JVC MXK-7 Service manual

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MX-K7

RM-SMXK3A REMOTE CONTROL

1 2 3

4 5 6

7 8 9

10 +10

CD1CD2CD3CD

PROGRAM

REPEAT TAPE A/B

/RANDOM

111

SOUND MODE

ACTIVE

BASS EX.

Contents

VOLUME

FM MODE

COMPU PLAY

CONTROL

3-CD

STANDBY/ON

CANCEL SET

/ DEMO

U A

REPEAT PROGRAM RANDOM

VOL

COMPU PLAY CONTROL

MAXMIN

EJECT

PLAY

FULL - LOGIC CONTROL CD SYNCHRO RECORDING

MX-K7

VCD NUMBERRETURNPBC

P A T

REC START

/STOP REC START DUBBING

PLAY & EXCHANGE

TUNNIG

CLOCK /TIMER

STANDBY/ON

SLEEP

AUX

FM /AM

TAPE

FADE

MUTING

COMPACT COMPONENT SYSTEM

STANDBY

PHONES

MIC MIC

ACTIVE BASS EXTENSION

CD-R/RW PLAYBACK

1 BIT

DUAL D/A CONVERTER

ACTIVE

BASS EX.

PRESET

SOUND

MODE

DISC SKIP

CD CONTROL

TAPE

A/B

EJECT

REC/PLAY

CA-M XK7SP-MXK7 SP-MXK7SP-DSK7 SP-DSK7

Recordable

ReWritable

Area Suffix

J U.S.A.

Safety precautions Important for laser products Preventing static electricity Disassembly method Adjustment method

1-2 1-3 1-4 1-5 1-18

Flow of functional

operation until TOC read Maintenance of laser pickup Replacement of laser pickup Description of major ICs

1-20 1-21 1-21 1-22

No.20958

May. 2001

MX-K7

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 metal part and a known good earth ground. Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to eachexposed 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 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.

In regard with component parts appearing on the silk-screen printed 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. When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer. (Except the J and C version)

1-2

Important for laser products

MX-K7

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 laserradiation and is equipped with safety switches whichprevent emission of radiation when the drawer is open and the safety interlocks have failed or are de feated. It is dangerous to defeat the safety switches.

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.

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.

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-K7

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 CD changer unit (optical pickup)

1. Do not subject the CD changer 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 CD changer 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

CD changer

unit

CD changer mechanism

assembly

Attention when traverse unit is decomposed

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

1. Remove the CD changer unit.

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

3. Solder is put up before the card wire is removed from connector CN601 on the main board as shown in Fig.1 and Fig. 2. (When the wire is removed without putting up solder, the CD pick-up assembly might destroy.)

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

1-4

Flexible cable

Fig.1

Soldering

Fig.2

MX-K7

Disassembly method

Commence disassembly of this set by removing the main units and then proceed to the components and assemblies inside the units.

Replacement of the fuses and the power IC

Top cover CD changer unit Front panel assembly Chassis unit

CD changer unit

Removing the main PCB Removing the CD changer mechanism assembly Removing the CD pickup Replacing the loading motor and belt of the CD changer tray Replacing the CD tray rotor belt of CD changer, and removing the motor

Front panel assembly

Removing the cassette deck mechanism Removing the earphone jack PCB Removing the control/FL PCB Removing the switch PCB and ACTIVE BASS EX. switch PCB Removing the cassette deck main motor, and replacing the main belts Removing the leaf switches of the cassette deck mechanism Removing the cassette deck heads

Chassis unit

Removing the 3-pin regulator Removing the power amp and supply PCB and the Power Trans PCB

1-5

MX-K7

Replacement of the fuses and the power IC

Replacing the fuses (See Fig.1)

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

Replace the fuses inside.

[Caution] Be sure to use fuses with the specified

ratings.

Replacing the power IC

(See Fig.2 and 3)

Prior to performing the following procedure, remove the top cover. Also remove the rear panel and power amp and supply PCB. (See Fig.33 to 37)

Remove the two screws "A" that retain the power IC.

Remove the solder fixing the power IC.

