JVC MXG-750-V, MXG-850-V, MXG-950-V, MXG-880-V Service manual

MX-G950V/MX-G880V

MX-G850V/MX-G750V

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MX-G950V/MX-G880V MX-G850V/MX-G750V

CA-MXG950V

COMPACT

DIGITAL VIDEO

COMPACT

DIGITAL AUDIO

MX-G950V/MX-G850V

U-----------------Other Areas UN----------------------- Asean UX---------------Saudi Arabia

Contents

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

CA-MXG850V CA-MXG880V

MX-G880V

Area Suffix

UN----------------------- Asean

1-2 1-3 1-4 1-5 1-28

Flow of functional operation until TOC read (CD) Maintenance of laser pickup Replacement of laser pickup Description of major ICs

Area Suffix

CA-MXG750V

MX-G750V

Area Suffix

UN----------------------- Asean US ----------------- Singapore UX---------------Saudi Arabia

1-33 1-34 1-34 1-35~56

No.21099

Jul. 2002

1-1

MX-G950V/MX-G880V MX-G850V/MX-G750V

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 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 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.

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

1-2

MX-G950V/MX-G880V MX-G850V/MX-G750V

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.

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 changer mechanism

assembly

CD traverse

unit

Flexible cable

Fig.1

Soldering

Fig.2

1-3

MX-G950V/MX-G880V MX-G850V/MX-G750V

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.

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

CLASS 1 LASER PRODUCT

1-4

MX-G950V/MX-G880V MX-G850V/MX-G750V

Disassembly method

Removing the metal cover

(See Fig.1 ~ 3)

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

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

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

CAUTION:

Do not break the front panel tab fitted to the metal cover.

Metal cover

(CA-MXG850VU, CA-MXG950VUX)

Fig.1

Metal cover

Fig.2

Fig.1

(CA-MXG750VUS)

Metal cover

Fig.3

1-5

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the CD changer mechanism assembly (See Fig.4, 6)

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

Disconnect the wire from connector CN705 on the amplifier board.

Remove the plastic rivet attaching the main board to the front assembly on the right side of the body.

Disconnect the card wire from connector CN661 on the main board.

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

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.

CD changer mechanism assembly

Rear panel

Amplifier board

CN705

Fig.4

Front panel assembly

Main board

CN661

Front panel assembly

CD changer mechanism assembly

REFERENCE:

At this point, one card wire on the underside of the CD mechanism assembly is still connected.

Disconnect the card wire from connector CN504 on the inner side of the main board on the right side of the body. Remove the CD mechanism 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.

CN504

Fig.5

CD changer mechanism assembly

Plastic rivet

Main board

CN661

CN504

Front panel assembly

Fig.6

(CA-MXG850VU, CA-MXG950VUX)

CD changer mechanism assembly

Rear panel

1-6

Plastic rivet

Main board

CN661

CN504

Front panel assembly

Fig.6

(CA-MXG750VUS)

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the fan (See Fig.7)

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

Turn over the CD changer mechanism assembly and remove the two screws E attaching the fan.

Removing the front panel assembly

(See Fig.8 ~ 11)

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

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

Amplifier board

CN703

Fan

CD changer mechanism assembly

Fig.7

Band

Main board

CN870

CN871

CN315

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

Disconnect the wire from connector CN220 on the transformer board.

Remove the two screws F on the bottom of the body.

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.

Transformer board

CN220

Fig.8

(Bottom)

Fig.9

Front panel assembly

Fig.10

Joint a

Front panel assembly

Fig.11

1-7

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the tuner board

(See Fig.12)

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

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

Remove the plastic rivet fixing the tuner board.

Remove the two screws G on the back of the body.

Removing the rear cover / rear panel

(See Fig.13 ~ 16)

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

Remove the screw H attaching the rear cover on the back of the body.

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

Remove the sixteen screws G attaching the rear panel.

