JVC KD-AR370J User manual

SERVICE MANUAL
COPYRIGHT © 2006 Victor Company of Japan, Limited No.MA245
2006/1
CD RECEIVER
MA24520061
KD-AR370J,KD-G320J,KD-G421E,KD-G421EX,
KD-G421EY,KD-G421EU,KD-G424UI,KD-G425U,
KD-G425UN,KD-G425UT,KD-G425UH,KD-G427EE
Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)
TABLE OF CONTENTS
1 PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15

1-2 (No.MA245)
SPECIFICATION
KD-AR370/KD-G320
AUDIO AMPLIFIER SECTION
Power Output 18 W RMS ×4 Channels at 4 Ωand [< or =] 1% THD+N
Signal to Noise Ratio 80 dBA (reference: 1 W into 4 Ω)
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 2.5 V /20 kΩload (full scale)
Output Impedance 1 kΩ
Subwoofer-Out Level/Impedance 2.0 V /20 kΩload (full scale)
Other Terminal CD changer
TUNER SECTION
Frequency Range FM 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)
AM 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)
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 Sensitivity 20 µV
Selectivity 35 dB
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.) 1.4 kg (3.1 lbs) (excluding accessories)

(No.MA245)1-3
KD-G421
AUDIO AMPLIFIER SECTION
Maximum Power Output Front 50 W per channel
Rear 50 W per channel
Continuous Power Output (RMS) 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.
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
Signal-to-Noise Ratio 70 dB
Line-Out Level/Impedance 2.5 V/20 kΩload (full scale)
Output Impedance 1 kΩ
Other Terminals CD changer, Steering wheel remote input
TUNER SECTION
Frequency Range FM 87.5 MHz to 108.0 MHz
AM (MW) 522 kHz to 1 620 kHz
(LW) 144 kHz to 279 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 30 dB
Capture Ratio 1.5 dB
MW Tuner Sensitivity 20 µV
Selectivity 35 dB
LW Tuner 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
Dimensions (W ×H ×D) Installation Size (approx.) 182 mm ×52 mm ×150 mm
Panel Size (approx.) 188 mm ×58 mm ×11 mm
Mass (approx.) 1.4 kg (excluding accessories)

1-4 (No.MA245)
KD-G424
AUDIO AMPLIFIER SECTION
Maximum Power Output Front 50 W per channel
Rear 50 W per channel
Continuous Power Output (RMS) 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.
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
Signal-to-Noise Ratio 70 dB
Line-Out Level/Impedance 2.5 V/20 kΩload (full scale)
Subwoofer-Out Level/Impedance 2.0 V/20 kΩload (full scale)
Output Impedance 1 kΩ
Other Terminal CD changer
TUNER SECTION
Frequency Range FM 87.5 MHz to 108.0 MHz
AM 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 30 dB
Capture Ratio 1.5 dB
AM Tuner Sensitivity 20 µV
Selectivity 35 dB
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
Dimensions (W ×H ×D) Installation Size (approx.) 182 mm ×52 mm ×150 mm
Panel Size (approx.) 188 mm ×58 mm ×11 mm
Mass (approx.) 1.4 kg (excluding accessories)

(No.MA245)1-5
KD-G425
AUDIO AMPLIFIER SECTION
Maximum Power Output Front 50 W per channel
Rear 50 W per channel
Continuous Power Output (RMS) 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.
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
Signal-to-Noise Ratio 70 dB
Line-Out Level/Impedance 2.5 V/20 kΩload (full scale)
Subwoofer-Out Level/Impedance 2.0 V/20 kΩload (full scale)
Output Impedance 1 kΩ
Other Terminal CD changer
TUNER SECTION
Frequency Range FM 87.5 MHz to 108.0 MHz
AM 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 30 dB
Capture Ratio 1.5 dB
AM Tuner Sensitivity 20 µV
Selectivity 35 dB
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
Dimensions (W ×H ×D) Installation Size (approx.) 182 mm ×52 mm ×150 mm
Panel Size (approx.) 188 mm ×58 mm ×11 mm
Mass (approx.) 1.4 kg (excluding accessories)

1-6 (No.MA245)
KD-G427
• Microsoft and Windows Media are either registered trademarks or trademarks of Microsoft Corporation in the United States and/
or other countries.
• iPod is a trademark of Apple Computer, Inc., registered in the U.S. and other countries.
• Design and specifications are subject to change without notice.
AUDIO AMPLIFIER SECTION
Maximum Power Output Front 50 W per channel
Rear 50 W per channel
Continuous Power Output (RMS) 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.
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
Signal-to-Noise Ratio 70 dB
Line-Out Level/Impedance 2.5 V/20 kΩload (full scale)
Output Impedance 1 kΩ
Other Terminal CD changer
TUNER SECTION
Frequency Range FM1/FM2 87.5 MHz to 108.0 MHz
FM3 65.00 MHz to 74.00 MHz
AM (MW) 522 kHz to 1 620 kHz
(LW) 144 kHz to 279 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 30 dB
Capture Ratio 1.5 dB
MW Tuner Sensitivity 20 µV
Selectivity 35 dB
LW Tuner 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
Dimensions (W ×H ×D) Installation Size (approx.) 182 mm ×52 mm ×150 mm
Panel Size (approx.) 188 mm ×58 mm ×11 mm
Mass (approx.) 1.4 kg (excluding accessories)

(No.MA245)1-7
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.

1-8 (No.MA245)
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
Wires Push switch
Pickup
Base board
Pickup
Connector
Flexible wire
Frame CD mechanism
assembly

(No.MA245)1-9
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

1-10 (No.MA245)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 DIFFERENT POINT
2.2 CD MECHANISM
For the CD mechanism, please refer the mechanism manual TN2007-1001 (No.MY003).
KD-AR370 KD-G320 KD-G421 KD-G424 KD-G425 KD-G427
YES YES NO NO NO NO
YES YES
YES YES YES YES YES
NO
NO
NO NO NO
YES YESNO NO NONO
REMOTE
CONTROLLER

(No.MA245)1-11
SECTION 3
DISASSEMBLY
3.1 Main body section
3.1.1 Removing the front panel assembly
(See Fig.1)
(1) Push the detach button in the lower right part of the front
panel assembly and remove 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 two
joints aon the left side, two joints bon the right side and
joint con the back side of the main body, then remove the
bottom cover from the main body.
Note:
When releasing the joints using a screwdriver, do not damage
the main board.
Fig.2
3.1.3 Removing the front chassis assembly
(See Fig.3)
• Remove the front panel assembly and bottom cover.
(1) Remove the two screws Aon the both sides of the main
body.
(2) Release the joint dand joint eon the both sides of the main
body, then remove the front chassis assembly toward the
front.
Fig.3
Detach button
Front panel assembly
Bottom cover
Joint b
Joint b
Joint c
Joint a
Joint a
Joint d
Front chassis assembly
A
Joint e

