JVC XV-521BK User manual

SERVICE MANUAL
No.20836
XV-521BK/523GD
XV-525BK/421BK
XV-521BK/523GD
XV-525BK/421BK
Contents
Safety precautions
Importance administering
point on the safety
Dismantling and assembling
the traverse unit
Instructions
Disassembly method
Main adjustment
Check points for each error
Precautions for service
Description of major ICs
Block diagram
Standard schematic diagrams
Printed circuit boards
Parts list
1-2
1-3
1-4
1-5
1-15
1-18
1-23
1-24
2-1
2-5
2-12
3-1~
VICTOR COMPANY OF JAPAN, LIMITED
AUDIO & COMMUNICATION BUSINSS DIVISION
PERSONAL & MOBILE NETWORK B.U. 10-1,1Chome,Ohwatari-machi,Maebashi-city,371-8543,Japan
DVD PLAYER
No.20836
Jun. 2000
COPYRIGHT 2000 VICTOR COMPANY OF JAPAN, LTD.
Printed in Japan
2000 06 (S)
XV-521BK/523GD
XV-525BK/421BK
J U.S.A
Area Suffix
XV-525BK/523GD
J
C
U.S.A
Canada
C Canada
Area Suffix
XV-521BK
Area Suffix
XV-421BK

XV-521BK/523GD/525BK/421BK
1-2
Safety Precautions
1. This design of this product contains special hardware and many circuits and components specially
for safety purposes. For continued protection, no changes should be made to the original design
unless authorized in writing by the manufacturer. Replacement parts must be identical to those
used in the original circuits. Services should be performed by qualified personnel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of
the product should not be made. Any design alterations or additions will void the manufacturer`s
warranty and will further relieve the manufacture of responsibility for personal injury or property
damage resulting therefrom.
3. Many electrical and mechanical parts in the products have special safety-related characteristics.
These characteristics are often not evident from visual inspection nor can the protection afforded
by them necessarily be obtained by using replacement components rated for higher voltage,
wattage, etc. Replacement parts which have these special safety characteristics are identified in
the Parts List of Service Manual. Electrical components having such features are identified by
shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a
substitute replacement which does not have the same safety characteristics as the recommended
replacement parts shown in the Parts List of Service Manual may create shock, fire, or other
hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the
like to be separated from live parts, high temperature parts, moving parts and/or sharp edges
for the prevention of electric shock and fire hazard. When service is required, the original lead
routing and dress should be observed, and it should be confirmed that they have been returned
to normal, after re-assembling.
5. Leakage currnet check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal parts
of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control
shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.
Do not use a line isolation transformer during this check.
Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure
the leakage current from each exposed metal parts of the cabinet , particularly any exposed
metal part having a return path to the chassis, to a known good earth ground. Any leakage
current must not exceed 0.5mA AC (r.m.s.)
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms
per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by
a 0.15 F AC-type capacitor between an exposed
metal part and a known good earth ground.
Measure the AC voltage across the resistor with the
AC voltmeter.
Move the resistor connection to eachexposed metal
part, particularly any exposed metal part having a
return path to the chassis, and meausre the AC
voltage across the resistor. Now, reverse the plug in
the AC outlet and repeat each measurement. voltage
measured Any must not exceed 0.75 V AC (r.m.s.).
This corresponds to 0.5 mA AC (r.m.s.).
Warning
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
!
CAUTION
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.

XV-521BK/523GD/525BK/421BK
1-3
Caution: For continued protection against risk of
fire, replace only with same type 2A/250V for
F8901, 1.6A/250V for F8911 and F8921. This symbol
specifies type of fast operating fuse.
Precaution: Pour eviter risques de feux, remplacez
le fusible de surete de F8901 comme le meme type
que 2A/250V, et 1.6A/250V pour F8911 et F8921.
Ce sont des fusibles suretes qui functionnes rapide.
^
Importance administering point on the safety
For USA and Canada / pour Etats - Unis d' Amerique et Canada

XV-521BK/523GD/525BK/421BK
1-4
Dismantling and assembling the traverse unit
1. Notice regarding replacement of optical pickup
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 to the optical pickup or connected devices.
(Refer to the section regarding anti-static measures.)
1. Do not touch the area around the laser diode and actuator.
2. Do not check the laser diode using a tester, as the diode may easily be destroyed.
3. It is recommended that you use a grounded soldering iron when shorting or removing the laser diode.
Recommended soldering iron: HAKKO ESD-compatible product
4. Solder the land on the optical pickup's flexible cable.
Note : Short the land after shorting the terminal on the flexible cable using a clip, etc., when using an
ungrounded soldering iron.
Note : After shorting the laser diode according to the procedure above, remove the solder according
to the text explanation.
Short circuit land
Laser pick-up unit
Flexible cable
Shot with the rclip
Shorting

XV-521BK/523GD/525BK/421BK
1-5
Remove the four screws A on both side of the body.
Remove the two screws B on the back of the body.
Lift up the rear part of the top cover while pulling the
lower part of the sides, then detach upward.
1.
2.
3.
Disassembly method
< Main body>
Removing the top cover (See Fig.1)
Prior to performing the following procedure, remove
the top cover.
Remove the seven screws C on the back of the
body.
1.
Removing the rear panel (See Fig.2)
Fig.1
Fig.2
Top cover
Rear panel
B
C
C
A
2
A 2
C
C

XV-521BK/523GD/525BK/421BK
1-6
Prior to performing the following procedure, remove
the top cover.
by hand
Turn over the body. Insert a screwdriver into the hole
of the bottom chassis and turnit. The loading tray will
be ejected out of the front panel assembly.
Pull the loading tray toward the front.
Remove the fitting upward from the loading tray at
the joints b.
Push and return the loading tray.
1.
2.
3.
4.
Removing the fitting (See Fig.3 to 6)
To remove the front panel assembly
and the DVD mechanism assembly,
remove the fitting in advance.
ATTENTION:
Front panel
Front panel assembly
Loading tray
Hole
Bottom chassis
(Bottom)
Fig.3
Fig.4
Fig.5
Fig.6
Front panel assembly
Fitting
Joint b
Joint b
Loading tray
Loading tray
Front panel assembly
DVD mechanism assembly
TRAY OPEN

XV-521BK/523GD/525BK/421BK
1-7
Prior to performing the following procedure, remove
the top cover and the fitting.
Disconnect the card wire from connector CN703 on
the main board.
Turn over the body and remove the screw D
attaching the front panel assembly.
Release the five joints c on both sides and bottom of
the body and remove the front panel assembly
toward the front.
1.
2.
3.
Removing the front panel assembly
(See Fig.7 to 10)
The connector CN832 on the front
panel assembly and CN971 on the AC
jack board will be disconnected at the
same time.
ATTENTION: Fig.7
Fig.8
Fig.9
Fig.10
Main board
D
DC mechanism assembly
AC jack board
Front panel assembly
CN703
CN971
Joint c Joint c
Front panel assembly
Joint c
Front panel assembly
Joint c

XV-521BK/523GD/525BK/421BK
1-8
Prior to performing the following procedure, remove
the top cover and the front panel assembly.
Disconnect the card wire from connector CN101 on
the DVD Servo.
Disconnect the harness from connector CN031 on
the DVD mechanism assembly.
Remove the screw E on the rear left part of the
loading tray.
From the front side of the DVD mechanism
assembly, move the lever d in the direction of the
arrow and pull out the loading tray.
Remove the two screws F on the upper side of the
DVD mechanism assembly. Then release the two
joints e and detach the clamper base back-upward.
Remove the three screws G attaching the DVD
mechanism assembly.
1.
2.
3.
3.
4.
5.
Removing the DVD mechanism assembly
(See Fig.11 to 14)
Fig.11
Fig.12
Fig.13
Fig.14
Loading tray
Loading tray
CN101
CN101
Joint e Joint eClamper base
P031
Lever d
DVD Servo
DVD mechanism assembly
P031
DVD mechanism assembly
DVD mechanism assembly
E
F
G
GG
F
CN101
DVD mechanism assembly

XV-521BK/523GD/525BK/421BK
1-9
Prior to performing the following procedure, remove
the top cover and the front panel assembly.
Remove the two screws H attaching the AC jack
board.
Remove the two screws C on the rear panel.
Disconnect connector CN951 and CN961 on the AC
jack board from CN704 and CN705 on the main
board respectively.
1.
2.
3.
Removing the AC jack board
(See Fig.15 and 16)
Prior to performing the following procedure, remove
the top cover.
Remove the screw I attaching the DVD Servo.
Pull out the DVD Servo from the fix f while pinching
the fix f.
Disconnect connector CN501, CN502 and CN503 on
the DVD Servo from CN601, CN701 and CN706 on
the main board respectively.
1.
2.
3.
Removing the DVD Servo
(See Fig.17 and 18)
Fig.15
Fig.16
Fig.17
Fig.18
C
I
H
H
CN951 / CN705
CN961 / CN704
Rear panel
CN501 / CN706
DVD Servo
DVD Servo
Main board
CN503 / CN701CN502 / CN701
CN101
Fix f
Fix f
Main boardAC jack board

XV-521BK/523GD/525BK/421BK
1-10
Prior to performing the following procedure, remove
the top cover, the front panel assembly, the DVD
mechanism assembly, the AC jack board and the
DVD Servo .
Remove the three screws J attaching the main
board.
Remove the two screws C on the rear panel.
1.
2.
Removing the main board
(See Fig.19 and 20)
Unsolder connector FW841 on the power switch
board on the back of the front panel assembly.
Remove the two screws K attaching the power
switch board.
Push the two tabs g in the direction of the arrow and
remove the power switch board.
1.
2.
3.
Removing the power switch board
(See Fig.21)
Unsolder soldering i on the search switch board.
Remove the three screws M.
Release the four tabs j in the direction of the arrow
and remove the search switch board.
1.
2.
3.
Removing the search switch board
(See Fig.20)
Unsolder connector FW802 and soldering h on the
LCD board.
Remove the four screws L attaching the LCD board.
1.
2.
Removing the LCD board (See Fig.22)
Prior to performing the following procedure, remove
the top cover and the front panel assembly.
<Front panel assembly>
Fig.19
Fig.20
Fig.21
Fig.22
J
Main board
J
C
K
K
L
M
M
LLL
J
Rear panel
Power switch board
Front panel assembly
FW841
FW802
hi
Tabs j 4
Tabs g
Front panel assemblySearch switch board
LCD board

XV-521BK/523GD/525BK/421BK
1-11
Remove the screw A and the spring on the upper
side of the loading base assembly.
Move the rear part of the traverse mechanism unit
upward and pull backward to release the two joints a
with the base chassis.
1.
2.
Disassembly method
<DVD mechanism>
Removing the traverse mechanism unit
(See Fig.1 and 2)
Move the cam plate on the upper side of the loading
base assembly in the direction of the arrow.
Remove the belt from the motor pulley.
Remove the two screws B attaching the loading
motor.
Turn over the loading base assembly and release the
loading motor board from the three tabs b while
spreading them outward. The loading motor board
will be detached with the loading motor.
Unsolder soldering c on the loading motor board and
remove the loading motor.
1.
2.
3.
4.
5.
Removing the loading motor / loading
motor board (See Fig.3 and 4)
When reattaching, engage the two
joints a and make sure the front
springs and the four insulators of the
traverse mechanism unit are correctly
attached.
ATTENTION:
To remove the loading motor board only,
unsolder soldering c on the loading motor and
release the three tabs b.
Ref.:
Fig.1
Fig.2
Fig.3
Fig.4
A
A
B
B
Traverse mechanism unit
Spring
Spring
Loading motor board
Loading motor
Belt
Cam plate
c
Tab b
Tab b
Tab b
Joints a
Joints a
Spring and Insulator
Spring and Insulator
Insulator

XV-521BK/523GD/525BK/421BK
1-12
It is not necessary to remove the traverse
mechanism unit.
Solder soldering d on the flexible board next to the
pickup unit.
From the bottom of the traverse mechanism unit,
disconnect the flexible wire from CN10 on the pickup
board.
1.
2.
Remove the screw C attaching the shaft stopper (R)
on the upper side of the traverse mechanism unit.
Pull the side of the shaft stopper (R) outward to
release the joint e and remove it upward. Remove
the skew spring at the same time.
Move the shaft in the direction of the arrow to release
it from the part f.
Release the joint g with the shaft and remove the
pickup with the shaft.
Pull out the shaft.
Remove the screw D attaching the switch actuator.
3.
4.
5.
6.
7.
Removing the pickup (See Fig.5 to 9)
Disconnecting the flexible wire without
soldering may cause damage to the
pickup.
ATTENTION: Fig.5
Fig.6
Fig.7
Fig.8Fig.9
Pickup unit
Flexible board
Flexible wire
Pickup unit
Shaft stopper (R)
Shaft stopper (R)
Shaft stopper (R)
Skew spring
Shaft
Shaft
Shaft
Pickup
Switch actuator
Shaft
Joint g
Joint e
Part f
Pickup board
CN10
d
C
C
D

XV-521BK/523GD/525BK/421BK
1-13
It is not necessary to remove the traverse
mechanism unit.
Solder soldering d on the flexible board next to the
pickup unit.
From the bottom of the traverse mechanism unit,
disconnect the flexible wire from CN10 on the pickup
board.
1.
2.
Unsolder soldering h, i and j of each harness on the
pickup board.
Remove the screw E attaching the pickup board and
release the two joints k.
3.
4.
Removing the pickup board
(See Fig.5 and 10)
Disconnecting the flexible wire without
soldering may cause damage to the
pickup.
ATTENTION:
Prior to performing the following procedure, remove
the traverse mechanism unit.
Solder soldering d on the flexible board next to the
pickup unit.
From the bottom of the traverse mechanism unit,
disconnect the flexible wire from CN10 on the pickup
board.
1.
2.
Unsolder soldering h of the motor harness on the
pickup board.
Remove the two screws F attaching the feed motor
assembly and remove the thrust spring. Move the
feed motor assembly in the direction of the arrow to
pull it out from the feed holder.
3.
4.
Removing the feed motor assembly
(See Fig.5, 10 and 11)
Disconnecting the flexible wire without
soldering may cause damage to the
pickup.
ATTENTION:
Fig.10
Fig.11
Pickup board
Feed motor assembly
Feed motor assembly
Thrust spring
Feed holder assembly
CN10
i
j
h
Joint k
Joint k
E
F
Fig.5
Pickup unit
Flexible board
d
F

XV-521BK/523GD/525BK/421BK
1-14
Prior to performing the following procedure, remove
the traverse mechanism unit.
Solder soldering d on the flexible board next to the
pickup unit.
From the bottom of the traverse mechanism unit,
disconnect the flexible wire from CN10 on the pickup
board.
1.
2.
Unsolder soldering i and j of the harness extending
from the turning table assembly to the pickup board.
Remove the screw G attaching the shaft stopper (F)
on the upper side of the traverse mechanism unit.
Pull the side of the shaft stopper (F) outward to
release the joint l and remove it upward. Remove the
spring at the same time.
Remove the screw H attaching the turn table
assembly.
Move the turn table assembly outward and pull out
from the shaft. Then remove it from the base chassis.
3.
4.
5.
6.
Removing the turn table assembly
(See Fig.5, 10, 12 and 13)
Disconnecting the flexible wire without
soldering may cause damage to the
pickup.
ATTENTION:
Fig.12
Fig.13
Fig.10
Pickup board
Feed motor assembly
Turn table assembly
Turn table assembly
Shaft stopper (F)
Shaft stopper (F)
Shaft
Shaft
Joint l
Shaft stopper (F)
CN10
i
j
h
Joint k
Joint k
E
G
H
H
G
G
Fig.5
Pickup unit
Flexible board
d

XV-521BK/523GD/525BK/421BK
1-15
(1) Auto adjustment method
(2) Confirmation of DVD RF level
(3) Confirmation of CD jitter level and RF level
If microprocessor (IC401, IC402, IC714, IC716) or pick up is replaced, initialize
the DVD player in the following matter:
1. Initialize the DVD player in the following matter:
1) Make sure that no disc is on the tray.
2) Insert the power pulag to the outret while pressing "PLAY" and "OPEN/CLOSE" button at the
same time.
FL Display indicate "TEST ; Version.
3) Press Enter button. And EEPROM initialize start.
4) When indicate "96kHz EEPROM" on the display , initialize finished.
Note : During the EEPROM initialization the keys may not be operated.
Press the "POWER" key to initiate the STAND-BY mode and the test mode will then
be cancelled.
Adjustment and confirmation matter
1.The oscilloscope is connected between "1"(RFOP) of
CN104 and "2"(GND).
2.Reproduction of the test disc ( VT-502)
made by JVC.
3.It is confirmed that RF LEVEL is 350mVp-p 150mVp-p.
4.When there is disorder in the waveform road cuts etc,
test disk is exchanged and measured.
1. The CD jitter meter is connected between "11"(GND)
of CN104 and "12"(FLTOUT).
The RF level is observed at the same time.
2. The first test disk(CTS-1000) made of JVC is reproduced.
3. It is confirmed that RF LEVEL is 360 100mVp-p.
5. When there is disorder in the waveform road cuts
etc, test disk is exchanged and measured.
FRONT SIDE
12 ~ 1
RFOP
GNDGNDFLTOUT "1""2""11""12"
CN104
Main adjustment
DVD SERVO CONTROL PWB

XV-521BK/523GD/525BK/421BK
1-16
Measurement
FL Display
Adjustment point
Refer to Fig.2
Mode
Reproduction
part
Disc
Measurement machine
No need
"Flap adjustment" of the Pick-up guide shaft adjusts
"Tangential adjustment machine screw" A and
"Tilt adjustment machine screw" B from the
DVD Mechanism A'ssy bottom.
1. The part at the center on the DVD test disc is
reproduced.
2.The flap adjustment screws is turned alternately
and adjusted like clearly seeing the waveform of
CN104"1" to the way.
Note
1.The tangential adjustment is done finish and,
then, tilt is adjusted.
2.The repeat the adjustment 2-3 times,for best
result.
3.The final adjustment should be tilt adjustment.
VT-501
DVD Mechanism A'ssy
Stand Stand
200mm
DVD player
Fig.1
CN101 of DVD Servo Control PWB
CN11 of
Connection PWB
Extension Cord
connections
Refer to Fig.1
Extension cord No.
QUQ605-4040AJ
General tool : Hex-head wrench(2mm)
(4)Flap adjustment of the Pick-up guide shaft
1) Make sure that there is no disc on the tray.
2) Press both the "PLAY" and "OPEN/CLOSE" keys of the main unit to activate the primary
power and "TEST 2 D2" will be displayed on the FL indicator.
Note: If the FL indicator display stops and remains at "TEST 0", unplug the power
cord from the outlet and after waiting at least 1 second, plug it in again. After
the tray open/close procedure has completed, unplug it again and then
perform the initialization procedure again.
3) Press the "OPEN/CLOSE" key of the main unit to draw the tray out.
*Place the test disk (VT-501) on the tray and then press the "OPEN/CLOSE" key.
(Note: Pushing the tray to close it is not possible.)
4) Press the "PLAY" key of the main unit.
5) The "JIT 0000" is displayed on the FL indicator.
Set the FL indicator figure value to its minimum by adjusting the pickup guide shaft flap.
* The test mode is cancelled when the power is turned off.

XV-521BK/523GD/525BK/421BK
1-17
Confirmation after adjustment.
Confirm to reproduce video CD and CD after
the DVD test disc is adjusted and to find abnormality.
(5) About keeping the disc
As for the DVD test disc, plane accuracy is demanded.Please note the keeping place on the disc.
1. Please do not put the disc directly on the work desk etc. after uses .
2.To keep the planarity of the disc, politely handle ,and please put in a special case and keep
the disc vertically after uses .
Please keep keeping the disc in a cool place where direct sunshine and the air-conditioning
wind do not drive.
3.When the disc curves,an accurate adjustment cannot be done.
Please exchange for a new test disc and adjust optics.
4 Other discs might not be able to be reproduced when adjusting on a curved disc.
A
A
B
Fig.2
Point of adjustment
* Please execute the static electricity protection measures before starting the
adjustment.
* When the following parts are exchanged,optical adjustment "Adjust the flap of the disc motor"
is necessary.
1.The disc motor was exchanged.
2.The laser pick up was exchanged.
3.The traverse motor unit was exchanged.
Note
Additionally, please adjust the flap of the disc motor when the picture quality deterioration is
seen .The basic adjustment though, is unnecessary for part exchange in the traverse.
An optical adjustment in the laser pick up cannot be done.
Please adjust the flap of the disc motor after exchanging the laser pick up.
* When the traverse unit is exchanged, the adjustment is basically unnecessary.

XV-521BK/523GD/525BK/421BK
1-18
Check points for each error
(1) Spindle start error
*Defective spindle motor
Are there 10ohms resistance between each pin of CN101 "29~31"?
(The power supply is turned off and measured.)
*Hall element: Is sine wave output between CN101 "23" and "24", between "25" and "26",
and between "27" and "28" during rotation?
In either case, replace the mechanical unit.
*Defective spindle driver (IC251)
Is a driving wave output from CN101 "29~31" ?
Is IC251 "9" at "H" level (START)?
Servo IC --- Is control signal sent to the motor driver ?
IC201 "95" : Duty is 50% during stop, but varies during rotation (greatly varies at start).
--- If not sent, pattern or servo IC (IC201) is defective.
R259 : approx 2.5V during stop, but varies during rotation (greatly varies at start).
--- of not sent, pattern or servo IC (IC201) is defective.
Is FG input to servo IC ?
Observe FG wave from IC201 "89". --- If not output, pattern, IC251 or IC201 is defective.
During
rotation
(2) Disc Detection, Distinction error (no disc, no REFNV)
* Laser is defective.
* Front End Processor is defective (IC101).
* APC circuit is defective. --- Q101.
* Pattern is defective. --- Lines for CN101 "15" and "17".
Lines for between IC201 "2" and IC101 "2"(LDONA),
between IC201 "3" and IC101 "1" (LDONB).
* Servo IC is defective (IC201).
* Is signal sent to IC201(servo)"71" AS2 ?
* IC101 --- For signal from IC101 to IC301, is signal output from IC101 "88" (RFAS1) and
IC101 "69" REENV ?

XV-521BK/523GD/525BK/421BK
1-19
50msec
Approx.
500mV GND
2.5V
(3) Traverse movement NG
* For automatic adjustment, traverse movement occurs only when the position is changed to retry
judging the disc type after the 1st judgment resulted in an error. Therefore, traverse movement
rarely occurs because, in most cases, disc judgment at the current position (1st time judgment)
is executed successfully. (Of course, NG rarely occurs in this step.)
Note: 1st time judgment of disc type resulted in NG. --- The re-judgment of disc type may not be
successful. Therefore, after removing the cause of traverse movement, re-execute automatic
adjustment and confirm that no problem exists.
* Check point
a) During stop
Whether 50% duty pulse is output to R273
Whether between R274 and C271 is at approx. 2.5VDC
Offset voltage between CN101 "34" and "35" (scores mV if exists)
b) When tray is opened or closed
Check by oscilloscope whether a rectangular wave signal is output from CN101 "34" or "35".
If checking a) or b) resulted in NG, IC201 maybe defective.
(4) Focus ON NG
* Is FE output ? --- Pattern, IC101
* Is FCDRV signal sent ? (R286) --- Pattern, IC301
* Is driving voltage sent ?
CN101 "20", "21" --- If NG, pattern, driver, mechanical unit (with the power turned off, measure the
resistance between CN101 "20" and "21").
* Does CN101 "7"(SRF1) become "H" and is the focus drawing in done?
--- Mechanical unit (laser power too low), IC101(defective gain)
--- Moreover, It is thought that abnormality is found in the disk.
* Mechanical unit is defective.
(5) Tracking ON NG
* When the tracking loop cannot be drawn in, IC201 "39" (/TRON) does not become "L".
* Mechanical unit is defective.
Because the undermentioned adjustment value is abnormal, it is not possible to draw in normally.
* Periphery of driver (IC271)
Constant or IC it self is defective.
(When passing without becoming abnormal while adjusting the following.)
* Servo IC (IC201)
When improperly adjusted due to defective IC.
[Focus position rough adjustment]
[Phase difference cancellation rough adjustment]
[Tracking balance adjustment]

XV-521BK/523GD/525BK/421BK
1-20
(6) Spindle CLV NG
* When the spindle cannot be shifted to CLV Servo, does not become "H" between IC301 "69"
and IC201"37".
* IC201 Is signal output from CN103 "1" (RFOP)?
* IC201 Is signal output from CN103 "11" (DSLIP)?
* IC201 Is signal output from CN103 "6" to "9" (binary-coded clock and data)?
* IC201 Is "39" (/TRON) at "L" level ?
* IC301 "74" to "76" --- Is signal output to IC201 "24", "25", "28" (In case of only CD).
(Serial communication of rotation information)
* Spindle motor driver is defective.
Even when one of the three phases is defective, item (1) may be passed.
--- Check the second item in (1) above.
* C260 to C263 Defective soldering
If noise eliminating capacitors are not properly soldered, noise may ride on the waveform.
* Besides, the undermentioned cause is thought though specific of the cause is difficult because various
factors are thought.
Mechanism is defective.(jitter)
IC101, IC201.
* Besides, the undermentioned cause is thought though specific of the cause is difficult because various
factors are thought.
Mechanism is defective. (jitter)
IC201, IC301, IC401.
The disc is dirty or the wound has adhered.
(7) Address read NG
(8) Between layers jump NG (double-layer disc only)
* When the focus flight is generated when jumps between layers.
Because all adjustments for L1 layer must be successful, this error may rarely be due to a
circuit defect.
* Crosstalk might occur from tracking to focus system. (See (11) ) --- Replace the mechanical unit.
* Driver surroundings.
* Defect of constant and IC.
* For double-layer discs, after checking CLV on layer L1, jumps to layer L0 after mode changes to FG.
Then tracking is turned off, and adjustments are executed from the focus position coarse adjustment
in order.
* When the jump between layers is done on the single-layer disk, the disk distinction error is thought.
--- The laser power is low (RF level is confirmed by CN102 "1" (RFOP)).
--- AS1, AS2, REFNV Is the signal sent to between IC101 and IC201 ?