Fuse (F952)

1.6A 250V

Chassis

Fuse (F951)

3.15A 125V

Power trans PCB

Fig.1

Heat sink

Power amp and supply PCB

Fig.2

Power amp and supply PCB

Heat sink

Power IC soldering part

1-6

Fig.3

Removing the top cover

(See Fig.4 and 5)

Remove the six screws "B" that retain the top cover from the rear of the body.

Remove the four screws "C" that retain the top cover from the two sides of the body.

Remove the top cover from the body by lifting it toward the rear.

Top cover

MX-K7

Fig.4

Front panel assembly

Fig.5

1-7

MX-K7

Removing the CD changer unit

(See Fig.6 to 9)

Prior to performing the following procedures,

remove the top cover.

[Caution] Although the CD mechanism unit can be

removed without removing the CD tray panel, it is still recommended to remove it in order to prevent damage.

From the front panel side of this set, push in the sections marked with arrows and pull out the CD tray toward the front.

Remove the CD tray panel by pushing both of its extremities upward in the direction of the arrows.

Push the CD tray deep into the set.

Disconnect the cassette head wires from the connectors CN307 and CN308 on the main PCB, which is located below the CD changer unit.

Disconnect the card wires from the connectors CN301, CN302 and CN305 on the main PCB.

Disconnect the parallel wires from the connectors CN902A, CN902B and CN902C on the power amp and supply PCB.

From the rear of the set, remove the two screws "D" retaining the CD changer unit, then remove the three screws "E" and the screw "F" retaining the ANTENNA terminal and the AUX IN terminal.

Push down and disengage the two claws "a" holding the CD changer unit at the bottom of its front panel and then remove the CD changer unit (Fig. 9).

CD tray panel

Fig.6

1-8

AUX IN terminal

CD tray panel

Fig.7

ANTENNA

terminal

CD changer unit

Fig.8

Claw a

Fig.9

Removing the front panel assembly

(See Fig.10 and 11)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit.

Disconnect the parallel wire and card wire from the connectors CN101 and CN901 on the power amp and supply PCB.

Remove the two screws "G" retaining the front panel assembly onto the bottom of the body.

Remove the screw "H" retaining the cassette deck mechanism and then remove the GND lug "b" that comes from the power amp and supply PCB.

Remove the solder connecting the wire on the control/FL PCB.

Disengage the claws "c" on both sides at the bottom of the front panel assembly and then remove the assembly.

MX-K7

Claw c

GND lug b

Fig.10

Control/FL PCB

Power amp and supply PCB

Fig.11

1-9

MX-K7

Removing the main PCB

(See Fig.12 and 13)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit.

Disconnect the wires from CN602 and CN603 on the main PCB, which is located on the backside of the CD changer unit.

Disconnect the card wire from connector CN604 of the main PCB at the back of the CD changer unit.

The three screws "I" and the screw with the washer "J" that retain the main PCB should be removed.

Remove the main PCB by pulling it toward the side where the CN601 is located.

Using solder, short the CD pickup to connect to short round.

[Caution]

Disconnect the card wire from the connector CN601 on the main PCB and then remove the main PCB.

After re-connecting the wires, be sure to remove the shorting solder from the GND connection.

Main PCB

CN604

CN603CN602

Main PCB

Fig.12

CN601

1-10

Short round

Fig.13

Removing the CD changer mechanism

assembly (See Fig.14 to 16)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit.

Remove the spring "d" from the front surface of the CD changer mechanism unit.

Turn the CD changer mechanism unit upside down, and remove the spring "e" connecting the unit to the CD changer mechanism assembly.

[Note] When re-assembling after the disassembly

work, apply bonding agent on the spring to prevent it from slipping off.

Remove the two screws "K" retaining the CD changer mechanism assembly.

MX-K7

[Note]

Spring d

[Caution] When replacing the CD changer

mechanism assembly, be sure not to mistake the positions of the red and blue dampers.

CD changer mechanism assembly

Fig.15

CD changer unit

Fig.14

Red Red

[Note]

Spring e

CD changer mechanism assembly

Fig.16

BlueBlue

1-11

MX-K7

Removing the CD pickup (See Fig.17)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit. Also remove the CD changer mechanism

1.2.Widen the section "f ". While keeping the section "f" wide open, push the section "g" in the direction of the arrow to remove the shaft, and then remove the CD pickup.

Replacing the loading motor and belt

of the CD changer tray (See Fig.18)

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

Pull out the CD changer tray.

Remove the belt from the pulley.

Remove the two screws "L" retaining the CD changer tray loading motor.

[Caution] When pushing in the CD changer tray, be

sure to lower the CD changer mechanism assembly by manually turning the UD cam gear in the direction of the arrow.

Replacing the CD tray rotor belt of the

CD changer, and removing the motor

(See Fig.19 and 20)

Pulley

Belt

Shaft

CD pickup

Fig.17

UD cam gear

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit.

Remove the two screws "M" retaining the stopper brackets on both sides of the CD changer unit.

Remove the stopper brackets from both sides of the CD changer unit.

Pull out the CD tray from the CD changer unit, all the way and then lift the tray upward to remove.

Turn the CD tray upside down and remove the tray rotor belt from the pulley.

Turn the CD tray upside down and disconnect the card wire from the connector CN605 on the CD tray rotor motor assembly.

Remove the two screws "N" retaining the CD tray rotor motor, and then remove the CD tray rotor motor.

CD changer tray

Fig.18

CD tray rotor belt

1-12

Stopper bracket

Fig.19 Fig.20

CN605

Pulley

MX-K7

Removing the cassette deck mechanism

(See Fig.21)

Prior to performing the following procedure, remove

the top cover. Also remove the CD changer unit. Also remove the front panel assembly.

1.Remove the five screws "O" retaining the cassette deck mechanism from the back of the front panel assembly.

Removing the earphone jack PCB

(See Fig.22)

Prior to performing the following procedure, remove

the top cover Also remove the CD changer unit. Also remove the front panel assembly.

Remove the screw with the washer, "P" that retains

1. the earphone jack PCB from the back of the front panel assembly.

Fig.21

Front panel assembly

Earphone jack PCB

Removing the control/FL PCB

(See Fig.23)

Prior to performing the following procedure, remove

the top cover. Also remove the CD changer unit.

1.Remove the three screws "Q" that retain the control/FL PCB from the back of the front panel assembly.

Fig.22

Fig.23

Front panel assembly

Control/FL PCB

1-13

MX-K7

Removing the switch PCB and ACTIVE

BASS EX. switch PCB (See Fig.23 to 26)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit. Also remove the front panel assembly.

Pull out the volume control knob from the front of the front panel assembly.

Remove the nut and washer retaining the volume knob shaft.

Remove the three screws "Q" retaining the control/FL PCB from the back of the front panel assembly.

Remove the control/FL PCB.

Remove the eleven screws "R" retaining the switch PCB.

Remove the two screws "S" retaining the ACTIVE BASS EX. switch PCB.

Front panel assembly

Volume knob

Fig.24

Front panel assembly

Nut

Volume shaft

Washer

Fig.25

ACTIVE BASS EX. switch PCB

1-14

Switch

PCB

Fig.26

Removing the cassette deck main

motor, and replacing the main belts

(See Fig.21, 27 and 28)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit. Also remove the front panel assembly.

Remove the five screws "O" retaining the cassette deck mechanism.

Remove the cassette deck mechanism.

Remove the two screws "T" retaining the main motor from the front side of the cassette deck.

[Caution]

From the backside of the cassette deck, remove the main motor and two main belts.

After attaching the main motor, check the orientation of the motor and the polarity of the wires.

Cassette deck mechanism (Front side)

Fig.27

Cassette deck mechanism (Back side)

MX-K7

Cassette deck main motor

[Caution]

The lengths of the cassette A (playback only) and cassette B (record/play) main belts are different. When attaching the main belts, use the longer belt for cassette A.

Removing the leaf switches of the

cassette deck mechanism

(See Fig.21 and 29)

Prior to performing the following procedures,

remove the top cover. Also remove the CD changer unit. Also remove the front panel assembly.

Remove the five screws "O" that retain the cassette deck mechanism.

Remove the cassette deck mechanism.

Turn the cassette deck mechanism upside down.

Remove the solder from around the leaf switches.

Pull out the leaf switches from the front side of the cassette deck mechanism.

Main belt (For B cassette)

Solder side of leaf switch

Cassette deck mechanism (Back side)

Main belt (For A cassette)

Fig.28

Fig.29

1-15

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JVC MXK-7 Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual