JVC KD-SX950 User manual

SERVICE MANUAL
CD RECEIVER
No.49539
Feb. 2000
COPYRIGHT 2000 VICTOR COMPANY OF JAPAN, LTD.
This service manual is made from 100% redycled paper.
Printed in Japan
200002(V)
VICTOR COMPANY OF JAPAN, LIMITED
MOBILE ELECTRONICS DIVISION,10-1,1Chome,Ohwatari-machi,maebashi-city,Japan
KD-SX950
(No.49539)
KD-SX950
KD-SX950
Area Suffix
J ---- Northerm America
Contents
Safety precaution  1-2
Instructions 1-3~16
Disassembly method 2-1
Adjustment method 2-6
Flow of functional operation
until TOC read  2-7
Maintenance of laser pickup 2-9
Description of major ICs 2-10
Block diagram  2-26
Standard schematic diagrams 2-27
Printed circuit boards 2-29~31
Parts list 3-1~
CD
DISP
SCM
RPT
SSM
BBE
MO
RND
789
CD CHANGER CONTROL
10 11 12
INT
CD -CH
FM/AM
/I
ATT
/
SCAN

!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.
Safety precaution
!CAUTION Please use enough caution not to see the beam directly or touch it in case of an
adjustment or operation check.

Disasembly method
Removing the front panel unit
1.Press the Eject button to open the front panel unit
(See fig 1)
2.Push and open the right and left open/close shaft arms
outward to remove the shaft.(See fig 2)
3.Remove the front panel unit from the same side as the
shaft was removed.
1.Remove the front panel unit.
2.Remove the two screwsAbsecuring the front chassis
assembly.(See fig 3)
3.Remove the four ribsaasecuring the front chassis
assembly to the chassis.(See fig 4)
Removing the front chassis assembly
Removing the bottom cover assembly
Turn the unit upside down,then insert and turn to
b the screwdriver to remove the bottom cover.
(See fig 5)
Fig 5
Fig 1
Eject button
Front panel unit
Fig 2
Open/close
shaft arm
Fig 3 A
a
Fig 4 a
b
bb
b

1.Remove three screws Eretaining the rear panel to the
chassis
2.Remove one screw Cretaining the IC to the heat sink.
3.Remove two screws Dretaining the main bord.
4.Lift up the main board to remove it.
5.Remove two screws Bto remove the heat sink.
Removing the rear brackt (See fig7)
1.Remove one screw I to remove the IC bracket.
2.Remove one screw Fto remove the line-out jack.
3.Remove one screw G to remove the antenna jack.
4.Remove one screw Hto remove the connector.
5.Remove one screw Lto remove the connector.
CD mechanism assembly (See fig8)
Remove three mechanism mounting screws Jretaining the
top cover.
Front panel unit (See fig9)
Remove five screws Kretaining the rear cover.
Removing the main board(wiht rear panel)
(See fig6.7)
Fig 9
Fig 8
J
JJ
B
B
C
Fig 6
KK
KKK
E
G
Fig 7
E
EI
LLHF
DD

Unsolder the part f and g on the CD mechanism
control board.
Remove the stator fixing the CD mechanism control
board and the damper bracket (To remove the stator
smoothly, pick up the center part).
Remove the screw F attaching the CD mechanism
control board.
Remove the CD mechanism control board in the
direction of the arrow while releasing it from the two
damper bracket slots i and the front bracket slot j.
Disconnect the flexible wire from connector on the
pickup unit.
Removing the CD mechanism control
board(See Fig.1 and 2)
Turn the FD gear in the direction of the
arrow to move the entire pickup unit to
the appropriate position where the
flexible wire of the CD mechanism unit
can be disconnected easily (Refer to
Fig.2).
ATTENTION:
Fig.1
Fig.2
Fig.3
Fig.4
Front bracket
CD mechanism
control board
Shift the lock
Flexible wire
Pickup unit
FD gear
CD mechanism control board
Loading motor Front bracket
Front bracket Pull outward
Pull outward
Flame
Damper bracket
mm
h
i
g
f
II
I
CD mechanism ass’y
Fj
k
G
k
G

Prior to performing the following procedure, remove
the CD mechanism control board.
Remove the two springs k attaching the CD mechanism
ass’y and the front bracket.
Remove the two screws G and the front bracket
while pulling the flame outward.
Remove the belt and the screw H from the loading
motor.
*
1.
2.
3.
Removing the loading motor
(See Fig.3 to 5)
Prior to performing the following procedure, remove
the CD mechanism control PWB and the front
bracket (loading motor).
Remove the three screws I and the damper bracket.
Raise the both sides fix arms and move the fix plates
in the direction of the arrow to place the four shafts l
as shown in Fig.8 and 9.
Remove the CD mechanism ass’y and the two
springs m attaching the flame.
Remove the two screws J and both sides rear
damper brackets from the dampers. Detach the CD
mechanism ass’y from the left side to the right side.
*
1.
2.
3.
4.
Removing the CD mechanism ass’y
(See Fig.1, 6 to 9)
The CD mechanism ass’y can be
removed if only the rear damper
bracket on the left side is removed.
ATTENTION:
Fig.5
Fig.6
Fig.7
Fig.8
Fig.9
Rear damper bracket
Fix arm (R)
Damper
H
II
Loading motor
Belt
Damper bracket
CD mechanism ass’y
Flame
m
m
I
I
Fix plate (L)
l
l
Rear damper bracket
Fix arm (L)
Damper
J
Fix plate(R)
J
l
l