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

Plastic rivet

Joint b

Rear cover

(CA-MXG850VU, CA-MXG950VUX)

CN1

Tuner board

Fig.12

Fig.13

Rear panel

Joint b

Rear panel

Fig.14

(CA-MXG850VU, CA-MXG950VUX)

Rear panel

Fig.15

Joint c

G G

Joint b

Rear cover

Joint b

Fig.13

(CA-MXG750VUS)

Rear panel

Fig.14

(CA-MXG750VUS)

1-8

MX-G950V/MX-G880V MX-G850V/MX-G750V

Joint c

Rear panel

Fig.16

(CA-MXG850VU, CA-MXG950VUX)

Removing the main board

(See Fig.17 ~ 19)

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

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

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

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

Disconnect the wire from connector CN710 on the speaker board.

CN315

Amplifier board

CN704 CN706

Main board

Joint c

Fig.16

(CA-MXG750VUS)

Main board

CN870

CN871

Fig.17

Rear panel

Front panel assembly

Amplifier board CN704, CN706

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

Front panel assembly

Main board

Regulator board

CN212

CN211

Fig.19

Speaker board

CN710

Fig.18

(CA-MXG850VU, CA-MXG950VUX)

Amplifier board

CN704, CN706

Main board

Speaker board

CN710

Fig.18

(CA-MXG750VUS)

1-9

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the speaker board

(See Fig.20)

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

REFERENCE:

Disconnect the wire from connector CN710 on the speaker board.

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

It is not necessary to remove the main board.

Speaker board

CN701

Regulator board

CN217

Fig.20

(CA-MXG850VU, CA-MXG950VUX)

Speaker board

CN710

Removing the power board (See Fig.21)

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

Remove a band on the power board.

Disconnect the wire from connector CN218, CN219 and CN250 on the power board.

Disconnect connector CN213 on the power board from the regulator board.

Regulator board

Power board

CN219

CN250

CN213

Fig.20

CN217

(CA-MXG750VUS)

CN218

Band

Fig.21

1-10

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the amplifier board / voltage board / heat sink (See Fig.22, 23)

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

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

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

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

Remove the four screws J attaching the amplifier board to the heat sink.

Remove the two screws K, the board bracket and the voltage board.

REFERENCE:

It is not necessary to remove the power board.

Voltage board

Regulator board

Heat sink

Voltage board

Amplifier board

CN704 CN706

Band

CN216

Fig.22

Band

CN703

CN215

Amplifier board

CA-MXG850VU, CA-MXG950VUX)

Heat sink

Voltage board

Board bracket

Fig.23

Amplifier board

Board bracket

Fig.23

(CA-MXG750VUS)

1-11

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the power transformer assembly (See Fig.24, 25)

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

Disconnect the wires from connector CN218 and CN219 on the power board.

Disconnect the wire from connector CN204 on the regulator board.

Disconnect the wire from connector CN220 on the transformer board.

Remove a band on the voltage board.

Release the wire from the stopper on the regulator board.

Remove the four screws L attaching the transformer assembly.

Power board

CN219

CN218

Band

Transformer board

CN220

Power transformer assembly

Fig.24

Stopper

Regulator board

CN204

Removing the regulator board

(See Fig.26)

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

Disconnect the wire from connector CN204 on the regulator board.

Release the wire from the stopper on the regulator board.

Remove the two screws M attaching the reglator board.

Removing the power cord (See Fig.27)

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

Disconnect the wire from connector CN250 on the power board.

Power transformer assembly

Power board

CN250

Power cord stopper

Fig.25

Fig.26

Regulator board

CN204

Stopper

Regulator board

CN204

Remove the band from the power board.

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

1-12

Base chassis

Band

Fig.27

MX-G950V/MX-G880V MX-G850V/MX-G750V

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.28)

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

Remove the seven screws N attaching the cassette mechanism assembly.

Removing the display system control board (See Fig.29 ~ 31)

Remove the four screws O attaching the stay bracket.

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

Head amplifier & mechanismcontrol board CN306

Cassette mechanism assembly

Fig.28

Remove the seven screws P attaching the display system control board.

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

Removing the CD eject board

(See Fig.31, 32)

Remove the three screws Q attaching the CD eject board.

If necessary, unsolder FW915 on the CD eject board.

