel assembly (R)

Joints q

Joint q

Soldering

ST-BY switch

Fig.22

Flywheel assembly (F)

1-14 (No.49875)

Felt

Flywheel assembly (R)

Fig.20

3.2.13 Removing the gear base arm / gear base link assembly

(See Fig.23 to 25)

(1) Move the gear base arm in the direction of the arrow. (2) Insert a slotted screwdriver to the gear base spring under

the gear base arm, and release the gear base arm upward from the boss on the gear base assembly.

(3) Remove the gear base arm from the main chassis while re-

leasing the two joints s.

(4) Move the gear base link assemby in the direction of the ar-

row to release the two joints t.

REFERENCE:

When reattaching the gear base arm, make sure that the boss on the gear base assembly is inside the gear base spring.

3.2.14 Removing the FFC pad

(See Fig.25 and 27)

(1) Push each joint hook u of the FFC pad and remove toward

the bottom.

Gear base link assembly

Gear base spring

Joint t

Gear base arm

Joints s

Hook u

FFC pad

Hook u

Joint t

Fig.23

Gear base arm

Gear base link assembly

Screwdriver

Fig.24

Gear base arm

FFC pad

Fig.25

(No.49875)1-15

3.2.15 Removing the mode gear

(See Fig.26 and 29)

(1) Remove the polywasher on the bottom and pull out the

mode gear.

3.2.16 Removing the mode switch actuator (See Fig.26, 27 and 29)

(1) Pull out the mode switch actuator at the bottom.

REFERENCE:

When reattaching the mode switch actuator to the main chassis, make sure to set on the shaft and insert v into the slot w.

3.2.17 Removing the direction link / direction plate (See Fig.27 to 29)

(1) Remove the polywasher attaching the direction link. (2) Bring up the direction link to release the thre e joints x, y

and z at a time.

(3) Move the direction plate in the direction of the arrow to re-

lease the two joints a’.

REFERENCE:

When reattaching the direction plate, engage the two joints a’ and move in the direction of the arrow (Refer to Fig.28).

REFERENCE:

When reattaching the direction link, move the direction plate in the direction of the arrow and engage the three joint x, y and z at a time (Refer to Fig.29).

3.2.18 Removing the mode rack assembly (See Fig.27 and 28)

(1) Move the mode rack assembly in the direction of the arrow

to release the two joints b’ and the joint c’.

REFERENCE:

When reattaching, set the two b’ on the bottom of the mode rack assembly into the slots of the main chassis and move in the direction of the arrow (See Fig.28).

Direction plate

Joints a'

Joint z

Direction link

Direction plate

Mode switch actuator

Direction link

Fig.26

Slot w

Joint y

Polywasher

Fig.27

Mode rack assembly

Joint b'

Mode gear

Polywashe

Mode rack assembly

Joint x

Joint b'

Joint c'

1-16 (No.49875)

Joints a'

Fig.28

Direction link

Mode switch actuator

Polywasher

Mode gea

Direction plate

Mode rack assembly

Fig.29

3.2.19 Removing the gear base assembly / take up gear / reflector gear

(See Fig.30 to 32)

(1) Push in the pin d’ of the gear base assembly on the upper

side of the body and move the reflector gear toward the bottom, then pull out.

(2) Remove the polywasher on the bottom and pull out the

take up gear.

(3) Move the gear base assembly in the direction o f the arrow

to release it from the two slots e’ of the main chassis.

REFERENCE:

The parts are damaged when removed. Please replace with new ones.

3.2.20 Removing the reel driver / reel spindle

(See Fig.32)

(1) Draw out the reel driver from the shaft on the main chassis

and remove the reel driver spring and the reel spindle respectively.

CAUTION:

The reel driver is damaged when remo ved. Please replace with a new one.

Gear base assembly

Pin d'

Polywasher

Slot e'

Fig.30

Take up gear

Reflector gear

Reel driver

Reel driver spring

Reel spindle

Main chassis

Reflector gear

Fig.31

Reel driver

Reel driver spring

Reel spindle

Gear base assembly

Slots e’

Take up gea

Polywasher

Fig.32

(No.49875)1-17

3.2.21 Removing the side bracket assembly (See Fig.33 to 37)

(1) Remove the eject cam plate spring. (2) Push the joint f’ through the slot to remove the load rack

downward.

(3) Move the eject cam limiter in the direction of the arrow to

release it from the boss g’ of the side bracket assembly and from the two joints h’.

(4) Move the eject cam plate in the direction of the arrow to re-

lease the joint i’.

CAUTION:

When reassembling, confirm operation of each part before reattaching the eject cam plate spring.

Joint f'

Side bracket assembly

Boss g'

Eject cam plate

Fig.36

Side bracket assembly

Joint i'

Eject cam plate spring

Side bracket assembly

Joint h'

Side bracket assembly

Boss g'

Load rack

Fig.33

Eject cam limiter

Joint f'

Fig.34

Eject cam limiter

Eject cam plate

Joint i'

Fig.37

Joint h'

Load rack

Joint h'

1-18 (No.49875)

Eject cam plate

Fig.35

Joint h'

3.2.22 Removing the main motor assembly / sub motor assembly

r r

(See Fig.38 to 40)

(1) Remove the belt at the bottom. (2) Remove the polywasher and pull out the mode gear. (3) Pull out the reduction gear (B). (4) Remove the polywasher and pull ou t the reduction gear

(A).

(5) Remove the two screws attaching the main motor assem-

bly.

(6) Remove the two screws E attaching the sub motor assem-

bly.

(7) Unsolder the wires on the reel board if necessary.

CAUTION:

When reassembling, adjust the length of the wires extending from the sub motor asswmbly by attaching them to the side of the sub motor assembly with the wires extending from the main motor assembly using a spacer.

Belt

Reduction gear (B)

Mode gear

Polywasher

Fig.38

Main motor

assembly

Reduction gear (A)

Polywashe

Sub moto assembly

Polywasher

Reduction gear (A)

Spacer

Main motor assembly

Sub motor assembly

Fig.39

Main motor assembly

Sub motor assembly

Fig.40

Space

(No.49875)1-19

SECTION 4

ADJUSTMENT

4.1 Adjustment method

 Test instruments required for adjustment

(1) Digital oscilloscope (100MHz) (2) Frequency counter meter (3) Electric voltmeter (4) Wow & flutter meter (5) Test tapes

• VT724...........................For DOLBY level measurement

• VT739..............For playback frequency measurement

• VT712....For wow flutter & tape speed measurement

• VT703........................For head azimuth measurement

(6) Torque gauge............................Cassette type for CTG-N

 Measuring conditions (Amplifier section)

• Power supply voltage.............. DC14.4V (11V to 16V allowance)

• Load impedance............ 4Ω (4Ω to 8Ω allowance)

• Line out level/Impedance..............1.0V/20k load (250 nWb/m)

 Standard volume position

Balance and Bass, Treble volume, Fader : Center (Indication "0") Loudness, Dolby NR, Sound, Cruise : Off Volume position is about 2V at speaker output with following conditions, Playback the test tape VT721.

AM mode 999kHz/62dB, INT/400Hz, 30%

modulation signal on receiving.

FM mono mode 97.9MHz/66dB, INT/400Hz, 22.5kHz

deviation pilot off mono FM stereo mode 1kHz, 67.5kHz dev. pilot 7.5kHz dev. Output level 0dB (1µV,50Ω/open terminal)

1-20 (No.49875)

 Information for using a car audio service jig

(1) We're advancing efforts to make our extension cords common for all car audio products.

Please use this type of extension cord as follows.

(2) As a U-shape type top cover is employed, this type of extension cord is needed to check operation of the mechanism assembly

after disassembly. (3) Extension cord : EXTKSRT002-18P ( 18 pin extension cord ) For connection between mechanism assemblyand main board. (4) Check for mechanism driving section such as motor ,etc.

 Disassembly method

(1) Remove the front panel assembly. (2) Remove the bottom cover. (3) Remove the front chassis. (4) Remove the heat sink. (5) Remove the rear panel (6) Remove the main board. (7) Reattach the heat sink with the two screws B. (Refer to Disassembly method.) (8) Reattach the rear panel with the screw E. (Refer to Disassembly method.) (9) Reattach the front panel assembly.

(10) Confirm that current is being carried by connecting an extension cord ji g.

NOTE:

Available to connect to the CJ601

CAUTION :

Be sure to attach the heat sink and rear pa nel on the power ampl ifier IC and regulator I C of a main board when su pplying the power.If voltage is applied without attaching those parts, the power amplifier IC and regulator IC will be destroyed by heat.

connector when installing the front panel.

Cassette mechanism

EXTKSRT002-18P

Extension cord EXTKSRT002-18P

To Main board

Front panel assembly

Cassette mechanism

Main board

(No.49875)1-21

 Arrangement of adjusting & test points

Cassette mechanism

(Surface)

Motor assembly

Tape speed adjust

Azimuth screw

(Forward)

Playback head

Azimuth screw B

(Reverse)

Head section view

Azimuth screw B

(Reverse)

Playback head

Azimuth screw A

(Forward)

1-22 (No.49875)

Item Conditions Adjustment and Confirmation methods S.Values Adjust

1. Head azimuth adjustment

Test tape: SCC-1659 VT703 (10kHz)

Head height adjustment

Adjust the azimuth directly. When you adjust the height using a mirror tape, remove the cassette housing from the mechanism chassis. After installing the cassette housing, perform the azimuth adjustment. (1) Load the SCC-1659 mirror tape. Adjust with height

adjustment screw A and azimuth adjustment screw B so that line A of the mirror tape runs in the center between Lch and Rch in the reverse play mode.

(2) After switching from REV to FWD then to REV,

check that the head position set in procedure 1 is not changed. (If the position has shifted, adjust again and check.)

(3) Adjust with azimuth adjustment screw B so that line

B of the mirror tape runs in the center between Lch and Rch in the forward play mode.

Head shield

The head is at low position during.

Head shield

The head is at High position during REV.

A line

B line

2. Tape speed and wow flutter confirmation

3. Play back frequency response confirmation

Test tape: VT724 (1kHz) VT703 (10kHz) VT721 (315Hz)

Test tape: VT712 (3kHz)

Test tape: VT724 (1kHz) VT739 (63Hz / 1kHz / 10kHz)

Head azimuth adjustment

(1) Load VT724 (1kHz) and play it back in the reverse

play mode. Set the Rch output level to max.

(2) Load VT703 (10kHz) and play it ba ck in the fo rward

play mode. Adjust the Rch and Lch output levels to max, with azimuth adjustment screw B. In this case, the phase difference should be within 45 .

(3) Engage the reverse mode and adjust the output lev-

el to max, with azimuth adjustment screw C.(The phase difference should be 45 or more.)

(4) When switching between forward and reverse

modes, the difference between channels should be within 3dB. (Between FWD L and R, REV L and R.)

(5) When VT721 (315Hz) is played back, the level differ-

ence between channels should be within 1.5dB.

(1) Check to see if the reading of the F, counter / wow

flutter meter is within 3015Hz to 3045Hz (FWD/ REV), and less than 0.35% (JIS RMS).

(2) In case of out of specification, adjust the motor with

a built-in volume resistor.

(1) Play test tape VT724, and set the volume position at

2V.

(2) Play test tape VT739 and confirm.1kHz / 10kHz: -1

±3dB,1kHz / 63Hz: 0 ±3dB,

(3) When 10kHz is out of specification, it will be neces-

sary to read adjust the azimuth.

Output level: Maximum

PBHead

FWD Adj B

REV Adj C

(0 ) (45 )

Tape speed: 3015Hz to 3045Hz Wow flutter: less than 0.35%

Speaker out 1kHz / 63Hz: 0 ±3dB 1kHz / 10kHz: -1 ±3dB

HEIGHT Adj A

phase

Built-in volume resistor

The tuner section is of an adjustment-freedesign. In case the tuner is in trouble, replace the tuner pack.

(No.49875)1-23

SECTION 5

TROUBLE SHOOTING

This service manual does not describe TROUBLE SHOOTING.

1-24 (No.49875)

SECTION 6

DESCRIPTION OF MAJOR ICs

6.1 BR24L16F-W-X (IC771) : EEPROM

•Pin layout •Pin function

VCC WP SCL SDA

A0 A1 A2 GND

• Block diagram

Symbol I/O Function

VCC - Power supply.

GND - GND

A0,A1,A2 I No use conn ect to GND.

SCL I Serial clock input.

SDA I/O Serial data I/O of slave and ward address.

WP I Write protect terminal.

A0 1

11bit

A1 2

A2 3

GND 4

High voltage osc circuit

Address

decoder

6.2 IC-PST600M/G/-W (IC702) : System reset

Co1

16kbit EEPROM allay

11bit

START

Control circuit

Slave Ward

Address resister

STOP

Power supply voltage det.

OP1

ACK

8bit

Data

resister

8 Vcc

7 WP

6 SCL

5 SD

Vout

6.3 LB1641 (IC402) : DC Motor driver

•Pin layout •Truth table Input Output Mode

IN1 IN2 OUT1 OUT2

0000 Brake

1 2 3 4 5 6 7 8 9

GND OUT1 P1

VZ IN1 IN2

VCC1

VCC2 P2

OUT2

1 0 1 0 CLOCKWISE 0 1 0 1 COUNTER-CLOCKWISE 1100 Brake

GND

(No.49875)1-25

6.4 CXA2560Q (IC4 01) : Dolby B typ e no ise reduction system with play back equalizer amp.

• Pin layout & block diagram

PBFB2

PBRIN2

PBGND

PBFIN2

VCT

PBREF

PBFIN1

PBGND

PBRIN1

PBFB1

PBTC2

30 29 28

7k/12k

45k

12345

PBTC1

300k

30k

300k

7k/12k

PBOUT2

PBOUT1

OUTREF2

TAPEIN2

100k

70 /120

100k

70 /120

TAPEIN1

OUTREF1

GND

Vcc

DIREF

BIAS

MUTE

TAPE EQ

FWD/RVS

Vcc

LPF

LINEOUT2

23 22 21

OFF/B

LINEOUT1

TCH2

MSSW

MS MODE

NR MODE

MS ON/

OFF

DET

8910

TCH1

MSLPF

• Pin function Pin No. Symbol I/O Function

1 PBTC1 - Playback equalize r ampl ifier

capacitance

2 PBOUT1 O Playback equalizer amplifier

output 3 OUTREF1 O Output reference 4 TAPEIN1 I TAPE input 5 Vcc - Power su pply 6NC7 LINEOUT1 O Line output 8 TCH1 - Time constant for the HLS 9NC-

10 MSLPF - Cut-off frequency adjustment

of the music sensor LPF

11 G2FB - Music signal interval detection 12 G1FB - Music signal interval detection 13 MSTC - Time constant for detecting

music signal interval

14 MSOUT O Music sensor out 15 NC - No use 16 NRSW I Dolby NR control 17 MUTESW I Mute function control 18 TAPESW I Playback equalizer amplifier

control

19 DRSW I Head select control 20 MSMODE I Music sensor mode control 21 MSSW I Music sensor control 22 NC 23 TCH2 - Time constant for the HLS

MSMODE

DRSW

TAPESW

MUTESW

NRSW

MSOUT

MSTC

G1FB

G2FB

Pin No. Symbol I/O Function

24 LINEOUT2 O Line output 25 DIREF - Resistance for setting the

reference 26 GND - Ground 27 TAPEIN2 I TAPE input 28 OUTREF2 O Output reference 29 PBOUT2 O Playback equalizer amplifier

output 30 PBTC2 - Playback equalizer amplifier

capacitance 31 PBFB2 I Playback equalizer amplifier

feedback 32 PBRIN2 I Playback equalizer amplifier

input 33 PBGND - Playback equalizer amplifier

ground 34 PBFIN2 I Playback equalizer amplifier

input 35 VCT O Center 36 PBREF O Playback equalizer amplifier

reference 37 PBFIN1 I Playback equalizer amplifier

input 38 PBGND - Playback equalizer amplifier

ground 39 PBRIN1 I Playback equalizer amplifier

input 40 PBFB1 I Playback equalizer amplifier

feedback

1-26 (No.49875)

6.5 HA13164A (IC901) : Regulator

• Terminal layout

123456789101112131415

• Block diagram

ANT OUT

EXT OUT

ANT CTRL

CTRL

CD OUT

AUDIO OUT

0.1u

10u

VCC ACC

Surge Protector

BIAS TSD

TAB

100u

0.1u

ILM AJGND GND

ACC

BATT.DET OUT

COMPOUT

VDD OUT

SW5VOUT

ILMOUT

0.1u

UNIT R:

C:F

note1) TAB (header of IC)

connected to GND

• Pin function Pin No. Symbol Function

1 EXTOUT Output voltage is VCC-1 V when M or H level applied to CTRL pin. 2 ANTOUT Output voltage is VCC-1 V when M or H level to CTRL pin and H level to ANT-CTRL. 3 ACCIN Connected to ACC. 4 VDDOUT Regular 5.7V. 5 SW5VOUT Output voltage is 5V when M or H level applied to CTRL pin. 6 COMPOUT Output for ACC detector. 7 ANT CTRL L:ANT output OFF H:ANT output ON 8 VCC Connected to VCC.

9 BATT DET Low battery detect. 10 AUDIO OUT Output voltage is 9V when M or H level applied to CTRL pin. 11 CTRL L:BIAS OFF M:BIAS ON H:CD ON 12 CD OUT Output voltage is 8V when H level applied to CTRL pin. 13 ILM AJ Adjustment pin for ILM output voltage. 14 ILM OUT Output voltage is 10V when M or H level applied to CTRL pin. 15 GND Connected to GND.

(No.49875)1-27

6.6 HD74HC126FP-X (IC801) : Buffer

• Pin layout • Pin function Input Output

CA Y LX Z HL H HH L

Note:

H:High level L:Low level X:Irrelevant Z:Off(High-impedance) State a 3-state input

• Block diagram

GND

1 2 3 4 5 6 7

14 13 12 11 10

9 8

VCC

Vcc Vcc

Input

Note:

CL includes probe and jig capacitance

See Function Table

1A 2A 3A 4A 1C 2C 3C 4C

Output

Sample as Load Circuit 1

1-28 (No.49875)

6.7 LC75873NW (IC601):LCD Driver

•Pin layout

60 41

1 20

• Block diagram

S4/P4

S3/P3

S2/P2

S62

S66

SEGMENT DRIVER

SHIFT REGISTOR

ADDRESS

DETECTOR

• Pin function

VDD1

VDD2

INH

OSC

VDD

VSS

COM2

COM3

COMON DRIVER

CLOCK

GENERATOR

COM1

Pin No. Pin name I/O Description

79,80

1,2,3

S1/P1 to S4/P4

S5 to S68

O Segment outouts for displaying the display data transferred by serial data input.

The S1/P1 to S4/P4 pins can be used as generalpurpose output ports under serial data control.

to 66

67 78 69

COM1 COM2 COM3

O Common drive r ou tp u ts.

The frame frequency f0 is given by : f0 = (FOSC/384)Hz.

74 OSC I/O Oscillator connection

An oscillator circuit is formed by connecting an external resistor and capacitor to this pin.

76 77 78

CE CL

Serial data transfer inputs.

Connected to the controller.

CE:Chip enable CL:Synchronization clock DI:Transfer data

75 INH

I Display off control input

•INH

= "L"(VSS) ---Display forced off S1/P1 to S4/P4 = "L" (These pins are forcibly set to the segment output port function and held at the low level.) S5 to S68 = "L" COM1 to COM3"L"

= "H"(HDD)---Display on

•INH However, serial data transfer is possible when the display is forced off by this pin.

71 VDD1 I Used for applying the LCD drive 2/3 bias voltage externally. Must be connected to VDD2 when a 1/2

bias drive scheme is used.

72 VDD2 I Used for applying the LCD drive 1/3 bias voltage externally. Must be connected to VDD1 when a 1/2

bias drive scheme is used. 70 VDD - Power supply connection. Provide a voltage of between 3.0 and 6.0V. 73 VSS - Power supply connection. Connect to ground.

S1/P1

(No.49875)1-29

6.8 LA47505 (IC 301) : Power amp.

• Terminal layout

206

Protective

circuit

Stand by

Switch

Ripple

Filter

Mute

circuit

Muting &

On Time Control

Circuit

protective

circuit

1-30 (No.49875)

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