Prior to performing the following procedure, remove
the CD mechanism control board, the front bracket
(loading motor) and the CD mechanism ass’y.
Remove the two screws K and the feed motor ass’y.
*
1.
Removing the feed motor ass’y
(See Fig.10)
*Prior to performing the following procedure, remove
the CD mechanism control board, the front bracket
(loading motor), the CD mechanism ass’y and the
feed motor ass’y.
Detach the FD gear part of the pickup unit upward.
Then remove the pickup unit while pulling out the
part n of the FD screw.
*
1.
Remove the screw L attaching the nut push spring
plate and the pickup mount nut from the pickup unit.
Pull out the FD screw.
2.
Removing the pickup unit
(See Fig.10 and 11)
When reattaching the pickuap unit,
reattach the part o of the pickup unit,
then the part n of the FD screw.
ATTENTION:
Prior to performing the following procedure, remove
the CD mechanism control board, the front bracket
(loading motor), the CD mechanism ass’y and the
feed motor ass’y.
Turn up the CD mechanism ass’y and remove the
two springs p on both sides of the clamper arms.
Open the clamper arm upward.
Turn the turn table, and remove the two screws M
and the spindle motor.
*
1.
2.
Removing the spindle motor
(See Fig.12 and 13)
Fig.10
Fig.11
Fig.12
Fig.13
Spindle motor
pp
Pickup unit
Part n
FD screw
Feed motor ass’y
FD gear Pickup unit
Part O
K
Nut push spring plate
Pickup mount nut
Pickup unit
FD screw
L
M
M

Adjustment method
Test instruments required for adjustment
1. Digital oscilloscope (100MHz)
2. AM Standard signal generator
3. FM Standard signal generator
4. Stereo modulator
5. Electric voltmeter
6. Digital tester
7. Tracking offset meter
8. Test Disc JVC :CTS-1000
9. Extension cable for check
EXTGS004-26P 1
Standard measuring conditions
Power supply voltage DC14.4V(10.5~16V)
Load impedance 20Kohm(2 Speakers connection)
Output Level Line out 2.0V (Vol. MAX)
How to connect the extension cable for adjusting
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.
Standard volume position
Balance and Bass &Treble volume : lndication"0"
Loudness : OFF
BBE : OFF
Frequency Band
FM 87.5MHz ~ 108.0MHz
MW 522kHz ~ 1620 kHz
LW 144kHz ~ 279kHz
EXTGS004-26P

Power ON
 Set Function to CD
Play
Jump to the first track
TOC readout
Tracking loop closed
Disc rotates
Disc inserted
YES
YES
Laser emitted
Pickup feed to the inner area
Focus search
RF signal eye-pattern
opens
RF signal eye-pattern
remains closed
"No disc"
display
• When correctly focused
 Focus Servo Loop ON
• When the laser diode correctly
emits
Microprocessor
commands
Rough Servo Mode
CLV Servo Mode
(ProgramArea)
CLV Servo Mode
(Lead-In Area;
Digital: 0)
• RF signal
Flow of functional operation until TOC read
• When the pickup correctly moves
to the inner area of the disc
TERMINAL
Microprocessor
commands
FMO
TC9462 "53"
FEED MOTOR
+TERMINAL
IC581 "5"
REST SW
• When the disc correctly rotates
Tracking Servo Loop ON
Servo CLV
Rough
Servo
AccelerationAcceleration
Microprocessor
commands
Spindle
motor (-)
IC581 "7"
0.5 Sec 0.5 Sec

Feed Section
Focus Section
Tracking Section
Spindle Section
Is the voltage output at
IC521 pin "53" 5V or 0V?
Check the feed motor.
Is 4V present at both
sides of the feed motor?
Is the wiring for IC521
(90) ~ (100) correct?
Check IC581.
Is 6V or 2V present at
IC581 "5" and "6"?
Is 5V present at IC581
pin "11"?
Check the feed motor
connection wiring.
Check the vicinity of
IC521.
Check CD 9V
and 5V.
YES
YES
YES
NONO
NO
NO
NO
YES
YES
When the lens is
moving:
Check the circuits in
the vicinity of IC581
pins "15" ~ "18".
Check the pickup and
its connections.
NO
YES
YES
YES
Does the S-search
waveform appear at
IC581 pins "17" and "18"?
Is the disk rotated?
Does the RF signal
appear at TP1?
Is 4V present at IC581
pins "7" and "8" ?
Check the spindle motor
and its wiring.
Is 4V present at IC521
pin "55" ?
Check the vicinity of
IC581.
Check IC501 and
IC521.
YES
NO
NO
NO
NO NO
YES
YES
YES
Check the circuits in the
vicinity of IC501 "19" ~
"24" or the pickup
Is the RF waveform at TP1
distorted?
Proceed to the Tracking
section
When the disc is rotated
at first:
Check the circuit in the
vicinity of IC501 pins
"2" ~ "12".
Check IC521.
Check the pickup and
its connections.
YESYES
YES
Is the tracking error signal
output at IC501 "12"?
Approx. 1.2 V
4V