CD eject board

CN911

FW915

Display system control board

CN316

FW915

(Solding)

CN880

CD eject board

FW915

(Solding)

Stay bracket

Fig.29

CN911

Display system control board

Fig.30

Display system control board

Fig.31

Fig.32

1-13

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the preset / tuning switch board (See Fig.33, 34)

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

Pull out the preset knob on the front panel.

Remove the four screws R attaching the preset / tuning switch board.

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

Removing the operation switch board

(See Fig.34, 35)

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

Pull out the volume knob on the front panel and remove the nut. Pull out the sound mode knob, the mic level knob and the sub woofer level knob toward the front.

Preset / tuning switch board

FW901

(Solding)

Preset knob

Fig.33

Sound mode knob

Sub woofer level knob

Remove the twelve screws S attaching the operation switch board.

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

Joint g

Volume knob

Joint g

Mic level knob

Nut

Fig.33

Operation switch board

1-14

Joint g

Fig.35

Joint g

Disassembly method

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the front cover (See Fig.1,2)

CAUTION:

Remove the four screws A on the front of the body respectively.

Remove the front cover toward the front and disconnect the yellow and black wires from the two tweeter speaker terminals.

Do not break or damage the front panel and body that are glued at the joints a.

(See Fig.1)

Joint a

Joint a Joint a

Front cover

Joint a

Fig.1 (SP-MXG750V) (SP-MXG850V) (SP-MXG950V)

Tweeter speaker

Woofer speaker

(SP-MXG750V) (SP-MXG850V) (SP-MXG950V)

Fig.2

1-15

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the woofer speaker (See Fig.3)

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

Remove the four screws B on the front of the body.

Pull out the woofer speaker toward the front and disconnect the wire (yellow and black,red and black) from the two speaker terminals.

Removing the tweeter speaker

(See Fig.4)

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

Disconnect the red and black wires from the two tweeter speaker terminals.

Remove the two screws C attaching the tweeter speaker on the back of the front cover.

Woofer speaker

Fig.3 (SP-MXG750V) (SP-MXG850V) (SP-MXG950V)

Tweeter speaker

1-16

Front cover

Fig.4 (SP-MXG750V) (SP-MXG850V) (SP-MXG950V)

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the front cover (See Fig.5)

CAUTION:

Remove the four screws D on the front of the body respectively.

Remove the front cover toward the front.

Do not break or damage the front panel and body that are glued at the joints b.

(See Fig.5)

Joint b

Joint b Joint b

Front cover

Joint b

Removing the woofer speaker (See Fig.6)

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

Remove the four screws E on the front of the body.

Pull out the woofer speaker toward the front and disconnect the red and black wires from the two speaker terminals.

Fig.5 (SP-MXG850V) (SP-MXG950V)

Woofer speaker

Fig.6 (SP-MXG850V) (SP-MXG950V)

1-17

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the Rear cover (See Fig.7 ~ 9 )

Remove the four screws F on the back of the body.

Disconnect the wires from the two terminals on the rear speaker.

Remove the four screws G on the back of the front cover.

Rear cover

Fig.7(SP-MXG950V)

Rear cover

Front cover

Rear speaker

Fig.8(SP-MXG950V)

terminals

Rear speaker

Front cover

1-18

Rear speaker

Fig.9(SP-MXG950V)

terminals

Removing the CD Servo control board (See Fig.1)

1.Remove the metal cover.

2.Remove the CD changer mechanism assembly.

3.From bottom side the CD changer mechanism assembly, remove the four screws A retaining the CD servo control board.

4.Absorb the four soldered positions "a" of the right and left motors with a soldering absorber.

5.Pull out the earth wire on the CD changer mechanism assembly.

6.Disconnect the connector CN854 on the CD servo control board.

7.Disconnect the card wire CN601 and the connector CN801 on the CD servo control board.

MX-G950V/MX-G880V MX-G850V/MX-G750V

CN854

CN651

CD servo control board

CN652

CN801

CN601

CN151

Removing the CD tray assembly (See Fig.2~4)

Remove the front panel assembly.

