Jvc MX-GT90 Service Manual

MX-GT80/MX-GT90

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MX-GT80 / MX-GT90

	CD-R/RW PLAYBACK
	MX-GT80
SP-MXGT80	CA-MXGT80	SP-MXGT80

						Area Suffix
					J	U.S.A.
					C	Canada

CD-R/RW PLAYBACK

MX-GT90

Each different point

Model CD/DECK/RECEIVER

MX-GT80 CA-MXGT80

MX-GT90 CA-MXGT90

Contents

Safety precautions Important for laser products Preventing static electricity Importance administering

point on the safety Disassembly method Adjustment method

SP-MXGT90 CA-MXGT90 SP-MXGT90

	SPEAKER	OUTPUT POWER
		MAIN SPEAKER	SUB WOOFER
	SP-MXGT80	55W / ch	130W / ch
	SP-MXGT90	70W / ch	160W / ch

1-2	Flow of functional operation
1-3	until TOC read	1-32
1-4	Maintenance of laser pickup	1-33
	Replacement of laser pickup	1-33
1-5	Description of major ICs	1-34
1-6
1-28

COPYRIGHT 2001 VICTOR COMPANY OF JAPAN, LTD.

No.20912

Feb. 2001

MX-GT80/MX-GT90

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	circuitry	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

AC VOLTMETER

metal part and a known good earth ground.

(Having 1000

Measure the

AC

voltage across the resistor

with the

ohms/volts,

AC voltmeter.

or more sensitivity)

Move the

resistor

connection

to eachexposed metal

part,

particularly

any exposed metal part having a

0.15

F

AC TYPE

return

path

to the

chassis, and meausre the AC

Place this

voltage across the

resistor. Now, reverse the plug in

probe on

the AC outlet and repeat each measurement. voltage

each exposed

1500

10W

measured Any must

not exceed 0.75 V AC

(r.m.s.).

metal part.

This

corresponds

to 0.5 mA AC (r.m.s.).

Good earth ground

1.

has been designed and manufactured to meet international

safety

standards.

This equipment

2. It

is the

legal responsibility of the repairer to ensure that these

safety

standards

are maintained.

3. Repairs

must 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 voltage.

!

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.

1-2

MX-GT80/MXGT90

Important for laser products

1.CLASS 1 LASER PRODUCT

2.DANGER : Invisible laser radiation when open and inter lock failed or defeated. Avoid direct exposure to beam.

3.CAUTION : There are no serviceable parts inside the Laser Unit. Do not disassemble the Laser Unit. Replace the complete Laser Unit if it malfunctions.

4.CAUTION : The compact disc player uses invisible laser radiation and is equipped with safety switches which prevent emission of radiation when the drawer is open and the safety interlocks have failed or are defeated. It is dangerous to defeat the safety switches.

5.CAUTION : If safety switches malfunction, the laser is able

to function.

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

! CAUTION Please use enough caution not to see the beam directly or touch it

in case of an adjustment or operation check.

VARNING : Osynlig laserstrålning är denna del är öppnad och spårren är urkopplad. Betrakta ej strålen.

VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle.Älä katso säteeseen.

ADVARSEL : Usynlig laserstråling ved åbning , når sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling.

ADVARSEL : Usynlig laserstråling ved åpning,når sikkerhetsbryteren er avslott. unngå utsettelse for stråling.

REPRODUCTION AND POSITION OF LABELS

WARNING LABEL

DANGER : Invisibie laser radiation when open and interlock or defeated.

AVOID DIRECT EXPOSURE TO

BEAM (e)

VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle.Älä

katso säteeseen. (d)

VARNING : Osynlig laserstrålning är denna del är öppnad och spårren är urkopplad. Betrakta ej strålen. (s)

ADVARSEL :Usynlig laserstråling ved åbning , når sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling. (f)

1-3

MX-GT80/MX-GT90

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 traverse unit is decomposed

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

CD changer mechanism assembly

1.Remove the disk stopper and T. bracket on the CD changer mechanism assembly.

2.Disconnect the harness from connector on the CD motor board.

3.CD traverse unit is put up as shown in Fig.1.

4.Solder is put up before the card wire is removed from connector CN601 on the CD servo control board as shown in Fig. 2.

(When the wire is removed without putting up solder, the CD pick-up assembly might destroy.)

5.Please remove solder after connecting the card wire with CN601 when you install picking up in the substrate.

CD traverse unit

Flexible cable

Fig.1

Soldering

Fig.2

1-4

MX-GT80/MXGT90

Importance administering point on the safety

F102

F101

F001

Caution: For continued protection against risk of fire, replace only with same type 5A/125V for F001, 6A/125V for F101 and F102. This symbol specifies type of fast operating fuse.

Precaution: Pour eviter risques de feux, remplacez le fusible de surete de F001 comme le meme type que 5A/125V, et 6A/125V pour F101 et F102.

