JVC MXGT-700 Service manual

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MX-GT700

Area suffix

J ------------------- U.S.A. C ---------------- Canada

MX-GT700

STANDBY/ON

12

3

SUBWOOFER

L

EVE

FM/A M

RM–SMXG500A REMOT

456

78

10

T

APE

CD

L

S

O

UND O

DE

M

9

FM MODE

+10

FADE

T

APE A/B

MUTIN

G

DISC SKIP

+

VOL

UME

VOL

UME

–

E CONTROL

SLEEP

AUX

SP-MXGT700

Contents

Safety Precautions Importance administering point on the safety Preventing static electricity Disassembly method Wiring connection Adjustment method

STANDB

Y

STANDBY/ON

EXTENDED SUPER BASS

FM

CD

AUX

/ AM

PROGRAMRANDO

R

EPEAT

PHONES

REC STAR

T

C

D REC

/STO

P

START

FULL - LOGIC CONTROL

CA-MXGT700

1-2

1-3 1-4 1-5 1-18 1-19

M

DUBBING

DISC CHANGE

1

2

3

D

C

3

MX-GT700

T

APE

A

COMPU PLAY CONTROL

CD

TAPE BTAPE

CLOCK /TIMER

DISPLAY

TUNING

SUBWOOFER

LEVEL

CD SYNCHRO RECORDIN

SOUND

G

CD-R/RW PLAYBACK

M

ODE

SP-MXGT700

Flow of functional operation until TOC read Maintenance of laser pickup Replacement of laser pickup Trouble shooting Description of major ICs

1-23 1-24 1-24 1-25 1-28~41

No.21079

Apr. 2002

MX-GT700

1. This design of this product contains special hardware and many circuits and components specially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services should be performed by qualified personnel only.

2. Alterations of the design or circuitr y of the product should not be made. Any design alterations of the product should not be made. Any design alterations or additions will void the manufacturer`s warranty and will further relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.

3. Many electrical and mechanical parts in the products have special safety-related characteristics. These

characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in the Parts List of Service Manual. Electrical components having such features are identified by shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the same safety characteristics as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or other hazards.

4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of electric shock and fire hazard. When service is required, the original lead routing and dress should be observed, and it should be confirmed that they have been returned to normal, after re-assembling.

5. Leakage currnet check (Electrical shock hazard testing) After re-assembling the product, always perform an isolation check on the exposed metal parts of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock. Do not use a line isolation transformer during this check.

Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure the leakage current from each exposed metal parts of the cabinet, particularly any exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.).

Alternate check method Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15 F AC-type capacitor between an exposed metal part and a known good earth ground. Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each exposed metal part, particularly any exposed metal part having a return path to the chassis, and meausre the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Voltage measured any must not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).

0.15 F AC TYPE

1500 10W

Good earth ground

AC VOLTMETER (Having 1000 ohms/volts, or more sensitivity)

Place this probe on each exposed metal part.

!

1. This equipment has been designed and manufactured to meet international safety standards.

2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.

3. Repairs m ust be made in accordance with the relevant safety standards.

4. It is essential that safety critical components are replaced by approved parts.

5. If mains voltage selector is provided, check setting for local v oltage.

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.

In regard with component parts appearing on the silk-screen pr inted side (parts side) of the PWB diagrams, the parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the " " mark nearby are critical for safety.

(This regulation does not correspond to J and C version.)

1-2

Importance administering point on the safety

MX-GT700

RFS9

4A 125V

RFS2

Fuse board (Forward side) Power supply board (Forward side)

Caution: For continued protection against risk of fire, replace only with same type 4A/125V for RFS2 and RFS9. This symbol specifies type of fast operating fuse.

Precaution: Pour eviter risques de feux, remplacez le fusible de surete de et RFS2 et RFS9 comme le meme type que 4A/125V. Ce sont des fusibles suretes qui functionnes rapide.