1. Remove the CD changer mechanism assembly.

2. Remove the CD Servo control board.

3. Remove the screw B' retaining the lod stopper.

4. From the T.bracket section "b" and clamper base

5. section "c" , remove both of the edges fixing the rod(See Fig.2 and 3). Remove the screw B retaining the disc stopper

6. (See Fig.3). Remove the three screws C retaining the T.bracket

7. (See Fig.3). Remove the screw D retaining the clamper assembly

8. (See Fig.3). From the left side face of the chassis assembly, remove

9. the one screw E retaining both of the return spring and lock lever(See Fig. 4).

10.

By removing the pawl at the section "d" fixing the return spring, dismount the return spring(See Fig.4).

11.

Remove the three lock levers(See Fig.4).

T.Braket

Disc stopper

Earth

wire

Fig.1

Clamper base

Rod

T.Braket

Fig.2

Lod stopper (C/J version only)

Lock lever

Clamper ass'y

Fig.3

Fig.4

Return spring

1-19

MX-G950V/MX-G880V MX-G850V/MX-G750V

11.

Check whether the lifter unit stopper has been caught into the hole at the section "e" of CD tray assembly as shown in Fig.5. Make sure that the driver unit elevator is positioned as

12. shown in Fig.6 from to the second or fifth hole on the left side face of the CD changer mechanism assembly.

[Caution]

13.

14.

15.

Chassis assembly

In case the driver unit elevator is not at above position, set the elevator to the position as shown in Fig.7 by manually turning the pulley gear as shown in Fig.8.

Manually turn the motor pulley in the clockwise direction until the lifter unit stopper is lowered from the section "e" of CD tray assembly(See Fig.8). Pull out all of the three stages of CD tray assembly in the arrow direction "f" until these stages stop (See Fig.6). At the position where the CD tray assembly has stopped, pull out the CD tray assembly while pressing the two pawls "g and g' " on the back side of CD tray assembly(See Fig.9). In this case, it is easy to pull out the assembly when it is pulled out first from the stage CD tray assembly.

Stopper

CD tray assembly

Fig.5

Refer to Fig.7

Pulley gear

Pawl

Fig.6

CD tray assembly

Drive unit of elevator

Fig.7

CD tray assembly

1-20

Motor pulley

Fig.8

Pawl ,

Fig.9

Removing the CD loading mechanism assembly(See Fig.10)

1.2.While turning the cams R1 and R2 assembly in the arrow direction "h" ,align the shaft "i" of the CD loading mechanism assembly to the position shown in Fig.10. Remove the four screws F retaining the CD loading mechanism assembly.

Removing the CD traverse mechanism (See Fig.11 and 12 )

For dismounting only the CD traverse mechanism

1. without removing the CD loading mechanism assembly, align the shaft "j" of the CD loading mechanism assembly to the position shown Fig.11 while turning the cam R1 and R2 assembly in the arrow direction "k" . By raising the CD loading mechanism assembly in the

2. arrow direction "l", remove the assembly from the lifter unit

MX-G950V/MX-G880V MX-G850V/MX-G750V

Cams R1, R2 assembly

Arrow

Cam R1, R2 assembly

Fig.11

Arrow

CD loading mechanism assembly

Fig.10

CD traverse mechanism

Lifter unit

Fig.12

CD Pickup unit

Arrow

Removing the CD pick unit (See Fig.13 )

Move the cam gear in the arrow direction "m" . Then, the CD pickup unit will be moved in the arrow direction "n" . According to the above step, shift the CD pickup unit to

2. the center position. While pressing the stopper retaining the shaft in the

3. arrow direction "o" , pull out the shaft in the arrow direction "p". After dismounting the shaft from the CD pickup unit,

4. remove the CD pickup unit

Shaft

Stopper

Fig.13

Shaft

Stopper

CD loading mechanism

Shaft

Cam gear

1-21

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the try select switch board (See Fig.14)

1.2.Remove the two screws G retaining the tray select switch board. Disconnect the tray select switch board from connector CN804 on the CD servo control board.

Removing the cam unit (See Fig.15 ~17 )

Remove the CD loading mechanism assembly.

While turning the cam gear "q", align the Paul "r" position of the drive unit to the notch position(Fig.16) on the cam gear "q". Pull out the drive unit and cylinder gear(See Fig.17).

3. While turning the cam gear "q", align the Paul "s"

4. position of the select lever to the notch position(Fig.18) on the cam gear "q". Remove the four screws H retaining the cam unit(cam

5. gear "q" and cams R1/R2 assembly)(See Fig.18).

Chassis assembly

Drive unit

CN851

CN854

Fig.14

Cam gear

Tray select switch board

CN804

Drive unit

Cylinder gear

Cam gear

Fig.15

Cams R1, R2 assembly

Cam unit

1-22

Fig.16

Select lever

Fig.17

MX-G950V/MX-G880V

Fig.18

Fig.20

Fig.19

Fig.21

[Note]

When the chassis assembly is turned over under the conditions wherein the gear bracket and belt have been removed, then the pulley gear as well as the gear, etc. constituting the gear unit can possibly be separated to pieces. In such a case, assemble these parts by referring to the assembly and configuration diagram in Fig. 21.

Removing the actuator motor and belt (See Fig.18~21)

Remove the two screws I retaining the gear bracket (See Fig.18). While pressing the pawl "t" fixing the gear bracket in the arrow direction, remove the gear bracket (See Fig.18). From the notch "u section" on the chassis assembly fixing the edge of gear bracket, remove and take out the gear bracket(See Fig. 19). Remove the belts respectively from the right and left actuator motor pulleys and pulley gears(See Fig. 18). After turning over the chassis assembly, remove the actuator motor while spreading the four pawls "v" fixing the right and left actuator motors in the arrow direction(See Fig. 20).

Pulley gear

Belt

Motor pulley

Belt

Pulley gear

Motor pulley

Gear bracket

Pawl

Actuator motor

Chassis assembly

Gear bracket

Pulley gear

Gear B

Cylinder gear

Gross gear U

Gear C

Gross gear L

Select gear

Gear B

Gear C

Pulley gear

Assembly and Configuration Diagram

MX-G850V/MX-G750V

1-23

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the cams R1/R2 assembly and cam gear q(See Fig.22)

Remove the slit washer fixing the cams R1 and R2 assembly.

By removing the two pawls "w" fixing the cam R1, separate R2 from R1. Remove the slit washer fixing the cam gear "q".

3. Pull out the cam gear "q" from the C.G. base assembly.

Removing the C.G. base assembly (See Fig.22 and 23)

Remove the three screws J retaining the C.G. base assembly.

[Caution]

To reassemble the cylinder gear, etc.with the cam unit (cam gear and cans R1/R2 assembly), gear unit and drive unit, align the position of the pawl "x" on the drive unit to that of the notch on the cam gear "q". Then, make sure that the gear unit is engaged by turning the cam gear "q" (See Fig. 24).

Slit washer

Cam gear q

Slit washer

Cam R2

Pawl

Cam R1

Cam switch board

C.G. base assembly

Pawl

Notch

Pawl

Cylinder gear

Drive unit

Fig.22

Cam gear q

Cam R1, R2 assembly

Gear unit

Gear bracket

Fig.23

1-24

MX-G950V/MX-G880V MX-G850V/MX-G750V

< Cassette mechanism section >

Removing the playback,recording and eraser heads (See Fig.1~3)

1. While shifting the trigger arms seen on the right side of the head mount in the arrow direction,turn the flywheel R in counterclockwise direction until the head mount has gone out with a click (See Fig. 1).

2. When the flywheel R is rotated in counterclockwise direction, the playback / recording & eraser head will be turned in counterclockwise direction from the position in Fig.2 to that in Fig.3.

3. At this position, disconnect the flexible P.C.board (outgoing from the playback head) from the connector CN301 on the head amp. and mechanism control P.C. board.

4. Remove the flexible P.C.board from the chassis base.

5. Remove the spring "a" from behind the playback / recording head.

6. Loosen the reversing azimuth screw retaining the playback head.

7. Take out the playback head from the front of the head mount.

8. The recording and eraser heads should also be removed similarly according to Steps 1~7 above.

Flexible P.C.board

Cassette mechanism

Trigger armHead mount

Fig.1

Playback/Recording & eraser head

(Mechanism A side)

Flywheel R

Spring "a"

Trigger arm

Reassembling the playback, recording

and eraser heads (See Fig.3)

1. Reassemble the playback head from the front of the head mount to the position as shown in Fig.3.

2. Fix the reversing azimuth screw.

3. Set the spring a from behind the playback head.

4. Attach the flexible P.C.board to the chassis base as shown in Fig.3.

5. The recording and eraser heads should also be reassembled similarly according to Steps 1~4 above.

CN301

Head amplifier & mechanism control P.C. board

Fig.2

Playback head

Spring "a"

CN302

FPC holder

Fig.3

Flywheel R

(Mechanism A side)

Reversing azimuth screw

Head mount

Flexible P.C.board

Head amplifier & mechanism control P.C. board

(Mechanism B side)

1-25

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the head amp. and mechanism control board (See Fig. 4)

1.Remove the cassette mechanism assembly.

2.After turning over the cassette mechanism

assembly,remove the five screws "A" retaining the head amplifier & mechanism control board.

3.Disconnect the connectors CN303 on the board

and the connectors CN301 and on CN302 both the right and left side reel pulse boards.

4.When necessary, remove the 4pin parallel

wire soldered to the main motor

Removing the capstan motor assembly

(See Fig.5 to 7)

1.Remove the six screws "B" retaining capstan

motor assembly (See Fig. 5).

2.While raising the capstan motor, remove the

capstan belts A and B respectively from the motor pulley (See Fig. 6).

Caution 1: Be sure to handle the capstan belts so carefully that these belts will not be stained by grease and other foreign matter. Moreover, these belts should be hand while referring to the capstan belt hanging method.(See Fig.6 and 7)

Flexible board

Head amplifier & mechanism control board

CN303

CN302 CN301

Flexible board

Fig.4

Capstan motor assembly

1-26

Capstan belt A

Fig.5

Capstan motor

Capstan belt A

Capstan belt B

Motor pulley

Fig.7 Fig.6

BBBB

Capstan belt B

MX-G950V/MX-G880V MX-G850V/MX-G750V

Removing the capstan motor (See Fig. 8)

From the joint bracket, remove the two screws "C" retaining the capstan motor.

Removing the flywheel (See Fig. 9,10)

1.Remove the head amp. and mechanism control P.C.Board.

2.Remove the capstan motor assembly.

3.After turning over the cassette mechanism, remove the two slit washers "b" fixing the capstan shafts R and L, and pull out the flywheels R and L respectively from behind the cassette mechanism.

Capstan motor

Joint bracket

Fig.8

Flywheel R Flywheel L

Fig.10

Removing the reel pulse board and solenoid (See Fig. 11)

1.Remove the five pawls (c,d,e,f,g) retaining the reel pulse P.C.Board.

2.From the surface of the reel pulse P.C.Board parts, remove the two pawls "h" and "i" retaining the solenoid.

Solenoid

Slit washer "a"

Fig.9

Slit washer "b"

Reel pulse board

Solenoid

Fig.11

1-27

MX-G950V/MX-G880V MX-G850V/MX-G750V

Adjustment method

Measurement instruments required for adjustment

1. Low frequency oscillator, This oscillator should have a capacity to output 0dBs to 600ohm at an oscillation frequency of 50Hz-20kHz.

2. Attenuator impedance : 600ohm

3. Electronic voltmeter

4. Frequency counter

5. Wow flutter meter

6. Test tape VT712 : For Tape speed and wow flutter ( 3kHz) VT710 : Head azimuth VT724 : For Reference level (1kHz)

7. Blank tape TAPE : AC-225

8. Torque gauge : For play and back tension Forward ; TW2111A, Reverse ; TW2121A Fast Forward and Rewind ; TW2231A

9. Test disc : CTS-1000(12cm),GRG-1211(8cm)

10. Jitter meter

Radio input signal

AM modulation frequency : 400Hz Modulation factor : 30% FM modulation frequency : 400Hz Frequency displacement : 22.5kHz

Frequency Range

AM 531kHz~1710kHz FM 87.5MHz~108MHz

Standard measurement positions of volume and switch

Power : Standby (Light STANDBY Indicator) Sub woofer VOL. : Minimum Sound mode : OFF Main VOL. : 0 Minimum Traverse mecha set position : Disc 1 Mic MIX VOL : MAX ECHO : OFF

Measurement conditions

Power supply voltage

AC110V/127V/220V/230V 240V , adjustable

Measurement output terminal : Speaker out : TP101(Mesuring for TUNER/DECK/CD) : Dummy load 6ohm

Precautions for measurement

1. Apply 30pF and 33kohm to the IF sweeper output side and 0.082 F and 100kohm in series to the sweeper input side.

2. The IF sweeper output level should be made as low as possible within the adjustable range.

3. Since the IF sweeper is a fixed device, there is no need to adjust this sweeper.

4. Since a ceramic oscillator is used, there is no need to perform any MPX adjustment.

5. Since a fixed coil is used, there is no need to adjust the FM tracking.

6. The input and output earth systems are separated. In case of simultaneously measuring the voltage in both of the input and output systems with an electronic voltmeter for two channels, therefore, the earth should be connected particularly.

7. In the case of BTL connection amplifier, the minus terminal of speaker is not for earthing. Therefore, be sure not to connect any other earth terminal to this terminal. This system is of an OTL system.

1-28

Arrangement of adjusting positions

MX-G950V/MX-G880V MX-G850V/MX-G750V

Cassette mechanism section (Mechanism A section)

Head azimuth

adjusting screw

(Forward side)

Playback

head

Head azimuth

adjusting screw

(Reverse side)

Cassette mechanism section (Back side)

Head azimuth

adjusting screw

(Forward side)

Playback, recording and eraser

heads or playback head

Head azimuth

adjusting screw

(Reverse side)

Cassette Mechanism Unit Section

Tape speed ADJ

Bias ADJ L

Bias ADJ R

1-29

MX-G950V/MX-G880V MX-G850V/MX-G750V

Tape recorder section

Items Measurement

Confirmation of head angle

Confirmation of tape speed

conditions

Test tape :VT710 (10kHz) Measurement output terminal :Speaker terminal Speaker R (Load resistor:6 ) :Headphone terminal

Test tape :VT712 (3kHz) or TMT7036 (3kHz) Measurement output terminal :Headphone terminal

1.Playback the test tape VT710 (10kHz).

2.With the playback mechanism or recording & playback mechanism, adjust the head azimuth screw so that the forward and reverse output levels become maximum.After adjustment,lock the head azimuth at least by half a turn.

3.In either case,this adjustment should be performed in both the forward and reverse directions with the head azimuth screw.

<Constant speed> Adjust VR301 so that the frequency counter reading becomes 3,000Hz 60Hz when playing back the test tape VT712 (3kHz)with the playback mechanism or playback and recording mechanism after ending forward winding of the tape.

Reference values for confirmation items

Items Measurement

Double tape speed

conditions

Test tape :VT712 (3kHz) Measurement output terminal :Speaker terminal Speaker R (Load resistance:6 ) measurement output terminal :Headphone terminal

After setting to the double speed motor, confirm that the frequency counter reading becomes 4,800+400/-300Hz when the test tape VT712 (3kHz) has been play back with the playback mechanism.

Measurement method

Standard

values

Maximum output

Tape speed of decks (A and B) :3,000Hz 60Hz

Standard

values

4,800+400/

-300Hz

Adjusting

positions

Adjust the head azimuth screw only when the head has been changed.

VR301

Adjusting

positions

Playback mechanism side

Difference between the forward and reverse speed. P.mecha and R/P mecha speed

Wow & flutter

1-30

Test tape :VT712 (3kHz) Measurement output terminal :Headphone terminal

When the test tape VT712 (3kHz) has been played back with the playback mechanism or recording and playback mechanism at the beginning of forward winding, the frequency counter reading of the difference between both of the mechanisms should be 6.0Hz or less.

When the test tape VT712 (3kHz) has been played back with the playback mechanism or recording and playback mechanism at the beginning of forward winding the frequency counter reading of wow & flutter should be 0.25% or less(WRMS).

60Hz or less

with in

0.25% JIS(WTD)

Both the playback and recording & playback mechanism

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