JVC UXM-55 Service manual

SERVICE MANUAL

MICRO COMPONENT SYSTEM

UX-M55

Area suffix

E ----------- Continental Europe EN ------------ Northern Europe

UX-M55

STANDBY/ON

TUNER

TAPE

/BAND

/REV.MODE

/RANDOM

PRE DOWN PRE UP

REC

REMAIN

REPEAT

SLEEP

/RDS MODE

ST/MONO

INTRO

TIMER PROGRAM

/RDS SEARCH

PRE EQ

DISPLAY

/HBS

MODE

VOLUME

MUTING BEAT CUT

RM-SUXM5R REMOTE CONTROL

SP-UXM5

Contents

Safety precautions Preventing static electricity Important for laser products Disassembly method Adjustment method Flow of functional operation until TOC read

CD-R/RW PLAYBACK

MICRO COMPONENT SYSTEM UX-M55

STANDBY

/ON

DISPLAY

MODE

TIMER

ON/OFF

SET

RANDOM

PROGRAM

ST/MONO

STOP/CLEAR

REPEAT

PHONES

DIRECTION PLAY/PAUSE

REC

AUTO REVERSE

FULL LOGIC DECK

BAND REV. MODE

TUNER TAPE

SEARCH/TUNING

PRESET

OPEN/ CLOSE

REMAIN

/RDS MODE

INTRO/RDS SEARCH

VOLUME

PRE EQ

/HBS

EJECT

CA-UXM55 SP-UXM5

1-2 1-3 1-4 1-5 1-15

Maintenance of laser pickup Replacement of laser pickup Trouble shooting Description of major ICs Wiring connections

1-18

1-19 1-19 1-20 1-21 1-35

No.21190

Jan. 2003

UX-M55

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

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

Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as CD players. 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

UX-M55

Conductive material (conductive sheet) or iron plate

3. Handling the optical pickup

In order to maintain quality during transport and before installation, both sides of the laser diode on the

1. replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.)

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

2. source can easily destroy the laser diode.

4. Handling the traverse unit (optical pickup)

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

Remove solder of the short land on the card wire 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.

Handle the card wire carefully as it may break when subjected to strong force.

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

5. Attention when traverse unit is decomposed

Connector

*Please refer to "Disassembly method" in the text for the CD pickup unit.

Short land

Apply solder to the short land before the card wire is disconnected from the connector on the CD pickup unit. (If the card wire is disconnected without applying solder, the CD pickup may be destroyed by static electricity.) In the assembly, be sure to remove solder from the short land after connecting the card wire.

CD pickup unit

1-3

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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 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

CLASS 1 LASER PRODUCT

WARNING LABEL

1-4

Disassembly method

Replacement of the fuses and power amplifier IC

Replacing the fuses (See Fig. 1.)

Remove the left side plate according to its disassembly method (see Figs. 6 and 7).

Fuses are located inside the left side plate.

[Caution] Be sure to replace the required fuses with designated ones.

Fuse(F904)

1.6A 250V Fuse(F903)

2.5A 250V

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Power board

Fuse(F901)

1.6A 250V

Fuse(F902)

2.5A 250V

Replacing the power amplifier IC on

the main board (See Figs. 2 and 3.)

Remove the main board according to its disassembly method. (See Figs. 18 and 19.)

From the reverse side of the main board, remove the two screws A retaining the bracket.

(See Fig.2.)

From the forward side of the main board, remove the four screws B retaining the bracket.

(See Fig.3.)

Remove the screw C attaching the power amplifier IC onto the heat sink. (See Fig.3.)

In order to replace the power amplifier IC, remove the solder from the soldered part a on the reverse side of the main board. (See Fig.3.)

Soldered part a

Heat sink

Fig.1

Main board (Reverse side)

Fig.2

Main board

Power amplifier IC

(IC402)

Bracket

Fig.3

1-5

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Removing the right side plate

(See Figs. 4 and 5.)

1.2.From the right side of the main body, remove the three screws D and three screws E retaining the right side plate. (See Fig.4.)

Slide the right side plate toward the rear (in the direction of the arrow 1) until the claw b at the back of the right side plate is hooked by the bottom case and then lift the right side plate upward (in the direction of the arrow 2) to remove it. (See Fig.5.)