^

Ce sont des fusibles suretes qui functionnes rapide.

1-5

MX-GT80/MX-GT90
Disassembly method	A

<Main body>

Removing the metal cover

(See Fig.1 to 3)

1. Remove the six screws A on the back of the body.

Metal cover

2.Remove the two screws B on both sides of the body.

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

	A				A
CAUTION: Do not break the front panel tab fitted to			Fig.1
the metal cover.
			Metal cover

B

Fig.2

Metal cover

B

Fig.3

1-6

Removing the CD changer mechanism assembly (See Fig.4 and 5)

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

1.Disconnect the card wire from connector CN661 on the Main board.

2.Remove the two screws C on the upper side of the body and the two screws D on the back of the rear panel.

3.Remove the plastic rivet attaching the main board.

4.Pull both the rear panel and the front panel assembly to the outside, then remove the CD changer mechanism assembly by lifting the rear part of the assembly.

CAUTION: To prevent damage to the CD fitting, be sure to pull both the rear panel and the front panel assembly enough to remove the CD changer mechanism assembly.

MX-GT80/MXGT90

Front panel assembly

C C

CD changer

Main board mechanism assembly CN661

Rear panel

Fig.4

CD changer mechanism assembly

Rear panel

Main board CN661

D

Plastic rivet

Front panel assembly

Fig.5

Removing the front panel assembly

(See Fig.6 to 10)

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

1.Disconnect the card wires from connector CN870, CN871 and CN315 on the main board respectively.

2.Remove the tie band and disconnect the wire from connector CN703 on the amplifier board.

3.Disconnect the wire from connector CN220 on the transformer board.

Amplifier board	Wire clamp	Main board
		CN870
CN703
		CN871
		CN315

Front panel assembly

	Transformer board
Fig.6	CN220

Front panel assembly

Main board

Fig.7

1-7

MX-GT80/MX-GT90

4. Remove the four screws E on the bottom of the	Front panel assembly	E
body.

5.Release the two joints a on the lower right and left sides of the body using a screwdriver, and remove the front panel assembly toward the front.

(Bottom)

Fig.8

Front panel assembly

Joint a

Fig.9

Joint a	Front panel assembly

Fig.10

1-8

Removing the tuner board

(See Fig.11 and 12)

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

1.Disconnect the card wire from connector CN1 on the antenna board on the right side of the body.

2.Remove the plastic rivet fixing the antenna board.

3.Remove the two screws F on the back of the body.

Removing the rear cover / rear panel (See Fig.12 to 15)

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

1.Remove the screw G attaching the rear cover on the back of the body.

2.Push each tab of the four joints b in the direction of the arrow and release.

3.Remove the eleven screws F attaching the rear panel.

4.Release the joints c on each lower side of the rear panel using a screwdriver and remove the rear panel backward.

Note : Remove the tuner board in case of necessity. (Refer to Fig.21)

MX-GT80/MXGT90

	Plastic rivet
CN1	Tuner board

Rear panel

Fig.11

G Rear panel

F

Joint b

Joint b

Rear cover

Fig.12

Rear panel

F

F

F								F

Fig.13

Joint c	Rear panel	Rear panel	Joint c
	Fig.15	Fig.14

1-9

MX-GT80/MX-GT90

Removing the main board

(See Fig.16 and 17)

Prior to performing the following procedure, remove the metal cover, the CD changer mechanism assembly, the rear panel and the tuner board.

1.Disconnect the card wires from connector CN870, CN871 and CN315 on the main board.

2.Disconnect the flat wires from connector CN704 and CN706 on the amplifier board.

3.Remove the screw H attaching the main board on the right side of the body.

4.Disconnect connector CN211 and CN212 on the main board from the regulator board.

Main board
CN870	Front panel assembly
CN871

CN315

Amplifier board

CN704

CN706

Fig.16

Front panel assembly

Plastic rivet

Main board

	Regulator board			CN211
		H
				CN212

Fig.17

Removing the speaker board

(See Fig.18)

Speaker board

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

REFERENCE: It is not necessary to remove the main board.

1.Disconnect connector CN217 on the speaker board from the regulator board.

Regulator board

CN217

Fig.18

1-10

Removing the amplifier board / voltage board / heat sink (See Fig.19 and 20)

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

1.Disconnect the wires from connector CN703, CN704 and CN706 on the amplifier board respectively.

2.Remove the two tie band attaching the wire to the amplifier board and the voltage board.

3.Disconnect connector CN215 on the amplifier board and CN216 on the voltage board from the regulator board (The heat sink and heat sink bracket will be detached at once).

4.Pull out the upper and lower heat sink brackets from the heat sink respectively.

5.Remove the four screws I attaching the amplifier board to the heat sink.

6.Remove the two screws J, the board bracket and the voltage board.

MX-GT80/MXGT90

Amplifier board Tie band

CN703

CN704

Tie band

Voltage board

CN703

Regulator board

CN216 CN215

Fig.19

Amplifier board

Heat sink bracket

Heat sink

I

Voltage board

I

J

Heat sink bracket

Fig.20

1-11

MX-GT80/MX-GT90

Removing the power transformer assembly (See Fig.21 and 22)

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

1.Disconnect the wires from connector CN220 and CN250 on the transformer board.

2.Disconnect the wire from connector CN204 on the regulator board.

3.Remove the four screws k attaching the transformer assembly.

Removing the regulator board

(See Fig.23)

Prior to performing the following procedure, remove metal cover, CD changer mechanism assembly, rear panel, tuner board, main board, amplifier board, voltage board and speaker board.

1.Disconnect the wire from connector CN204 on the regulator board.

2.Remove the two screws L attaching the regulator board.

Removing the power cord (See Fig.21)

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

1.Disconnect the wire from connector CN250 on the transformer board.

2.Remove the tie band from the voltage board.

3.Move the power cord stopper upward and pull out it from the base chassis.

Transformer board

CN250

Tie band

CN220

Voltage board

Power cord

Base chassis

Power cord stopper

Power transformer assembly

	Fig.21
Transformer board
Regulator board	CN220
CN204	K

Power transformer assembly

K

Tie band

CN250

Power cord stopper

Fig.22

CN204

Power transformer assembly

L

L

Regulator board

Fig.23

1-12

<Front panel assembly>

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

Removing the cassette mechanism assembly (See Fig.24)

1.Disconnect the card wire from connector CN306 on the head amplifier & mechanism control board.

2.Remove the four screws M and three screws M' attaching the cassette mechanism assembly.

MX-GT80/MXGT90

Head amplifier
& Mechanism control board	M
CN306

M										M
M'										M'
Cassette mechanism						M'
assembly					Fig.24

N

Removing the display system control board (See Fig.25 to 27)

1. Remove the five screws N attaching the stay bracket.

N

2.Disconnect the card wires from connector CN316 and CN880 on the display system control board.

3.Remove the seven screws O attaching the display system control board.

4.If necessary, disconnect the wire from connector CN911 on the front side of the display system control board and unsolder FW915.

If necessary, remove the CD play board. (Fig. 28)

Removing the CD play board

(See Fig.27 and 28)

1.Remove the three screws P attaching the CD eject board.

2.If necessary, unsolder FW915 on the CD eject board.

Display system control board

Fig.25

O CN316

O

FW915 (Soldering)

O

Stay bracket

O

O

				P		CN880	Display system control board
	CD playt board					Fig.26
	FW915
	(Soldering)						CD play board
						CN911
	P						FW915
							FW915

Display system control board

Fig.28

Fig.27

1-13

MX-GT80/MX-GT90

Removing the preset / tuning switch board (See Fig.29 and 30)

Preset / tuning switch board

Prior to performing the following procedure, remove

the display system control board.

Q

1.Pull out the preset knob on the front panel.

2.Remove the five screws Q attaching the preset / tuning switch board.

3.If necessary, unsolder FW901 on the preset / tuning switch board.

Q

Fig.29

Removing the operation switch board (See Fig.30 and 31)

Prior to performing the following procedure, remove the display system control board and the preset / tuning switch board.

1.Pull out the volume knob on the front panel and remove the nut. Pull out the surround mode knob and the surround woofer level knob toward the front.

2.Remove the twelve screws R attaching the operation switch board.

3.Remove the screw R' attaching the earth terminal extending from the switch board.

4.Release each tab of the seven joints g retaining the operation switch board.

Preset knob	Surround mode knob

Surround woofer level knob

Nut

Volume knob

Fig.30

R

Joints g

		R
	Joint g	Operation
		switch board

R

Joint g

R

Joint g

Joints g R	R	R	R'

Fig.31

1-14

MX-GT80/MXGT90

Speaker section 1 (SP-MXGT80)

Removing the front panel (See Fig.1)

1.	Remove the four screws A attaching the front panel	A	A
	on the front of the body.
2.	Pull out the front panel toward the front.

Front panel

Removing the speaker (tweeter)

(See Fig.2)

Prior to performing the following procedures, remove the front panel.

1.Remove the two screws B attaching the speaker (tweeter) on the front of the body.

2.Disconnect the wire from two speaker terminals of the speaker (tweeter).

A A

Fig.1

B

Speaker (squawker)

Removing the speaker (squawker)

(See Fig.3)

Prior to performing the following procedures, remove

the front panel.

Speaker (tweeter)

1.Remove the four screws C attaching the speaker (squawker) on the front of the body.

Fig.2

2. Disconnect the wire from the two speaker terminals of the speaker (squawker).

Speaker (squawker)

C

C

Fig.3

1-15