1-12 (No.MA245)
3.1.4 Removing the side panel
(See Fig.4)
Reference:
Remove the front panel assembly as required.
(1) Remove the screw Band two screws Cattaching the side
panel on the left side of the main body.
(2) Remove the side panel from the main body.
Fig.4
3.1.5 Removing the rear bracket
(See Fig.5)
• Remove the bottom cover.
(1) Remove the three screws D, three screws Eand two
screws Fattaching the rear bracket on the back side of the
main body. [For KD-AR370, KD-G320, KD-G424, KD-
G425, KD-G427]
(2) Remove the four screws D, three screws Eand two screws
Fattaching the rear bracket on the back side of the main
body. [For KD-G421]
(3) Remove the rear bracket.
3.1.6 Removing the main board
(See Figs.5 and 6)
• Remove the front panel assembly, bottom cover and side pan-
el.
Reference:
Remove the front chassis assembly as required.
(1) Remove the three screws Dattaching the rear bracket on
the back side of the main body. [For KD-AR370, KD-G320,
KD-G424, KD-G425, KD-G427] (See Fig.5.)
(2) Remove the four screws Dattaching the rear bracket on
the back side of the main body. [For KD-G421] (See Fig.5.)
(3) Remove the two screws Gattaching the main board. (See
Fig.6.)
(4) Disconnect the connector CN501 on the main board from
the main body and take out the main board with the rear
bracket. (See Fig.6.)
Reference:
Remove the rear bracket from the main body as required. (See
"3.1.5 Removing the rear bracket".)
Fig.5
Fig.6
Side panel
CBC
[For KD-AR370,KD-G320,KD-G424,KD-G425,KD-G427]
[For KD-G421]
DD
EFE
Rear bracket F
EF
DD
E
Rear bracket F
Main board
G
G
CN501
Rear bracket

(No.MA245)1-13
3.1.7 Removing the CD mechanism assembly
(See Fig. 7)
• Remove the front panel assembly, bottom cover, side panel,
rear bracket and main board.
Reference:
Remove the front chassis assembly as required.
(1) Remove the three screws Hattaching the CD mechanism
assembly on the top chassis.
(2) Take out the CD mechanism assembly.
Fig.7
3.1.8 Removing the switch board
(See Figs.8 to 10)
• Remove the front panel assembly.
(1) Remove the four screws Jon the back side of the front pan-
el assembly. (See Fig.8.)
(2) Release the joints fand remove the rear cover. (See Fig.9.)
(3) Release the joint gand take out the switch board from the
front panel assembly. (See Fig.10.)
Fig.8
Fig.9
Fig.10
H
H
CD mechanism assembly Top chassis
J
J
J
Joints f
Joints f
Joints fJoints f
Rear cover
Switch board Joint g Front panel assembly

1-14 (No.MA245)
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
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(10.5 to 16V)
Load impedance 20KΩ(2 Speakers connection)
Output Level Line out 2.0V (Vol. MAX)
Heat sink
Rear bracket
EXTSH002-22P
Extension cable

(No.MA245)1-15
SECTION 5
TROUBLESHOOTING
5.1 Feed section
5.2 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
28 of IC501?
YES YES Check IC501.
NO
Check the connections
of CD8V power supply.
NO
Is the voltage output at
pin 7 of IC521?
Check the connections
between IC501 and
IC521.
YES
NO
Is the power supply
present at pin 37,
pin 49, pin 53, pin 56
and pin 72 of IC521?
YES Check IC521.
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
Is the voltage output at
pin 13 of IC521?
NO
YES Check the connections
between IC501 and
IC521.
Is the power supply
present at pin 3, pin 12
and pin 21 of IC501?
YES Check IC501.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 37,
pin 49, pin 53, pin 56
and pin 72 of IC521?
YES Check IC521.
NO
Check the connections
of CD8V power supply.

1-16 (No.MA245)
5.3 Spindle section
5.4 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 pin 39 of IC521?
YES
Check the spindle motor
and its wiring.
Is the RF waveform at
pin 39 of IC521 distorted?
Proceed to the Tracking
section
Check the circuits in
the vicinity of IC521
or the pickup.
YES
NONO
YES
NO
Is the voltage input at pin
17 of IC501?
YES
NO
Is the voltage output at
pin 5 of IC521?
Check the connections
between IC501 and
IC521.
YES
NO
Is the power supply
present at pin 3, pin 12
and pin 21 of IC501?
YES Check IC501.
NO
Check the connections
of CD8V power supply.
Is the power supply
present at pin 37,
pin 49, pin 53, pin 56
and pin 72 of IC521?
YES Check IC521.
NO
Check the connections
of CD8V power supply.
When the disc is rotated
at first:
Approx. 1.2V
Is the tracking error
signal output at pin 26
of IC521?
Replace IC521 or repair
the malfunction
connection point
YES
NO
Check the pickup and
its connections.