Removing the left side plate

(See Figs. 6 and 7.)

1.2.From the left side of the main body, remove the

three screws D and three screws E retaining the left side plate. (See Fig.6.)

Right side plate

Fig.4

Right side plate

Slide the left side plate toward the rear (in the direction of the arrow 3) until the claw c at the back of the left side plate is hooked by the bottom case, and then lift the left side plate upward (in the direction of the arrow 4) to remove it. (See Fig.7.)

Left side plate

Bottom case

Left side plate

Claw b

Fig.5

1-6

Fig.6

Fig.7

Claw c

Bottom case

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Removing the top cabinet

(See Figs. 8 and 9.)

Remove the left and right side plates.

1.2.From the back side of the main body, loosen the two screws F retaining the top cabinet. (See Fig.8.)

Lift the rear part of the top cabinet to remove it.

(See Fig.9.)

Removing the front cabinet assembly

(See Figs. 10 to 12.)

Remove the left and right side plates. Remove the top cabinet.

From the left side of the main body, remove the tie band bundling the wires. (See Fig.10.)

Disconnect the wire from the connector on the cassette switch board. (See Fig.10.)

Remove the screw G retaining the holder on the earphone board. (See Fig.10.)

Disconnect the wires from the two connectors CN607 and CN608 on the CD & MCU board.

(See Figs.10 and 11.)

Lift the rear part to remove.

Fig.8

(To be loosened)

Top cabinet

Rear cabinet

Remove the four screws H and the two screws J retaining the CD mechanism assembly from the left and right. (See Figs.10 and 11.)

Remove the screw K retaining the front cabinet assembly from the bottom side of the main body.

While opening the hooks d to the left and right of the lower part of the front cabinet assembly (in the direction of the arrows 1), slide the front cabinet assembly toward the front (in the direction of the arrow 2). (See Fig.12.)

Disconnect the wire from the connector on the PB/REC head board, and then remove the front cabinet assembly. (See Fig.10.)

[Note] After assembly, apply a locking agent to the screws G, H and J.

(See Fig.12.)

CD mechanism assembly

CD & MCU board

Connector on the cassette switch board

Bottom case

Fig.9

Power board

Fig.10

Hook d

Tie band

Connector on the PB/REC head board

Front cabinet assembly

CN608

J G

Earphone board

Holder

CN607

CD & MCU board

Fig.11

Hook d

Fig.12

1-7

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Removing the CD mechanism

assembly (See Figs. 13 to 15.)

Remove the left and right side plates. Remove the top cabinet. Remove the front cabinet assembly.

From the top side of the main body, disconnect the wires from the four connectors CN601, CN602, CN603 and CN701 on the CD & MCU board.

(See Fig.13.)

From the left side of the main body, remove the tie bands bundling the wires. (See Fig.14.)

Disconnect the wire from the connector CN902 on the power board. (See Fig.14.)

From the left and right sides of the main body, remove the four screws L retaining the CD rear mounting bracket. (See Figs.14 and 15.)

Slide the CD mechanism assembly toward the front (in the direction of the arrow) and remove it from the locking board support of the main board.

(See Fig.15.)

CN603

CN701

CD & MCU board

CD rear mounting bracket

CN601

CN602

CD mechanism assembly

Fig.13

Tie bands

CN902

Power board

Fig.14

Removing the power board

(See Figs. 16 and 17.)

Remove the left and right side plates.

Disconnect the wires from the connector CN901 on the power board. (See Fig.16.)

Remove the tie bands bundling the wires.

(See Fig.16.)

Remove the screw M retaining the lug wire.

(See Fig.16.)

Remove the two screws N retaining the bottom case. (See Fig.16.)

Remove the power board by pinching the two locking board supports retaining the power board using radio pliers, etc. (See Fig.17.)

Radio pliers, etc.

Power board

Locking board support

Locking board supports

Power transformer

CD & MCU board

Fig.15

Main board

CN901

Tie bands

Lug wire

1-8

Fig.17

Bottom case

Fig.16

Power board

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Removing the main board

(See Figs. 18 and 19.)

Remove the left and right side plates. Remove the top cabinet. Remove the front cabinet assembly. Remove the CD mechanism assembly.

From the inside of the main body, remove the five screws P retaining the bracket. (See Fig.18.)

From the top side of the main body, remove the wires from the connectors CN104 and CN106 on the AM and FM antenna boards. (See Fig.19.)

From the rear side of the main body, remove the two screws Q and three screws R retaining the rear cabinet. (See Fig.18.)

Remove the screw S and screw S' retaining the FM antenna board and earth wire. (See Fig.18.)

[Note] When attaching the screw S', attach the earth wire together the FM antenna board.

Remove the rear cabinet.

AM antenna board

Heat sink

S P

Rear cabinet

Fig.18

Regulator IC

(IC302)

Main board

Locking board support

CN901

From the top side of the main body, remove the wire clamp bundling the wires. (See Fig.19.)

Remove the screw T retaining the bracket of the main board. (See Fig.19.)

Remove the screw U retaining the regulator IC(IC302). (See Fig.19.)

Remove the tie bands bundling the wires.

(See Fig.19.)

10.

Disconnect the wire from the connector CN901 on the power board. (See Fig.19.)

11.

Remove the locking board support on the main board, and then take out the main board from the bottom case. (See Fig.19.)

CN104

Wire clamp

Earth wire

FM antenna board

Bracket

CN106

Bottom case

Power board

Tie bands

Fig.19

1-9

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Remove the left and right side plates. Remove the top cabinet. Remove the front cabinet assembly.

Removing the key board (See Fig. 20.)

Remove the ten screws V retaining the key board.

Removing the cassette mechanism assembly (See Fig.20.)

Remove the two screws W and the two screws X retaining the cassette mechanism assembly.

[Note] After assembly, apply a locking agent to the screws W and X.

Front cabinet assembly

Latching cam assembly

Key board

Cassette mechanism assembly

Removing the damp gear (See Fig. 20.)

Remove the screw Y retaining the damping gear holder and take out the damp gear.

[Note] After assembly, apply a locking agent to the screw Y.

Removing the latching cam assembly

(See Fig.20.)

Remove the two screws Z retaining the latching cam assembly and remove the latching cam assembly.

[Note] After assembly, apply a locking agent to the screw Z.

Removing the cassette door cover

(See Fig.21.)

[Note] Use the following procedure to remove only the cassette door cover. This procedure does not require the removal of exterior parts such as the side panels.

Damping gear holder

Damp gear

Technical door

Claw e

Fig.20

1.2.Open the cassette door.

Slide the cassette door cover in the direction of the arrow, and disengage the two claws e and the two claws f on the left and right of the cassette door cover from the technical door.

1-10

Claw f

Cassette door cover

Fig.21

Removing the technical door (See Figs. 22 and 23.)

Remove the cassette mechanism assembly. Remove the cassette door cover.

Open the technical door, disengage the cassette torsion spring hooked across the front of the front cabinet assembly and the technical door in the outward direction, and remove it from the claw g.

(See Fig.22.)

From the back side of the front cabinet assembly, remove the two screws AA retaining the logic deck bracket. (See Fig.23.)

While pushing the arm section h of the technical door in the direction of the arrow, remove the shaft section i of the technical door from the front cabinet assembly. (See Fig.23.)

While pushing the arm section j of the technical door in the direction of the arrow, remove the shaft section k of the technical door from the front cabinet assembly. (See Fig.23.)

Arm section h

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Front cabinet assembly

Technical door

Cassette torsion spring

Claw g

Disengage the cassette torsion spring so that it comes to the front of the claw g.

Fig.22

Front cabinet assembly

Technical door

Take out the technical door from the back side of the front cabinet assembly.

[Caution] In the assembly, be sure to put the cassette torsion spring around the shaft section i before attaching the technical door.

[Note] After assembly, apply a locking agent to the screws AA.

Shaft section i

Cassette torsion spring

Arm section j

Shaft section k

Logic deck bracket

Fig.23

1-11

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Remove the left and right side plates. Remove the top cabinet. Remove the front cabinet assembly. Remove the CD mechanism assembly.

Removing the CD & MCU board (See Figs. 1 and 2.)

From the bottom side of the CD mechanism assembly, remove the two screws A retaining the CD & MCU board. (See Fig.1.)

Disengage the two locking board supports retaining the CD & MCU board. (See Fig.1.)

Disconnect the wires from the two connectors CN702 and CN703 on the CD & MCU board.

(See Figs.1 and 2.)

Lift the CD & MCU board and attach solder to the short land part a on the CD pickup assembly.

(See Fig.2.)

Locking board support

CD & MCU board

CN702

Fig.1

CN704

CD pickup unit

Disconnect the card wire from the connector CN704 on the CD & MCU board, and take out the CD & MCU board. (See Fig.2.)

[Cautions] Be sure to solder the short land part a on the CD pickup unit before disconnecting the card wire from the CD pickup unit. (See Fig. 2.) If the card wire is disconnected without attaching solder, the CD pickup may be destroyed by static electricity. In the assembly, be sure to remove solder from the short land part a after connecting the card wire.

Removing the CD pickup assembly (See Fig. 3.)

Remove the CD & MCU board.

CN703

CD pickup assembly

CD mechanism assembly

CD pickup assembly

Damper(Gray)

Short land part a

Fig.2

Damper(Blue)

From the back side of the CD mechanism assembly, remove the four screws B retaining the CD pickup assembly.

Take out the CD pickup assembly.

[Note] When removing or replacing the dampers, note their colors and be sure to attach them in their correct positions.

1-12

Damper(Blue)Damper(Gray)

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Removing the tray motor (See Figs. 4 to 7.)

Remove the CD & MCU board.

From the top side of the CD mechanism assembly, open up the claws b and c at the left and right of the clamper assembly and lift the assembly to remove it. (See Fig.4.)

Push the section d of the elevator in the direction of the arrow and lower the CD pickup assembly.

(See Fig.5.)

Pull out the tray. (See Fig.5.)

While opening up the claws e at the left and right of the tray in the directions of the arrows, remove the tray. (See Fig.6.)

While pushing the claw f on the CD mechanism assembly downwards, slide the elevator fully in the direction of the arrow. (See Fig.7.)

Lift the gear slightly, remove the transparent cover.

(See Fig.7.)

CD mechanism assembly

Claw b

Claw c

Fig.4

Clamper assembly

Claw c

Tray

Remove the belt from the tray motor pulley.

(See Fig.7.)

Remove the two screws C retaining the tray motor and remove it from the bottom side of the CD mechanism assembly. (See Fig.7.)

[Notes] Take care not to attach grease on the belt. After attaching the tray motor in the assembly, apply a locking agent to the screws C.

CD pickup assembly

Tray motor pulley

Fig.5

Section d

TrayClaw e

Claw e

Fig.6

CD mechanism assembly

Claw f

Tray motor

Fig.7

Transparent

Belt

Gear

cover

1-13

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Replacing the CD pickup unit (See Figs. 8 to 11.)

[Note] Use the following procedure to replace only the CD pickup unit.

Remove the left and right side plates. (See Figs. 4 to 7 of "Main body section" on page 1-7.)

Remove the top cabinet. (See Figs. 8 and 9 of "Main body section" on page 1-8.)

From the top side of the main body, open up the claws b and c on the left and right of the clamper assembly in the direction of the arrows and lift the assembly to remove it. (See Fig.8.)

Push the section d on the elevator of the CD mechanism assembly and lower the CD pickup assembly. (See Fig.9.)

Pull out the tray. (See Fig.10.)

Remove the slit washer retaining the feed middle gear, and take out the feed middle gear.

(See Fig.10.)

Clamper assembly

Claw c

Claw b

Front cabinet assembly

Claw c

Fig.8

Front cabinet assembly

Loosen the two screws D retaining the shaft.

(See Fig.10.)

Turn the CD pickup unit upside down and apply solder to the short land part a. (See Fig.11.)

Disconnect the card wire from the CD pickup unit and replace the unit. (See Fig.11.)

[Cautions] Be sure to solder the short land part a on the CD pickup unit before disconnecting the card wire from the CD pickup unit. (See Fig. 11.) If the card wire is disconnected without attaching solder, the CD pickup may be destroyed by static electricity. In the assembly, be sure to remove solder from the short land part a after connecting the card wire.

[Note] Removing the CD pickup unit involves the removal of the sliding spring. In the assembly, be sure to attach the spring in the correct orientation before attaching the CD pickup unit. (See Fig. 11.)

Feed middle gear

Sliding spring

(To be loosened)

Slit washer

Card wire

Section d

Fig.9

CD pickup assembly

(To be loosened)

Fig.10

Tray

1-14

Short land part a

.11

Adjustment method

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Measuring instructions required for adjustment

1. AM signal generator

2. FM signal generator

3. Inter mediate frequency sweep generator

4. FM stereo signal generator

5. Low-frequency oscillator (oscillation frequency 50Hz-20kHz, 0dB output with 600 ohm impedance)

6. Attenuator (600 ohm impedance)

7. Electronic voltmeter

8. Distortion meter

9. Torque gauge (cassette for CTG-N)

10. Wow & flutter meter

11. Frequency counter meter

12. Test tape VT712 : For tape speed and wow flutter VT724 : For reference level VT702 : For playback frequency VT702 : For head azimuth adjustment

13. Blank tape TAPE : AC-225

Measuring instruments

Radio section FM 1kHz, 22.5kHz deviation FM STEREO : 1kHz, 67.5kHz deviation pilot signal 7.5kHz AM : 1kHz, 30% modulation Reference output : Speaker output 0dBs(2.8V) 8 ohm PHONES output -10dBs(0.245V)/32 ohm

Cassette amplifier section Reference output : Speaker output 0dBs(2.8V) 8 ohm PHONES output -10dBs(0.245V)/32 ohm

CD section CD test disc : CTS-1000

Measurement conditions

Power supply voltage AC220~240V(50Hz/60Hz)

1-15

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Cassette amplifier section

Item Measuring condition Check and adjustment procedure Standard value Adjusting part Head azimuth adjustment

Tape speed and wow/flutter check and adjustment

PB frequency response check

Bias frequency check

REC and PB frequency response adjustment

Test tape: VT702 (8kHz) Signal output terminal: PHONES output (with 32 ohm load)

Test tape: VT712 (3kHz) Signal output terminal: PHONES output (with 32 ohm load)

Test tape: VT702 Signal output terminal: PHONES output (with 32 ohm load) Tape: Normal Signal output terminal: Cassette REC./PLAY HEAD Test tape: AC225 Signal input: FM22.5 DEV 60dBµ with emphasis Signal output terminal: PHONES output (with 32 ohm load)

Play back the test tape VT702 (8kHz).

1. Adjust the head azimuth adjusting screw so that the

2. phase difference between the R and L channels is minimized at an output level that is within +2dB-2dB of the maximum output level. After this adjustment, lock the head azimuth adjusting screw with screw sealant to cover more than a half of the screw head.

When the head azimuth is maladjusted, correct it with the head azimuth adjusting screw. Play back the test tape VT712 (3kHz) by the end

1. portion. Connect a frequency counter and check that it reads

2. between 2940 and 3090Hz. If not, adjust the frequency with the motor semifixed resistor. Check that the wow/flutter is within 0.38%

3. (unweighted).

Play back the test tape VT702 while con-firming that deviation between the 1kHz signal and 8kHz signal should be (0+3dB-6dB).

Set the TUNER or CD function and with TAPE to record. Check to see if the frequency at the measuring point P201 is 68kHz+1kHz-1kHz if not adjust L203 until the frequency counter indicates 68 kHz+1kHz-1kHz. At TUNER, set the BAND to the FM position, and record the reference 1kHz signal and 8kHz signal alternately repeatedly. While playing back the recorded signal differ from that of the 1kHz signal by within (0+3dB-6dB).

Output level: Within +2dB-2dB of maximum output level Phase difference R and L channels: Minimum

2940 to 3090Hz

Within 0.38% (unweighted)

Deviation between 1kHz and 8kHz: (0+3dB-6dB)

Level difference between REC and PB: Within (0+3dB-6dB)

Head azimuth adjusting screw (To be used only after head replacement) See Fig.1 on page 1-17.