^

1-3

MX-GT700

Preventing static electricity

1. Grounding to prevent damage by static electricity

Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.

2. About the earth processing for the destruction prevention by static electricity

In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity of the work environment. Be careful to use proper grounding in the area where repairs are being performed.

2-1 Ground the workbench

Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it.

2-2 Ground yourself

Use an anti-static wrist strap to release any static electricity built up in your body.

(caption) Anti-static wrist strap

Conductive material (conductive sheet) or iron plate

3. Handling the optical pickup

1. In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.)

2. Do not use a tester to check the condition of the laser diode in the optical pickup. The tester's internal power source can easily destroy the laser diode.

4. Handling the traverse unit (optical pickup)

1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.

2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a time when attaching it to the connector.

3. Handle the flexible cable carefully as it may break when subjected to strong force.

4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it

Attention when CD mechanism assembly is decomposed

*Please refer to "Disassembly method" in the text for pick-up and how to detach the CD mechanism assembly.

1. Remove the CD changer unit.

2. Remove the CD changer mechanism.

3. Solder is put up before the card wire is removed from the pickup unit connector on the CD mechanism assembly. (When the card wire is removed without putting up solder, the CD pick-up assembly might destroy.)

4. Please remove solder after connecting the card wire with the pickup unit connector when you install picking up in the substrate.

Card wire

Picup unit connector

Soldering

Fig.2

CD changer unit

Fig.1

Card wire

Picup unit connector

CD changer mechanism

1-4

MX-GT700

Disassembly method

Removing the metal cover (See Fig.1)

1.

Remove the three screws A attaching the metal cover on the back of the body.

2.

Remove the six screws B attaching the metal cover on the both sides of the body.

3.

Remove the metal cover from the body by lifting the rear part of the cover.

ONE POINT

How to eject the CD tray (see fig.2)

Although it will end if the OPEN/CLOSE button is pushed when a power supply can be taken, when that is not right, CD tray will be opened manually. Turn the loading pulley gear at the bottom of the CD changer unit as shown in Fig.2 and draw the CD tray toward the front.

Metal cover

A

B

(both sides)

Fig.1

Loading pulley gear (See <CD changer unit>fig.1)

Removing the CD Tray fitting

(See Fig. 3)

Prior to performing the following procedure, eject the CD tray.

After drawing the lower part of the tray fitting toward

1. the front, remove the five claws. Then, while moving the tray fitting upward, remove it.

Removing the CD changer unit

(See Fig.4 to 7)

Prior to performing the following procedure, remove the metal cover.

1.

Remove the card wire attached to CD changer unit on the adhesion tape.

2.

Disconnect the card wire from the connector CW107 on the CD servo board.

3.

Disconnect the harness from the connector RCW6 on the main board and CW105 on the CD servo board.

4.

Remove the two screws C attaching the CD changer unit to the rear panel.

Fig.2

Joint

CD tray fitting

Claw

Fig.3

Card wire

CD changer unit

5.

Remove the two screws D attaching the CD changer unit to the both side of front panel assembly.

6.

Draw the CD changer unit upward from behind while pulling the rear panel outward.

Adhesion tape

Fig.4

1-5

MX-GT700

CW105 CW107

Fig.5

CD servo board

CD changer unit

Main board

RCW6

Front panel

assembly

D

(both sides)

C

Rear panel

Fig.6

CD changer unit

Rear panel

Fig.7

Removing the front panel assembly

(See Fig.8 to 10)

Prior to performing the following procedure, remove the metal cover and the CD changer unit.

1.

Disconnect the card wire from the connector FCW3 on the main board.

2.

Disconnect the harness from the connector JCW1, JCW2 and HCW3 on the main board.

3.

Remove the two screws E attaching the front panel assembly to both sides of the body.

4.

Remove the screw F attaching the earth terminal extending from the cassette mechanism assembly.

5.

Remove the screw G attaching the main board to front panel assembly.

6.

Remove the screw H attaching the front panel assembly to the bottom of the body.

7.

Release the two joints1 and two joints2, and detach the front panel assembly toward the front.

Front panel

assembly

Joint1 (both sides)

(both sides)

E

FCW3

JCW2

Fig.8

Main board

JCW1

HCW3

F

(fixing the earth wire)

ACW6

Main board

ACW1

ACW2

Amp. board

ACW5

Front panel assembly

G

1-6

Fig.9

Joint1 (both sides)

E

(both sides)

MX-GT700

Removing the heat sink & amp. board

(See Fig.8, 11 and 12)

Prior to performing the following procedure, remove the metal cover and the CD changer unit.

1.

Disconnect the card wire from the connector ACW1 and the harness from the connector ACW2 and ACW6 on the amp. board.

2.

Remove the four screws I attaching the heat sink cover to the rear panel. Remove the heat sink cover.

3.

Remove the four screws J attaching the heat sink and two screws K attaching the speaker terminal to the rear panel.

4.

After moving the heat sink upward, remove the claws. Then pull out the heat sink & amp. board inward.

H

Heat sink

cover

Joint2

Fig.10

(Bottom side)

Rear panel

I

Removing the fan motor (See Fig.8 and 12)

Prior to performing the following procedure, remove the metal cover and heat sink cover.

1.

Disconnect the harness from the connector ACW5 on the amp. board.

2.

Remove the two screws L attaching the fan motor to the rear panel.

Removing the tuner board (See Fig.12 and 13)

Prior to performing the following procedure, remove the metal cover.

1.

Disconnect the card wire from the connector CON01 on the tuner board.

2.

Remove the two screws M attaching the tuner board to the rear panel.

J

Fan motor

Heat sink

J

O

Main board

Fig.11

L

Rear panel

M

N

K

Speaker terminal

Fig.12

Rear panel

CON01

Removing the rear panel (See Fig.12)

Prior to performing the following procedure, remove the metal cover, CD changer unit, heat sink & amp. board and tuner board.

1.

Remove the two screws N and three screws O attaching the rear panel.

Tuner board

Fig.13

1-7

MX-GT700

Removing the main board (See Fig. 14)

Prior to performing the following procedure, remove the metal cover, CD changer unit and rear panel.

1.

Disconnect the card wire from the connector FCW3 and the harness from the connector JCW1, JCW2 and HCW3 on the main board.

2.

Disconnect the harness from the connector PCW1 on the fuse board.

3.

Remove the screw G attaching the main board holder to the front panel assembly. (See Fig.9)

4.

Remove the two screws P attaching the heat sink to bottom chassis.

Removing the power cord (See Fig. 14)

Prior to performing the following procedure, remove the metal cover, CD changer unit and rear panel.

1.

Disconnect the power cord from the connector RCW2 on the power supply board and pull up the power cord stopper upward.

Fuse board

PCW1

Power supply

board

RCW2

Power cord Power cord

stopper

Bottom chassis

Fig.14

Q

FCW3

JCW2

JCW1

Main board

HCW3

Heat sink

P

Heat sink

Removing the power ICs

(See Fig.15 and 16)

Prior to performing the following procedure, remove the metal cover, CD changer unit and heat sink & amp. board.

1.

Remove the four screws Q attaching the power ICs to the heat sink.

2.

Unsolder the power ICs solder point.

Removing the power transformer

(See Fig .17)

Prior to performing the following procedure, remove the metal cover, CD changer unit and heat sink & amp. board.

1.

Disconnect the power cord from the connector RCW2 on the power supply board.

2.

Disconnect the harness from the connector PCW1 on the fuse board.

Power ICs solder point

R

Bottom chassis

Fig.15

Heat sink

Fig.16

Power transformer

Amp. board

Amp. board (reverse side)

PCW1

Fuse board

S

Power supply

board

RCW2

3.

Remove the four screws R attaching the power transformer and the screw S attaching the earth terminal on the bottom chassis.

1-8

Fig.17

MX-GT700

)

Prior to performing the following procedure, remove the metal cover, the CD changer unit and the front panel assembly.

Removing the power / CD switch board (See Fig.1)

1.

Disconnect the card wire from the connector UCW1 on the power / CD switch board.

2.

Remove the five screws A attaching the power / CD switch board.

Removing the FL display & system control board (See Fig.1)

1.

Disconnect the card wire from the connector UCW3, UCW4, UCW5 and UCW6 on the FL display & system control board.

2.

Remove the six screws B attaching the FL display & system control board.

3.

Disconnect the card wire from the connector UCW2 on the FL display & system control board.

B

UCW2 UCW3

B

UCW4

Front panel assembly (inner side

A

Power / CD switch board

Fig.1

Sound mode knob

Volume knob

FL display & system control board

UCW1

UCW5 UCW6

Removing the headphone jack board (See Fig.3)

Prior to performing the following procedure remove the FL display & system control board.

1.

You can pull out the headphone jack board.

Removing the front key switch board

(See Fig.2 and 3)

Prior to performing the following procedure, remove the FL display & system control board.

1.

Pull out the sound mode knob, volume knob and subwoofer level knob from front side.

2.

Remove the twelve screws C attaching the front key switch board.

3.

Remove the front board releasing the two tabs.

4.

Disconnect the card wire from the connector UCW7 on the front key switch board, if needed.

Removing the cassette mechanism assembly (See Fig.3)

C

UCW7

Tab

Mecha.

board

C D

Subwoofer level knob

Fig.2

Front panel assembly (inner side

Front key switch board

Headphone

jack board

D

1.

Disconnect the card wire from the connector on the mecha. board.

2.

Remove the six screws D attaching the cassette mechanism assembly.

D

(fixing the earth wire)

Connector

Cassette mechanism

assembly

Fig.3

1-9

MX-GT700

Prior to performing the following procedure, remove the CD changer unit.

Removing the CD tray (See Fig.1 to 3)

1.

Turn the black loading pulley gear on the under side of the CD changer unit in the direction of the arrow and draw the CD tray toward the front until it stops.

2.

Disconnect the card wire from connector CW103 on the CD servo board.

3.

Push down the two tray stoppers marked a and pull out the CD tray.

CD changer uint (reverse side)

CD servo board

CW103

Loading pulley gear

CD tray

Fig.1

CD tray

Reinstall the CD tray (See Fig.4 and 5)

1.

Align the gear-cam with the gear-tray as shown fig.4, then mount the CD tray.

2.

When assembling the CD tray, take extreme care not engage with gear - synchro.

Gear-cam

Gear-tray

CD tray

(Tray stopper)

Fig.2

a (Tray stopper)

a

CW103 (on the CD servo board)

Fig.3

Gear-convert

1-10

Gear-tray

Gear-cam

timing point

Gear-tray

CD tray

Fig.4 Fig.5

Gear-synchro

Removing the CD mechanism holder assembly (mechanism included)

(See Fig.11 to 14)

1.

Disconnect the harness from connector on the CD mechanism board in the CD mechanism assembly on the under side of the CD changer unit. Disconnect the card wire from the pickup unit connector.

Attention : Solder is put up before the card wire is removed from the pick-up unit connector on the CD mechanism assembly. (Refer to Fig.10) (When the card wire is removed without putting up solder, the CD pick-up unit assembly might destroy.)

MX-GT700

Motor connecter

CD changer unit

CD mechanism holder assembly

Pickup unit connector

2.

Remove the screw E attaching the shaft on the right side of the CD mechanism holder assembly. Pull outward the stopper fixing the shaft on the left side and remove the CD mechanism holder assembly from behind in the direction of the arrow y.

3.

Turn the CD mechanism holder assembly half around the lift up slide shaft h of the CD mechanism holder assembly until the turn table is reversed, and pull out the CD mechanism holder assembly.

Lift up slide shaft

Fig.11

E

Stopper

CD mechanism holder assembly

Fig.12

Lift up slide shaft n

CD mechanism holder assembly

Fig.14

y

CD mechanism holder assembly

Fig.13

1-11

MX-GT700

Removing the belt, the CD servo board and the switch board (See Fig.9 and 10)

Prior to performing the following procedure, remove the CD tray.

1.

Detach the belt from the pulley on the upper side of the CD changer unit (Do not stain the belt with grease).

2.

Disconnect the card wire from the pickup unit connector on the under side of the CD changer unit.

Attention : Solder is put up before the card wire is removed from the pick-up unit connector on the CD mechanism assembly. (When the card wire is removed without putting up solder, the CD pick-up unit assembly might destroy.)

3.

Disconnect the motor wire harness from connector on the CD servo board.

4.

Remove the screw C attaching the switch board and release the two tabs e attaching the switch board outward and detach the switch board.

5.

Remove the two screws D attaching the CD servo board and . First release the two tabs f and two tabs g attaching the CD servo board motor to raise the CD servo board slightly, then release the CD servo board.

Tabs e

C

Switch board

CW3

CD changer unit

Fig.9

CD servo board

D

Tabs g

Soldered parts

CD mechanism board

motor connecter

Pickup unit connector

Belt

Motor

Tabs f

If the tabs f and g are hard to release, it is recommendable to unsolder the two soldered parts on the motor terminal of the CD servo board.

Soldering

Card wire

Picup unit connector

Fig.10

1-12

Removing the CD mechanism holder assembly (mechanism included)

(See Fig.11 to 14)

1.

Disconnect the harness from connector on the CD mechanism board in the CD mechanism assembly on the under side of the CD changer unit. Disconnect the card wire from the pickup unit connector.

Attention : Solder is put up before the card wire is removed from the pick-up unit connector on the CD mechanism assembly. (Refer to Fig.10) (When the card wire is removed without putting up solder, the CD pick-up unit assembly might destroy.)

MX-GT700

Motor connecter

CD changer unit

CD mechanism holder assembly

Pickup unit connector

2.

Remove the screw E attaching the shaft on the right side of the CD mechanism holder assembly. Pull outward the stopper fixing the shaft on the left side and remove the CD mechanism holder assembly from behind in the direction of the arrow y.

3.

Turn the CD mechanism holder assembly half around the lift up slide shaft h of the CD mechanism holder assembly until the turn table is reversed, and pull out the CD mechanism holder assembly.

Lift up slide shaft

Fig.11

E

Stopper

CD mechanism holder assembly

Fig.12

Lift up slide shaft n

CD mechanism holder assembly

Fig.14

y

CD mechanism holder assembly

Fig.13

1-13

MX-GT700

•

Removing the CD mechanism holder from the CD chager unit. (Refer to "Removing the CD mechanism holder assembly" )

Removing the pickup unit (

1. Removing the cut washer on the feed gear sleeve and pull out the feed gear.

2. Remove the two screws A fixing the pickup shaft.

3. Removing the pickup unit.

Removing the motor board

1. Unsolder the motor terminal on the motor board.

2. Remove the moter board.

Removing the feed motor (

Remove the two motor fixing screws at B and removing the feed motor.

See Fig.1)

(See Fig.2)

See Fig.1)

A

Motor board

Shutter

Cut washer

B

Fig.1

Unsolder

Pickup unit

Feed Gear

Feed motor

Shaft

A

Removing the spindle motor

The spindle motor cannot be removed as a single unit. When removing the spindle motor, change the chasis and turntable together as aunit.

Spindle motor

Unsolder

Fig.2

1-14

MX-GT700

Removing the record/playback mechanism.

Removing the R/P head.

