JVC KD-AR470 - Radio / CD User manual

SERVICE MANUAL
COPYRIGHT © 2005 Victor Company of Japan, Limited No.MA232
2005/11
CD RECEIVER
MA232200511
KD-AR470,KD-G420,KD-G521,
KD-G524,KD-G525,KD-G527
Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)
TABLE OF CONTENTS
1 PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Area suffix
J ------------- Northern America
KD-AR470,KD-G420
Area suffix
E ------------- Southern Europe
EX ------------ Northern Europe
EY ------------- Eastern Europe
EU ------------------------- Turkey
KD-G521
Area suffix
UI ---------------------------- India
KD-G524
Area suffix
UT ------------------------- Taiwan
UH ---------------------- Thailand
UN --------------------- Indonesia
U -------------------- Other Areas
KD-G525
Area suffix
EE -------- Russian Federation
KD-G527
KD-AR470
KD-G527
KD-G420
KD-G521 KD-G524
KD-G525

1-2 (No.MA232)
SPECIFICATION
• Microsoft and Windows Media are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.
•Design and specifications are subject to change without notice.
AUDIO AMPLIFIER SECTION
Power Output KD-AR470, KD-G420 20 W RMS ×4 Channels at 4 Ωand [< or =] 1% THD+N
Maximum Power Output KD-G521, KD-G524,
KD-G525, KD-G527
Front 50 W per channel
Rear 50 W per channel
Continuous Power Output
(RMS)
KD-G521, KD-G524,
KD-G525, KD-G527
Front 19 W per channel into 4 Ω, 40 Hz to 20 000 Hz at no more than 0.8% total
harmonic distortion.
Rear 19 W per channel into 4 Ω, 40 Hz to 20 000 Hz at no more than 0.8% total
harmonic distortion.
Signal to Noise Ratio KD-AR470, KD-G420 80 dBA (reference: 1 W into 4 Ω)
KD-G521, KD-G524, KD-G525, KD-G527 70 dB
Load Impedance 4 Ω(4 Ωto 8 Ωallowance)
Tone Control Range Bass ±10 dB at 100 Hz
Treble ±10 dB at 10 kHz
Frequency Response 40 Hz to 20 000 Hz
Line-Out Level/Impedance KD-AR470 4.0 V/20 kΩload (full scale)
KD-G420, KD-G521, KD-G524,
KD-G525, KD-G527
2.5 V/20 kΩload (full scale)
Output Impedance 1 kΩ
Other Terminals CD changer, Steering wheel remote input ( Only KD-G521 ), AUX (auxiliary)
input jack
TUNER SECTION
Frequency Range FM ( KD-AR470, KD-G420 ) 87.5 MHz to 107.9 MHz (with channel interval set to 100 kHz or 200 kHz)
87.5 MHz to 108.0 MHz (with channel interval set to 50 kHz)
FM ( KD-G521, KD-G524, KD-G525 ) 87.5 MHz to 108.0 MHz
FM1/FM2 ( KD-G527 ) 87.5 MHz to 108.0 MHz
FM3 ( KD-G527 ) 65.00 MHz to 74.00 MHz
AM ( KD-AR470, KD-G420 ) 530 kHz to 1 710 kHz (with channel interval set to 10 kHz)
531 kHz to 1 602 kHz (with channel interval set to 9 kHz)
AM ( KD-G521, KD-G527 ) (MW) 522 kHz to 1 620 kHz
(LW) 144 kHz to 279 kHz
AM ( KD-G524, KD-G525 ) 531 kHz to 1 602 kHz
FM Tuner Usable Sensitivity 11.3 dBf (1.0 µV/75 Ω)
50 dB Quieting Sensitivity 16.3 dBf (1.8 µV/75 Ω)
Alternate Channel Selectivity (400 kHz) 65 dB
Frequency Response 40 Hz to 15 000 Hz
Stereo Separation 35 dB
Capture Ratio 1.5 dB
AM Tuner KD-AR470, KD-G420,
KD-G524, KD-G525
Sensitivity 20 µV
Selectivity 35 dB
MW Tuner KD-G521, KD-G527 Sensitivity 20 µV
Selectivity 35 dB
LW Tuner KD-G521, KD-G527 Sensitivity 50 µV
CD PLAYER SECTION
Type Compact disc player
Signal Detection System Non-contact optical pickup (semiconductor laser)
Number of Channels 2 channels (stereo)
Frequency Response 5 Hz to 20 000 Hz
Dynamic Range 96 dB
Signal-to-Noise Ratio 98 dB
Wow and Flutter Less than measurable limit
MP3 Decoding Format MPEG1/2 Audio Layer 3
Max. Bit Rate: 320 kbps
WMA (Windows Media® Audio) Decoding Format Max. Bit Rate: 192 kbps
GENERAL
Power Requirement Operating Voltage DC 14.4 V (11 V to 16 V allowance)
Grounding System Negative ground
Allowable Operating Temperature 0°C to +40°C (32°F to 104°F)
Dimensions (W ×H ×D) Installation Size (approx.) 182 mm ×52 mm ×150 mm (7-3/16" ×2-1/16" ×5-15/16")
Panel Size (approx.) 188 mm ×58 mm ×11 mm (7-7/16" ×2-5/16" ×7/16")
Mass (approx.) 1.5 kg (3.3 lbs) (excluding accessories)

(No.MA232)1-3
SECTION 1
PRECAUTIONS
1.1 Safety Precautions
!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.
!Please use enough caution not to see the beam directly or touch it in case of an
adjustment or operation check.

1-4 (No.MA232)
1.2 Preventing 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.
1.2.1 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.
(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) Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
(3) Handling the optical pickup
• 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.
1.3 Handling the traverse unit (optical pickup)
(1) Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.
(2) Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific details, refer to the
replacement procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a
time when attaching it to the connector.
(3) Handle the flexible cable carefully as it may break when subjected to strong force.
(4) It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
1.4 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 flexible wire is disconnected from the connector on the CD pickup unit.
(If the flexible 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 flexible wire.
1M
(caption)
Anti-static wrist strap
Conductive material
(conductive sheet) or iron plate
Pickup
Short-circuit point
(Soldering)
Flexible wire
Pickup
Short-circuit point

(No.MA232)1-5
1.5 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 CD,MD and DVD player uses invisible
laser radiation and is equipped with safety switches which
prevent emission of radiation when the drawer is open and
the safety interlocks have failed or are defeated. It is
dangerous to defeat the safety switches.
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 here in may result in
hazardous radiation exposure.
REPRODUCTION AND POSITION OF LABELS
!
Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
WARNING LABEL
CAUTION : Visible and Invisible
laser radiation when open and
interlock failed or defeated.
AVOID DIRECT EXPOSURE TO
BEAM. (e)
VARNING : Synlig och
osynling laserstrålning när
den öppnas och spärren är
urkopplad. Betrakta ej
strålen. (s)
VARO : Avattaessa ja suojalukitus
ohitettuna tai viallisena olet alttiina
näkyvälle ja näkymättömälle
lasersäteilylle. Vältä säteen
kohdistumista suoraan itseesi. (f)
ADVARSEL : Synlig og usynlig
laserstråling når maskinen er
åben eller interlocken fejeler.
Undgå direkte eksponering til
stråling. (d)
CLASS 1
LASER PRODUCT

1-6 (No.MA232)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 Difference point
[KD-AR470, KD-G420, KD-G524 and KD-G525]
[KD-G521, KD-G527]
2.2 CD mechanism
For Cd mechanism, please refer mechanism amnual No. MY001.
KD-AR470 KD-G420/KD-G524/KD-G525
Remote controller YES NO
Telephone Muting YES NO
Line Out Level / Impedance 4.0V / 20kohm load 2.5V / 20kohm load
KD-G521 KD-G527
Steering wheel remote input YES NO

(No.MA232)1-7
SECTION 3
DISASSEMBLY
3.1 Main body section
3.1.1 Removing the front panel assembly
(See Fig.1)
(1) Push the control panel release button in the lower left part
of the front panel assembly and remove the front panel as-
sembly.
(2) Take out the front panel assembly.
Fig.1
3.1.2 Removing the bottom cover
(See Fig.2)
(1) Turn the main body up side down.
(2) Insert a screwdriver under the joints to release the joints a
on the left side, joints bon the right side and joint con the
back side of the main body, then remove the bottom cover
from the main body.
Caution:
When releasing the joints using a screwdriver, do not damage
the main board.
Fig.2
Front panel assembly
Control panel release button
Bottom cover
a
b
a
b
c

1-8 (No.MA232)
3.1.3 Removing the front chassis assembly
(See Figs.3 and 4)
• Remove the front panel assembly and bottom cover.
(1) Remove the two screws Aon the front side of the main
body. (See Fig.3)
(2) Remove the two screws Bon the both sides of the main
body. (See Fig.4)
(3) Release the joints dand joints eon the both sides of the
main body, then remove the front chassis assembly toward
the front. (See Fig.4)
Fig.3
Fig.4
3.1.4 Removing the side panel
(See Fig.5)
Reference:
Remove the front panel assembly as required.
(1) Remove the two screws Cand screw Dattaching the side
panel on the left side of the main body.
(2) Take out the side panel from the main body.
Fig.5
A
Front chassis assembly
d
d
Front chassis assembly
B
e
e
B
Side panel
CCD

(No.MA232)1-9
3.1.5 Removing the rear bracket
(See Fig.6)
[For KD-AR470, KD-G420, KD-G524 and KD-G525]
• Remove the bottom cover.
(1) Remove the three screws E, three screws Fand three
screws Gattaching the rear bracket on the back side of the
main body.
(2) Take out the rear bracket.
3.1.6 Removing the rear bracket
(See Fig.6)
[For KD-G521 and KD-G527]
• Remove the bottom cover.
(1) Remove the three screws E, three screws Fand screw G
attaching the rear bracket on the back side of the main
body.
(2) Remove the screw Hattaching the steering remote cable
on the rear bracket. [KD-G521 only]
(3) Take out the rear bracket.
3.1.7 Removing the main board
(See Figs.6 and 7)
• Remove the front panel assembly, bottom cover, front chassis
assembly and side panel.
(1) Remove the three screws Eattaching the rear bracket on
the back side of the main body. (See Fig.6.)
(2) Remove the two screws Jattaching the main board. (See
Fig.7.)
(3) Disconnect the connector CN101 and take out the main
board. (See Fig.7.)
Reference:
Remove the rear bracket as required.
Fig.6
Fig.7
F
E E
Rear bracket
GFG
[For KD-AR470, KD-G420, KD-G524 and KD-G525]
E
F
Rear bracket
E
E
FG
H
Steering remote cable [KD-G521 only]
[For KD-G521 and KD-G527]
Main board
J
J
CN101
Rear bracket
[For KD-AR470, KD-G420, KD-G524 and KD-G525]
[For KD-G521 and KD-G527]
Main board
J
J
CN501
Rear bracket

1-10 (No.MA232)
3.1.8 Removing the CD mechanism control board
(See Fig.8)
[For KD-AR470, KD-G420, KD-G524 and KD-G525]
• Remove the front panel assembly, bottom cover, front chassis
assembly, side panel and main board.
(1) Disconnect the card wire from the connector CN601 on the
CD mechanism control board.
(2) Remove the five screws Kattaching the CD mechanism
control board.
(3) Remove the joint fan upward direction and remove the
joint gin the direction of the arrow.
Fig.8
3.1.9 Removing the CD mechanism assembly
(See Fig.9)
• Remove the front panel assembly, bottom cover, front chassis
assembly, side panel, main board and CD mechanism control
board.
(1) Remove the three screws Mattaching the top chassis.
(2) Take out the CD mechanism assembly.
Fig.9
CD mechanism control board
CN601
K
K
K
f
g
M
M
CD mechanism assembly Top chassis

(No.MA232)1-11
3.1.10 Removing the switch board
(See Figs.10 to 12)
• Remove the front panel assembly.
(1) Remove the five screws Nattaching the front panel assem-
bly. (See Fig.10)
(2) Release the ten joints hand take out the rear cover. (See
Fig.11)
(3) Lift the switch board from the front panel assembly little by
little and take out the switch board. (See Fig.12)
Reference:
The volume knob is removed from the front side simultaneous-
ly.
Note:
When removing the rear cover assembly and switch board, be
careful not to lose the compression spring and comp. spring.
(See Fig.12)
Fig.10
Fig.11
Fig.12
N
Rear cover
Rear cover
hh
hh
Switch board
Compression spring
Comp. spring
Front panel assembly

1-12 (No.MA232)
SECTION 4
ADJUSTMENT
4.1 Adjustment method
Test instruments required for adjustment
(1) Digital oscilloscope (100MHz)
(2) Electric voltmeter
(3) Digital tester
(4) Tracking offset meter
(5) Test Disc JVC :CTS-1000
(6) Extension cable for check
EXTSH002-22P ×1
Standard volume position
Balance and Bass &Treble volume : lndication"0"
Loudness : OFF
Standard measuring conditions
Dummy load
Exclusive dummy load should be used for AM,and FM. For FM
dummy load,there is a loss of 6dB between SSG output and
antenna input.The loss of 6dB need not be considered since
direct reading of figures are applied in this working standard.
How to connect the extension cable for adjusting
[For KD-AR470, KD-G420, KD-G524 and KD-G525]
Caution:
Be sure to attach the heat sink and rear bracket onto the power amplifier IC and regulator IC respectively, before supply the power.
If voltage is applied without attaching these parts, the power amplifier IC and regulator IC will be destroyed by heat.
Power supply voltage DC14.4V(11 to 16V)
Load impedance 20KΩ(2 Speakers connection)
Output Level
KD-ARxxx Line out 4.0V (Vol. MAX)
KD-Gxxx Line out 2.5V (Vol. MAX)
Side panel Rear bracket
CN101
Extension cable: EXTSH002-22P

(No.MA232)1-13
How to connect the extension cable for adjusting
[For KD-G521 and KD-G527]
Caution:
Be sure to attach the heat sink and rear bracket onto the power amplifier IC and regulator IC respectively, before supply the power.
If voltage is applied without attaching these parts, the power amplifier IC and regulator IC will be destroyed by heat.
Side panel
EXTSH002-22P
Extension cable
Rear bracket
CN501

1-14 (No.MA232)
SECTION 5
TROUBLESHOOTING
5.1 Trouble shooting (For KD-AR470, KD-G420, KD-G524 and KD-G525)
5.1.1 Feed section
5.1.2 Focus section
Check the feed motor.
Is 4V present at both
sides of the feed motor?
YES
NO
Is the voltage output at
pin 17 and pin 18 of IC681?
Is the power supply
present at pin 10, pin 19
and pin 28 of IC681?
Check the connections
between the feed motor
and IC681.
YES
NO
Is the voltage input at pin
24 of IC681?
YES YES Check IC681.
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at pin
40 of IC621?
Check the connections
between IC621 and
IC681.
YES
NO
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC621?
YES Check IC621.
NO
Check the connections
of CD8V power supply.
When the lens is
moving:
Does the S-search
waveform appear at
IC681 pins 13 and 14?
4V
Check the pickup and
its connections.
YES
NO
Is the voltage input at pin
1 of IC681?
YES
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at
pin 33 of IC621?
NO
YES
Check the connections
between IC621 and
IC681.
YES Check IC621.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 10, pin 19
and pin 28 of IC681?
YES Check IC681.
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC621?

(No.MA232)1-15
5.1.3 Spindle section
5.1.4 Tracking section
Is the disk rotated?
NO
YES
Is the voltage output at
pin 15 and pin 15 of IC681?
Does the RF signal appear
at RF output of IC601?
YES
Check the spindle motor
and its wiring.
Is the RF waveform
at TP RF distorted?
Proceed to the Tracking
section
Check the circuits in
the vicinity of IC601
or the pickup.
YES
NONO
YES
NO
Is the voltage input at pin
26 of IC681?
YES
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at pin
41 of IC621?
Check the connections
between IC621 and
IC681.
YES
NO
YES Check IC621.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 10, pin 19
and pin 28 of IC681?
YES Check IC681.
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC621?
When the disc is rotated
at first:
Approx. 1.2V
Is the tracking error
signal output at pin 11
of IC601?
Check the circuits in
IC601 or the vicinity
of IC601.
Replace IC601 or repair
the malfunction
connection point
YES Check IC621.
NO
Check the pickup and
its connections.
YES
NO

1-16 (No.MA232)
5.1.5 Signal processing section
No sound from either
channel.
Is 9V present at pin 36
of IC161?
Compare the L-ch and
R-ch to locate the
defective point.
Is the sound output from
both channels (L, R)?
YES
NO Is the audio signal
(including sampling
output components)
output to pins 1 and 7 of
IC572 during playback?
Is the audio signal output
at pin 19 and pin 20 of
IC161 during playback?
Normal
YES
NO
YES YES
NO
Check IC572 and its
peripheral circuits.
NO
Check IC161 and its
peripheral circuits.
YES
Check the power
amplifier IC301.
NO
Is 9V present at pin 10
of IC901?
YES
Check the connections
between pin 36 of IC161
and pin 10 of IC901.
NO
Check IC901 and its
peripheral circuits.

(No.MA232)1-17
5.2 Trouble shooting (For KD-G521 and KD-G527)
5.2.1 Feed section
5.2.2 Focus section
Check the feed motor.
Is 4V present at both
sides of the feed motor?
YES
NO
Is the voltage output at
pin 4 and pin 5 of IC501?
Is the power supply
present at pin 3, pin 12
and pin 21 of IC501?
Check the connections
between the feed motor
and IC501.
YES
NO
Is the voltage input at pin
27 of IC501?
YES YES Check IC501.
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at pin
40 of IC541?
Check the connections
between IC501 and
IC541.
YES
NO
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC541?
YES Check IC541.
NO
Check the connections
of CD8V power supply.
When the lens is
moving:
Does the S-search
waveform appear at
IC501 pins 8 and 9?
4V
Check the pickup and
its connections.
YES
NO
Is the voltage input at pin
15 of IC501?
YES
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at
pin 33 of IC541?
NO
YES
Check the connections
between IC501 and
IC541.
YES Check IC541.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC541?
Is the power supply
present at pin 3, pin 12
and pin 21 of IC501?
YES Check IC501.

1-18 (No.MA232)
5.2.3 Spindle section
5.2.4 Tracking section
Is the disk rotated?
NO
YES
Is the voltage output at
pin 6 and pin 7 of IC501?
Does the RF signal
appear at TP RF?
YES
Check the spindle motor
and its wiring.
Is the RF waveform
at TP RF distorted?
Proceed to the Tracking
section
Check the circuits in
the vicinity of IC601
or the pickup.
YES
NONO
YES
NO
Is the voltage input at pin
17 of IC501?
YES
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at pin
41 of IC541?
Check the connections
between IC501 and
IC541.
YES
NO
YES Check IC541.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 6, pin 15,
pin 25, pin 39, pin 43,
pin 51 and pin 64 of IC541?
Is the power supply
present at pin 3, pin 12
and pin 21 of IC501?
YES Check IC501.
When the disc is rotated
at first:
Approx. 1.2V
Is the tracking error
signal output at pin 11
of IC521?
Check the circuits in
IC521 or the vicinity
of IC521.
Replace IC521 or repair
the malfunction
connection point
YES Check IC521.
NO
Check the pickup and
its connections.
YES
NO

(No.MA232)1-19
5.2.5 Signal processing section
No sound from either
channel.
Is 9V present at pin 26
of IC161?
Compare the L-ch and
R-ch to locate the
defective point.
Is the sound output from
both channels (L, R)?
YES
NO Is the audio signal
(including sampling
output components)
output to pins 1 and 7 of
IC581 during playback?
Is the audio signal output
at pin 19 and pin 20 of
IC161 during playback?
Normal
YES
NO
YES YES
NO
Check IC581 and its
peripheral circuits.
NO
Check IC161 and its
peripheral circuits.
YES
Check the power
amplifier IC301.
NO
Is 9V present at pin 10
of IC901?
YES
Check the connections
between pin 26 of IC161
and pin 10 of IC901.
NO
Check IC901 and its
peripheral circuits.

1-20 (No.MA232)
5.3 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: amplitude of eye
pattern) will be low.
(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 la-
ser diode is almost worn out, and the laser pickup should
be replaced. If the semi-fixed resistor is adjusted while the
pickup is functioning normally, the laser pickup may be
damaged due to excessive current.
5.4 Replacement of laser pickup
Is RF output
1.3 0.4Vp-p?
YES
NO
OK
Replace it.
Turn of the power switch and, disconnect the
power cord.
Replace the pickup with a normal one. (Refer
to "Removing the pickup unit" on the previous page.)
Plug the power cord in, and turn the power on.
At this time, check that the laser emits for about
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
RF output or TP RF.
Finish.
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