Tape speed: Motor semifixed resistor

See Fig.2 on page 1-17. Check only

L203, P201 See Fig.3 on page 1-17.

Tuner section

Item Measuring condition Check and adjustment procedure Standard value Adjusting part

AM IF adjustment 1.

AM tracking adjustment

Tuner 114kHz Filter the waves adjustment

Signal input: Loop antenna Signal output: IC101 pin18

Signal input: Loop antenna Signal output: PHONES output (with 32 ohm load)

Signal input: IC101 pin19 Signal output: IC101 pin18

Set the intermediate frequency sweep generator to AM 450kHz. Adjust the T101 for maximum and center output.

2. T101

Set the TUNER at 522kHz adjust L102 until the test

1. pin of R121 voltage at 1.7V+0.1V-0.1V. Set the TUNER at 1629kHz, check the test pin of R121

2. voltage at 8.0V+0.3V-0.3V. Set the TUNER and S/G at 612kHz, adjust L103 for

3. maximum output. Set the TUNER and S/G at 1404kHz, adjust the TC101

4. for maximum output. Repeat the above steps 3 and 4.

Set standby and input 114kHz signal to IC101 pin19.

Adjust the L104 for output voltage minimum.

2. L104

See Fig.3 on page 1-17.

L102

L103

TC101 See Fig.3 on page 1-17.

See Fig.3 on page 1-17.

1-16

Location of adjusting parts

Cassette mechanism section

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Main board

Fig.1 Head output signal

(AM VT)

R121

T101

(AM IF)

L104

(114kHz)

IC101

TA2099

CASSETTE MOTOR

Tape Speed Adj.

Fig.2

L103

(AM RF)

L102

(AM OSC)

TC101

(AM RF)

P201

(BIAS FREQUENCY)

L203

(BIAS FREQUENCY ADJ.)

Fig.3

1-17

UX-M55

Flow of functional operation until TOC read

Power ON

Slider turns REST SW ON.

Laser ON

Focus start

FOK

Turn on focus servo

Confirm that the voltage at the pin5 of CN703 is "H"/"L"/"H"

Check that the voltage at the pin10(LD) of CN704 is +1.35V.

Caution

Before connecting a measuring instrument to the measuring point, turn the power of the main unit to OFF. After performing a measurement and before disconnecting the measuring instrument, again turn the power of the main unit to OFF. (If a measuring instrument is disconnected while an electric current is being output to the main unit, the pick up of the main unit will be damaged.)

Disc spinning

Radial_error scaling

PLL Lock

Turn on radial servo

Read TOC

Check that the voltage at the pin1 and pin2 of CN703 is +0.65V.

Confirm the eye-pattern at the "RFO" test point. (Refer to "Printed circuit boards" section.)

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UX-M55

Maintenance of laser pickup

(1) Cleaning the pick up lens Before you replace the pick up, please try to clean the lens with a alcohol soaked cotton swab.

(2) Life of the laser diode When the life of the laser diode has expired, the following symptoms will appear.

The level of RF output (EFM output:ampli tude of eye pattern) will below.

Is the level of

RF OUT under

1.25V 0.22Vp-p?

YES

O.K

Replace it.

Replacement of laser pickup

Turn off the power switch and, disconnect the power cord from the AC OUTLET.

Replace the pickup with a normal one. (Refer to "Removing the CD pickup" on the previous page)

Plug the power cord in, and turn the power on. At this time, check that the laser emits for about 3 seconds and the objective lens moves up and down. Note: Do not observe the laser beam directly.

Play a disc.

Check the eye-pattern at the "RFO" test point. (Refer to "Printed circuit boards" section.)

Finish.

(3) Semi-fixed resistor on the APC PC board The semi-fixed resistor on the APC printed circuit board which is attached to the pickup is used to adjust the laser power. Since this adjustment should be performed to match the characteristics of the whole optical block, do not touch the semi-fixed resistor. If the laser power is lower than the specified value, the laser diode is almost worn out, and the laser pickup should be replaced. If the semi-fixed resistor would be adjusted when the pickup operates normally, the laser pickup may be damaged due to excessive current.

1-19

+ 44 hidden pages

JVC UXM-55 Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual