JVC Micro Component System UX-M55 User manual

UX-M55
No.21190
Jan. 2003
COPYRIGHT 2002 VICTOR COMPANY OF JAPAN, LTD.
SERVICE MANUAL
Contents
Safety precautions
Preventing static electricity
Important for laser products
Disassembly method
Adjustment method
Flow of functional operation
until TOC read
1-2
1-3
1-4
1-5
1-15
1-18
1-19
1-19
1-20
1-21
1-35
Maintenance of laser pickup
Replacement of laser pickup
Trouble shooting
Description of major ICs
Wiring connections
UX-M55
Area suffix
E ----------- Continental Europe
EN ------------ Northern Europe
SP-UXM5 CA-UXM55 SP-UXM5
MICRO COMPONENT SYSTEM
DISPLAY
MODE
PHONES
PROGRAM
REC DIRECTION PLAY/PAUSE
PRE EQ
/HBS
VOLUM E
REPEAT
SEARCH/TUNING
RANDOM
CD TUNER TAPE
BAND REV.MODE
MICRO COMPONENT SYSTEM UX-M55
AUTO REVERSE
FULL LOGIC DECK
TIMER
ON/OFF
SET
REMAIN
/RDS MODE
EJECT
INTRO/RDS
SEARCH
OPEN/
CLOSE
STANDBY
/ON
ST/MONO STOP/CLEAR
PRESET
CD-R/RW PLAYBACK
CD /RANDOM
DISPLAY
MODE
REC
SLEEP
TIMER PROGRAM
MUTING BEAT CUT
PRE EQ
/HBS
STANDBY/ON
+
VOLUME
Ð
TUNER
/BAND TAPE /REV.MODE
INTRO
/RDS SEARCH
REMAIN
/RDS MODE
REPEAT
ST/MONO
RM-SUXM5R REMOTE CONTROL
PRE DOWN PRE UP

UX-M55
1-2
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.).
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.
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500 10W
0.15 F AC TYPE
!
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.)

UX-M55
1-3
Short land
CD pickup unit
Connector
Conductive material
(conductive sheet) or iron plate
(caption)
Anti-static wrist strap
5. Attention when traverse unit is decomposed
*Please refer to "Disassembly method" in the text for the CD pickup unit.
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.
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.
Preventing static electricity
1. Grounding to prevent damage 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. About the earth processing for the destruction prevention by static electricity
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.
2-1 Ground the workbench
2-2 Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
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.)
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.
3. Handling the optical pickup
1.
2.
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.
4. Handling the traverse unit (optical pickup)
1.
2.
3.
4.

UX-M55
1-4
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.
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.
VARNING : Osynlig laserstrålning är denna del är öppnad
och spårren är urkopplad. Betrakta ej strålen.
VARO : Avattaessa ja suojalukitus ohitettaessa olet
alttiina näkymättömälle lasersäteilylle.Älä katso
säteeseen.
ADVARSEL : Usynlig laserstråling ved åbning , når
sikkerhedsafbrydere er ude af funktion. Undgå
udsættelse for stråling.
ADVARSEL : Usynlig laserstråling ved åpning,når
sikkerhetsbryteren er avslott. unngå utsettelse
for stråling.
REPRODUCTION AND POSITION OF LABELS
WARNING LABEL
!CAUTION Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
CLASS 1
LASER PRODUCT

UX-M55
1-5
Fi
g
.3
Fig.1
Fig.2
Fuse(F904)
1.6A 250V
Fuse(F901)
1.6A 250V
Power board
Fuse(F903)
2.5A 250V
A
Main board (Reverse side)
B
C
Soldered part a
Heat sink
Bracket
Power amplifier IC
(IC402)
Main board
Fuse(F902)
2.5A 250V
Replacing the fuses (See Fig. 1.)
<Main body section>
Remove the left side plate according to its
disassembly method (see Figs. 6 and 7).
Fuses are located inside the left side plate.
Disassembly method
Replacement of the fuses and power amplifier IC
[Caution] Be sure to replace the required fuses
with designated ones.
Replacing the power amplifier IC on
the main board (See Figs. 2 and 3.)
1.
2.
3.
4.
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 Aretaining the bracket.
(See Fig.2.)
From the forward side of the main board, remove
the four screws Bretaining the bracket.
(See Fig.3.)
Remove the screw Cattaching 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 aon the reverse
side of the main board. (See Fig.3.)

UX-M55
1-6
1
3
2
4
D
D
E
E
Right side
plate
Right side
plate
Claw b
Left side
plate
Claw c
Fi
g
.6
D
D
E
E
Left side
plate
Fi
g
.7
Fig.5
Fig.4
Bottom case
Bottom case
Removing the right side plate
(See Figs. 4 and 5.)
1.
2.
From the right side of the main body, remove the
three screws Dand three screws Eretaining 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 bat 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 Dand three screws Eretaining the
left side plate. (See Fig.6.)
Slide the left side plate toward the rear (in the
direction of the arrow 3) until the claw cat 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.)

UX-M55
1-7
1
2
1
F
Top cabinet
(To be loosened)
Rear cabinet
F
Fig.9
Fig.8
Lift the rear
part to remove.
Fig.10
K
Fi
g
.12
Front cabinet assembly
Hook d
Hook d
Bottom case
Fi
g
.11
H
J
CD mechanism
assembly
CN607
Holder
Earphone
board
Connector on the
cassette switch
board
Connector on the
PB/REC head board
Power board
Tie band
CN608
CD mechanism
assembly H
H
J
G
CD & MCU board
CD & MCU board
Removing the top cabinet
(See Figs. 8 and 9.)
1.
2.
From the back side of the main body, loosen the
two screws Fretaining 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.)
1.
2.
3.
4.
5.
6.
7.
8.
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 Gretaining 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.)
Remove the four screws Hand the two screws J
retaining the CD mechanism assembly from the left
and right. (See Figs.10 and 11.)
Remove the screw Kretaining the front cabinet
assembly from the bottom side of the main body.
(See Fig.12.)
While opening the hooks dto 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.)
Remove the left and right side plates.
Remove the left and right side plates.
Remove the top cabinet.
[Note] After assembly, apply a locking agent to
the screws G, H and J.

UX-M55
1-8
Fig.13
L
Fig.14
CD & MCU board CD mechanism assembly
CD & MCU board
CD & MCU board
CN603
CN701
Tie bands
L
Fig.15
Main board
CN601
CN602
Locking board
support
CN902
Power board
CN901
Main board
Locking board supports
Power transformer
Tie bands
Power board
Lug wire
Fi
g
.16
NM
Bottom case
Locking board support
Radio pliers, etc.
Power board
Fi
g
.17
Bottom case
CD rear mounting bracket
Removing the CD mechanism
assembly (See Figs. 13 to 15.)
1.
2.
3.
4.
5.
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 Lretaining 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.)
Removing the power board
(See Figs. 16 and 17.)
1.
2.
3.
4.
5.
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 Mretaining the lug wire.
(See Fig.16.)
Remove the two screws Nretaining 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.)

UX-M55
1-9
Fig.18
Fig.19
P
R
P
QR
TU
Bottom case
Tie bands
CN901
Power board
Main board
Regulator IC
(IC302)
Heat sink
AM antenna board Locking board support
Bracket
S
S'
Rear cabinet
FM antenna board
CN106
CN104
Wire clamp
Earth wire
Removing the main board
(See Figs. 18 and 19.)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
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 Pretaining 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 Qand three screws Rretaining the rear
cabinet. (See Fig.18.)
Remove the screw Sand screw S' retaining the FM
antenna board and earth wire. (See Fig.18.)
Remove the rear cabinet.
From the top side of the main body, remove the
wire clamp bundling the wires. (See Fig.19.)
Remove the screw Tretaining the bracket of the
main board. (See Fig.19.)
Remove the screw Uretaining the regulator
IC(IC302). (See Fig.19.)
Remove the tie bands bundling the wires.
(See Fig.19.)
Disconnect the wire from the connector CN901 on
the power board. (See Fig.19.)
Remove the locking board support on the main
board, and then take out the main board from the
bottom case. (See Fig.19.)
[Note] When attaching the screw S', attach the
earth wire together the FM antenna
board.

UX-M55
1-10
Fig.20
X
V
Z
Y
V
W
Front cabinet assembly
Latching
cam assembly
Damp gear
Cassette
mechanism
assembly
Damping gear holder
Key board
X
Fi
g
.21
Technical door
Claw e
Claw f
Cassette door cover
Removing the key board (See Fig. 20.)
Remove the ten screws Vretaining the key board.
Remove the left and right side plates.
Remove the top cabinet.
Remove the front cabinet assembly.
[Note] After assembly, apply a locking agent
to the screws W and X.
<Front cabinet assembly section>
Remove the two screws Wand the two screws X
retaining the cassette mechanism assembly.
Remove the screw Yretaining the damping gear
holder and take out the damp gear.
Remove the two screws Zretaining the latching
cam assembly and remove the latching cam
assembly.
1.
2.
Open the cassette door.
Slide the cassette door cover in the direction of
the arrow, and disengage the two claws eand the
two claws fon the left and right of the cassette
door cover from the technical door.
[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.
[Note] After assembly, apply a locking agent
to the screw Z.
Removing the cassette mechanism
assembly (See Fig.20.)
Removing the latching cam assembly
(See Fig.20.)
Removing the damp gear (See Fig. 20.)
Removing the cassette door cover
(See Fig.21.)
[Note] After assembly, apply a locking agent
to the screw Y.

UX-M55
1-11
Fig.22
Claw g
Disengage the cassette
torsion spring so that it
comes to the front of the
claw g.
Front cabinet assembly
Cassette torsion spring
Technical door
Fig.23
AA
Front cabinet assembly
Arm section h
Arm section j
Shaft section i
Cassette torsion spring
Shaft section k
Logic deck bracket
Technical door
1.
2.
3.
4.
5.
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 hof the technical
door in the direction of the arrow, remove the shaft
section iof the technical door from the front
cabinet assembly. (See Fig.23.)
While pushing the arm section jof the technical
door in the direction of the arrow, remove the shaft
section kof the technical door from the front
cabinet assembly. (See Fig.23.)
Take out the technical door from the back side of
the front cabinet assembly.
Remove the cassette mechanism assembly.
Remove the cassette door cover.
[Caution] In the assembly, be sure to put the
cassette torsion spring around
the shaft section i before attaching
the technical door.
Removing the technical door
(See Figs. 22 and 23.)
[Note] After assembly, apply a locking agent
to the screws AA.

UX-M55
1-12
Fig.1
Fig.2
Fi
g
.3
A
A
CD & MCU board
Locking board support
Locking board support
CD & MCU board
CD mechanism assembly
CD pickup assembly Damper(Blue)
CD pickup unit
B
CN704
B
Damper(Gray)
Damper(Blue)Damper(Gray)
CD pickup
assembly
Short land part a
CN703
CN702
Removing the CD & MCU board
(See Figs. 1 and 2.)
1.
2.
3.
4.
5.
From the bottom side of the CD mechanism
assembly, remove the two screws Aretaining 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 aon the CD pickup assembly.
(See Fig.2.)
Disconnect the card wire from the connector
CN704 on the CD & MCU board, and take out the
CD & MCU board. (See Fig.2.)
Remove the left and right side plates.
Remove the top cabinet.
Remove the front cabinet assembly.
Remove the CD mechanism assembly.
<CD mechanism section>
Removing the CD pickup assembly
(See Fig. 3.)
1.
2.
Remove the CD & MCU board.
From the back side of the CD mechanism
assembly, remove the four screws Bretaining 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.
[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.

UX-M55
1-13
Fig.4
Fig.5
Fig.6
Fig.7
C
CD mechanism assembly
Clamper assembly
Claw b
Claw c
CD mechanism assembly
Tray motor pulley
Claw c
Section d
Tray
TrayClaw e
Claw e
Claw f
Belt
Transparent cover
CD pickup assembly
Gear
Tray motor
Removing the tray motor
(See Figs. 4 to 7.)
1.
2.
3.
4.
5.
6.
7.
8.
Remove the CD & MCU board.
From the top side of the CD mechanism assembly,
open up the claws band cat the left and right of
the clamper assembly and lift the assembly to
remove it. (See Fig.4.)
Push the section dof 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 eat the left and right
of the tray in the directions of the arrows, remove
the tray. (See Fig.6.)
While pushing the claw fon 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.)
Remove the belt from the tray motor pulley.
(See Fig.7.)
Remove the two screws Cretaining 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.

UX-M55
1-14
Fig.8
Fig.9
Fig.10
Fi
g
.11
Clamper assembly Front cabinet assembly
Claw b
Claw c
D
DCD pickup assembly
Front cabinet assembly
Claw c
Section d
Tray
Slit washer
Feed middle gear
Card wire
Sliding spring
Short land part a
(To be loosened)
(To be loosened)
Replacing the CD pickup unit
(See Figs. 8 to 11.)
1.
2.
3.
4.
5.
6.
7.
8.
9.
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 9of
"Main body section" on page 1-8.)
From the top side of the main body, open up the
claws band con 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 don 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.)
Loosen the two screws Dretaining 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.)
[Note] Use the following procedure to replace
only the CD pickup unit.
[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.)

UX-M55
1-15
Adjustment method
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
Measurement conditions
Power supply voltage
AC220~240V(50Hz/60Hz)
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

UX-M55
1-16
Cassette amplifier section
Item Measuring condition Check and adjustment procedure Standard value Adjusting part
Play back the test tape VT702 (8kHz).
Adjust the head azimuth adjusting screw so that the
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.
Test tape:
VT702 (8kHz)
Signal output terminal:
PHONES output
(with 32 ohm load)
Head azimuth
adjustment
1.
2.
3.
Output level:
Within +2dB-2dB of
maximum output
level
Phase difference R
and L channels:
Minimum
Head azimuth
adjusting screw
(To be used only
after head
replacement)
See Fig.1 on
page 1-17.
Play back the test tape VT712 (3kHz) by the end
portion.
Connect a frequency counter and check that it reads
between 2940 and 3090Hz. If not, adjust the frequency
with the motor semifixed resistor.
Check that the wow/flutter is within 0.38%
(unweighted).
Test tape:
VT712 (3kHz)
Signal output terminal:
PHONES output
(with 32 ohm load)
Tape speed and
wow/flutter check
and adjustment
1.
2.
3.
2940 to 3090Hz
Within 0.38%
(unweighted)
Tape speed:
Motor semifixed
resistor
See Fig.2 on
page 1-17.
Check only
Play back the test tape VT702 while con-firming that
deviation between the 1kHz signal and 8kHz signal
should be (0+3dB-6dB).
Test tape: VT702
Signal output terminal:
PHONES output
(with 32 ohm load)
PB frequency
response check
Deviation between
1kHz and 8kHz:
(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.
Tape: Normal
Signal output terminal:
Cassette REC./PLAY
HEAD
Bias frequency
check
L203, P201
See Fig.3 on
page 1-17.
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).
Test tape: AC225
Signal input:
FM22.5 DEV 60dBµ
with emphasis
Signal output terminal:
PHONES output
(with 32 ohm load)
REC and PB
frequency
response
adjustment
Level difference
between REC and
PB: Within
(0+3dB-6dB)
Tuner section
Item Measuring condition Check and adjustment procedure Standard value Adjusting part
Set the intermediate frequency sweep generator to AM
450kHz.
Adjust the T101 for maximum and center output.
Signal input:
Loop antenna
Signal output:
IC101 pin18
AM IF adjustment 1.
2. T101
See Fig.3 on
page 1-17.
Set standby and input 114kHz signal to IC101 pin19.
Adjust the L104 for output voltage minimum.
Signal input:
IC101 pin19
Signal output:
IC101 pin18
Tuner 114kHz
Filter the waves
adjustment
1.
2. L104
See Fig.3 on
page 1-17.
Set the TUNER at 522kHz adjust L102 until the test
pin of R121 voltage at 1.7V+0.1V-0.1V.
Set the TUNER at 1629kHz, check the test pin of R121
voltage at 8.0V+0.3V-0.3V.
Set the TUNER and S/G at 612kHz, adjust L103 for
maximum output.
Set the TUNER and S/G at 1404kHz, adjust the TC101
for maximum output.
Repeat the above steps 3 and 4.
Signal input:
Loop antenna
Signal output:
PHONES output
(with 32 ohm load)
AM tracking
adjustment
1.
2.
3.
4.
5.
L102
L103
TC101
See Fig.3 on
page 1-17.

UX-M55
1-17
Fig.1 Head output signal
CASSETTE MOTOR
Tape Speed Adj.
+-
Location of adjusting parts
Cassette mechanism section
Fig.2
Main board
Fig.3
(AM VT)
R121 T101
(AM IF)
L104
(114kHz)
IC101
TA2099
L103
(AM RF)
TC101
(AM RF)
L102
(AM OSC)
P201
(BIAS FREQUENCY)
L203
(BIAS FREQUENCY ADJ.)

UX-M55
1-18
Flow of functional operation until TOC read
Power ON Slider turns REST
SW ON.
Laser ON
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.
Focus start
FOK
PLL Lock
Turn on radial
servo
Read TOC Confirm the eye-pattern at the "RFO" test point.
(Refer to "Printed circuit boards" section.)
Turn on focus
servo
Disc spinning
Radial_error
scaling
Check that the voltage at the pin1 and pin2 of
CN703 is +0.65V.
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.)
Caution

UX-M55
1-19
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.
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? Replace it.
NO
YES
O.K
(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.
Replacement of laser pickup

UX-M55
1-20
Trouble shooting
Circuit Symptom Cause
Speakers are not connected.
Wrong function is selected.
Defective volume control
Defective earphone jack
Defect in IC402
Defect in IC301
No soundGeneral
Remedy
Check the speaker connection.
Set switch to the proper position.
Set the volume control to a proper sound
level.
Replace the earphone jack.
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Improper location of unit
Defect in IF T101
Defect AM antenna coil L103 or oscilloscope
coil L102
Intermediate frequency tuning faulty
RF tracking faulty
Defective IC101
Defective IC102
Poor contact in antenna circuit
No sound, weak sound
(Low sensitivity)
MW Rotate or reposition the unit.
Check resistance, voltage, and current.
Replace as needed.
Replace if necessary.
Readjust (see "Adjustment method").
Readjust (see "Adjustment method").
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Check resistance and resolder.
FM antenna not connected
Defective band selector switch
Defective IC101
Defective IC102
Intermediate frequency tuning faulty
Poor contact in FM antenna circuit
No sound, weak sound
(Low sensitivity)
FM Connect the built-in or external antenna.
Replace or repair the switch.
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Readjust (see "Adjustment method").
Resolder or repair as required.
Dirty capstan or head
Irregular cassette tape winding
Defective IC201
Defective IC202
Cassette erasure prevention tabs broken out
No sound/recording,
unsteady tape sound,
weak sound
Tape Clean the capstan or head with alcohol.
Replace tape.
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Replace tape or cover tab openings with
adhesive tape.
Disc is inserted upside down.
Disc is dirty.
Disc is scratched.
Disc is seriously warped.
A non-standard disc has been inserted.
Moisture has formed inside the CD deck.
Defective IC701
Defective IC704
Defective IC703
Defect in the CD pickup mechanism
Cannot read the table
of content.
No sound
CD Insert disc correctly.
Wipe clean with a soft cloth.
Use a new disc.
Use a new disc.
Use only a brand name disc.
Wait about 20 to 30 minutes.
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Check voltages. Replace if necessary.
Replace as required.