1. Remove the screw A on the right side of the R/P head.(Fig.1, Fig.2)

2. Remove the screw B on the left side of the R/P head.(Fig.1, Fig.2)

Remove the erase head.

Remove the screw C fixing the erase head.(Fig.1)

Removing the pinch roller.

1. Pull out the pinch roller by opening the pinch roller stopper outward to unlock .(Fig.3)

2. When reassembling the pinch roller, refer to fig. 4 to hook up the spring.

R/P Head

E. Head

Stoppsr

A

B

C

Fig.1

B

Pinch roller assembly

A

Spring

Pinch roller

Return spring

R/P Head

Fig.2

Pinch roller

stopper

Fig.3

Pinch roller

spring

Return spring

Fig.4

1-15

MX-GT700

Removing the motor.

1. Remove the two screws D fixing the motor. Be careful to grease's splash when the

drive belt comes off.(Fig.5, Fig.6)

2. Unsolder the motor terminal.(Fig.5)

Removing the mechanism board.

1.

coil terminal.(Fig.5)

2. Remove the two screws E fixing the board.(Fig.5)

Removing the flywheel.

capstan shaft, then remove the flywheel. When reassembling the flywheel, be sure to use new washers as they cannot be reused.(Fig.8, Fig.9)

Unsolder the four parts a on the solenoid

3. Unhook the three parts b from the board.(Fig.5)

4. Remove the mechanism board.(Fig.5)

Remove the cut-washers at c and d from the

Mecha.

a

Drive belt (Flat)

board

E

terminal

b

Motor

D

Fig.5

Fig.6

E

Drive belt

Motor

Drive belt

b

a

1-16

Sleeve

Flywheel

c

Washer

Sleeve

d

FR belt

Capstan

washer

Flywheel

Fig.7

FR belt

Fig.8Fig.9

Capstan

washer

Flywheel

< Speaker section >

It is exchange in a unit. Please do not decompose.

Removing the net assembly (See Fig. 1)

1.

Remove the four bosses attaching the net assembly and remove the net assembly.

MX-GT700

Net assembly

Boss

Fig.1

1-17

MX-GT700

Wiring connection

0

2

0

9

3809-001315

UCW7

2

0

AH39-20008Q

3809-001228

ACW5

ACW6

Amp. board

ACW2

ACW1

3809-001224

Power /CD switch board

UCW1

Front key switch board

0

9 0

AH39-00244A

AH39-00338A

UCW2

FL dispaly & system control board

Power transformer

RFS9

UCW3

RCW2

PCW1

UCW4

RFS2

UCW6

UCW5

AH39-20561P

3809-001121

CD mechanism

CW2

CW1

CW3

0

3809-001185

Color codes are shown below. 1 Brown 2 Red 3 Orange 4 Yellow 5 Green 6 Blue 7 Violet

0

9

8 Gray 9 White 0 Black

AAN1

0

2

0

2

AH38-12001A

CW102

CW103

9

CW105

CW107

CW101

CW104

CW3

9

CW106

CD servo board

0

3809-001034

2

0

9

AH39-00060A

AH39-00096D

1-18

3809-001184

3809-001222

Tuner board

0

JW1

0

9

2

9

0

9

0

FCW1

OCW

JCW1

JCW2

FCW3

Main board

FCW2

HCW3

WA999

FCW3

9

0

2

RCW6

0

9

RW2

9

0

9

0

9

RW1

2

0

2

9

0

HCW2

AH39-00247A

9

Headphone J.board

AH39-00022A

9

0 9

0

2

0

88

9

2

0

AH39-20002D

8

2

8

2

Adjustment method

1. Tuner

MX-GT700

ITEAM

Received FREQ. Adjustment

point

Output

* Adjustment Location of Tuner PCB

AM(MW) OSC Adjustment

530~1710 KHz

MO

1~7.0 0.5V

MAIN PCB

AM(MW) RF Adjustment

600 KHz

MA

Maximum Output(Fig.1)

VT

GND

Fig.1 OSC Voltage

TESTER

1-19

MX-GT700

FM THD Adjustment

SSG FREQ.