(No.MA245)1-17
5.5 Signal processing section
5.5.1 Signal processing section (For KD-AR370,KD-G320,KD-G424 and KD-G425)
5.5.2 Signal processing section (For KD-G421 and KD-G427)
No sound from either
channel.
Is 9V present at pin 24
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?
Normal
YES
NO
YES
NO
Check IC581 and its
peripheral circuits.
NO
Is 9V present at pin 13
of IC901?
YES
Check the connections
between pin 24 of IC161
and pin 13 of IC901.
NO
Check IC901 and its
peripheral circuits.
Is the audio signal output
at pin 18 and pin 19 of
IC161 during playback?
YES
NO
Check IC161 and its
peripheral circuits.
YES
Check the power
amplifier IC301.
Is the audio signal output
at pin 18 and pin 19 of
IC171 during playback?
No sound from either
channel.
Is 9V present at pin 32
of IC171?
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?
Normal
YES
NO
YES
NO
Check IC581 and its
peripheral circuits.
NO
Is 9V present at pin 13
of IC901?
YES
Check the connections
between pin 32 of IC171
and pin 13 of IC901.
NO
Check IC901 and its
peripheral circuits.
YES
NO
Check IC171 and its
peripheral circuits.
YES
Check the power
amplifier IC301.

1-18 (No.MA245)
5.6 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.
5.7 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 test point or
ARF test point.
Finish.

(No.MA245)1-19
5.8 16 PIN CORD DIAGRAM (for KD-AR370 and KD-G320)
CAUTION!
REMOTE
OUTPUT ONLY
GND
16 YL
8 BK
7 RD
3 GN
11 GN/BK
2 VI
10 VI/BK
4 WH
12 WH/BK
1 GY
9 GY/BK
5 BL/WH
MEMORY
GND
ACC
RL+
RL-
RR+
RR-
FL+
FL-
FR+
FR-
REMOTE
13 BR TEL
RR
FR
FL
RL
REMOTE
ACC
GND
MEMORY
Rear Right
Front Right
Front Left
Rear Left
Remote out
ACC Line
Ground
Memory Backup Battery +
Telephone muting
TEL
Black
RD
BK
Red
BL
Blue
WH
White
GN Green
VI Violet
GY Gray
Yellow
YL
BR
Brown
8
7
6
5
16
15
14
13
4
3
2
1
12
11
10
9
BK
RD
NC
BL/WH
WH
GN
VI
GY
YL
NC
NC
BR
WH/BK
GN/BK
VI/BK
GY/BK

1-20 (No.MA245)
5.9 16PIN CORD DIAGRAM (for KD-G421 and KD-G427)
8
7
6
5
4
3
2
1
16
15
14
13
12
11
10
9
BK
RD
NC
BL/WH
WH/BK
GN/BK
VI/BK
GY/BK
WH
GN
VI
GY
YL
NC
NC
BR
1
3
5
7
2
4
6
8
NC
NC
BL/WH
RD
BR
YL
NC
BK
1
3
5
7
2
4
6
8
VI
GY
WH
GN
VI/BK
GY/BK
WH/BK
GN/BK
7 RD
16 YL
8 BK
5 BL/WH
13 BR
3 GN
11 GN/BK
2 VI
10 VI/BK
4 WH
12 WH/BK
1 GY
9 GY/BK
RD RD 7
YL 4
8
5
2
8
5
2
7
1
6
3
4
BK
RD
BL
WH
BR
Black
Red
Blue
White
Brown
GN Green
VI Violet
GY Gray
YL Yellow
RR Rear Right
FR Front Right
FL Front Left
RL Rear Left
REMOTE
Remote
ACC
TEL
ACC Line
Telephone Muting
GND Ground
MEMORY
Memory Backup Battery+
ILL
Illuminations Control
ANT Auto Antenna