98 MHz

Adjustment point

FM DETECTOR COIL

(FM DET) Output

60 dB

Minumum Distortion (0.4% below) (Fig.2)

FM Search Level Adjustment

SSG FREQ. Adjustment

point

(SVR1)

BEACON SENSITIVITY SEMI-VR(20K )

98 MHz

Output GND

FM S.S.G

FM Antenna Terminal

Speaker Terminal

SET

output

Distortion Meter

Fig.2 IF CENTER and THD Adjustment

28 dB

FM Antenna

Input

Oscilloscope

Input

SET

Output

28 dB(

2dB)

Adjust SVR1 so that "TUNED" of FL T is lighted (Fig.3)

*Adjust FM S.S.G level to 28dB

AM(MW) I.F Adjustment

SSG FREQ. Frequency

450 kHz 520 kHz

Adjustment point

AM IF

Maximum output (Fig.4)

FM S.S.G

GND

FM IN

Fig.3 FM Auto Search Level Adjustment

60cm

OUTPUT

AM SSG 450KHZ

AM ANT IN

20 k

AM IF

Speaker Terminal

1-20

INPUT

VTVM Oscilloscope

OUTPUT

Fig.4 AM I.F Adjustment

2. Cassette Deck

To adjust tape speed

Notes

1) Measuring tape: i) VT-712/MTT-111(or equivalent)

(Tapes recorded with 3kHz)

ii) AC-225/MTT-5512(or equivalent)

2) Connect the cassette deck to the frequency counter as in fig.1.

Cassette Deck

SPK OUT

MX-GT700

Frequency Counter

output

Fig.1

Pre-Setup Condition

NOR

1 3KHz

SPEED Control

OUT (connected to the frequencycounter)

1) Deck 1:VT-712

2) Press PLAY SW button

To Adjust

Turn VSR1 to left and right (FRONT PCB)

3) Deck 2:Same as above

To adjust plabyback level/REC

Notes

1) Before the actual adjustment, clean the play/recording head.

2) Measuring tape : i) VT-703/MTT-114N(or equivalent 10kHz AZIMUTH control)

ii) AC-225/MTT-5512(or equivalent)

3) The cassette deck is connections as shown in fig.2.

Cassette Deck

SPK OUT

(GND)

Fig.2

VTVM

In Out

RemarkStandardPre-SetupItemStep

1%

range

Oscilloscope

1. Adjust Deck 1 Play Level

Pre-Setup Condition

AZIMUTH1 SPK OUT

(VTVM is connected to the scope)

After putting VT-703 into Deck 1

- Press FWD PLAY button.

To Adjust

Turn the control screw to as shownin Fig.3.

Max output and same phase (both channels)

RemarkStandardPre-SetupItemStep

After adjustment secure it with REGION LOCK.

1-21

MX-GT700

2. Adjust Deck 2 Play Level/REC BIAS

2

AZIMUTH1

Recording Bias Voltage

Pre-Setup Condition

SPK OUT (VTVM is connected to the scope)

Fig.4

Recording /Play head

After putting VT-703 into Deck 2

1)Press FWD PLAY button.

After putting AC-225 into Deck 2

1)Press REC PLAY button.

2)MAIN PCB JCW3, connectted to VTVM

To Adjust

Turn the control screw to as shown in Fig.3.

Turn JSR2L, JSR2R to the right and left

Max output and same phase (both channels)

7mV( 0.5mV)

RemarkStandardPre-SetupItemStep

After adjustment secure it with REGION LOCK.

AZIMUTH control screw

Audio OSC.

Fig.3

AUX IN

SET (MAIN PCB)

LINE OUT

IN

TP

JCW3

Fig.4

VTVM

IN OUT

Oscilloscope

1-22