JVC CH-X550 User manual

SERVICE MANUAL
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD. No.49787
2003/01
CH-X550
CD CHANGER
49787200301
CH-X550
TABLE OF CONTENTS
1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Area Suffix
E ------- Continental Europe

CH-X550
1-2 (No.49787)
SECTION 1
Important Safety 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.

CH-X550
(No.49787)1-3
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 DVD 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) I t 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 CDpickup 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

CH-X550
1-4 (No.49787)
SECTION 2
Disassembly method
2.1 Replacement of the pickup
(1) After removing the exterior (top and bottom).
(2) Proceed to the pickup replacement section.
(3) When applying grease, refer to the exploded view.
Use new grease.
2.2 Mechanism section
(1) Remove the exterior (required section only).
(2) The mechanism section is designed so that each unit can
be removed separately.
(3) When reassembling, refer to the assembling precautions
(Use new grease when applying grease.)
2.3 Exterior section
2.3.1 Removing the bottom cover and front panel assembly
(See Fig.1 to 4)
(1) Remove the two screw Ato unlock the mounting direction
knob located on the side of the main unit.
(2) Turn the mounting direction knob in the direction of the ar-
row using a coin, etc. to remove it. (The knob can be re-
moved only when it is set to this position.)
(3) Remove the four top cover fixing screws Bat the triangle
marks on the side of the main unit. (Perform the same op-
eration on both sides.)
(4) Turn the unit upside down so the bottom surface is facing
upward.
(5) Lift the rear edge of the bottom cover slightly and lift the
side by grasping the DIN jack section on the side panel,
then turn it toward the front (raise upward) to remove the
bottom cover.
(6) Unhook the four catches located on both sides of the front
panel, and turn the front panel toward the top cover (lower
down) to remove the front panel.
Fig.1
Fig.2
Fig.3
Fig.4
A
B
Remove A and turn in
the direction of the arrow.
B
B
B
Bottom cover
Knob
Remove A and turn in
the direction of the arrow
BB
A
B
B
Bottom cover
Knob
The front panel can be
separated by raising the cover.
Slightly lift the jack
section to remove.
Bottom cover
Unhook catches
Unhook catches
Front panel

CH-X550
(No.49787)1-5
2.3.2 Removing the top cover
(See Fig.5 to 9)
(1) Remove the four damper bracket fixing screws Cto re-
move the damper brackets.
(2) Pull out the dampers, being careful not to damage them.
When reattaching a damper, insert your finger to push out
the center of the damper to mount it on the damper shaft,
as shown in Fig. 6-1.
(3) Turn the damper spring bracket toward the top at a right an-
gle as shown in Fig. 7, then push down the lower side of the
damper spring bracket to lift it off.
(4) Remove the three fixing screws Dand Eon the DIN jack
board assembly.
(5) Lift the changer unit upward.
(6) Remove the damper springs from the mechanism chassis
if required. To reassemble, refer to the diagram below.
Fig.5
Fig.6
Fig.6-1
Fig.7
Fig.8
Fig.8-1
Fig.9
C
C
Damper
Damper bracket
Damper
Damper bracket
C
C
Damper
Damper bracket
Damper bracket
Damper
Apply alcohol to the shaft then immediately
attach the damper. (After attaching, check
that the shaft is correctly inserted.)
Push out with your finger
before attaching
Damper shaft
Damper
Turn to the top position (at a right angle),
then push down to lift off.
Damper spring bracket
Lift the changer unit upward
How to attach the damper springs
Silver
(mechanism
side)
Black
(magazine
side)
Mechanism
Chassis
Damper
spring
Damper
spring
Remove the flexible ribbon
wire if required
E
E
D
DIN jack board

CH-X550
1-6 (No.49787)
2.3.3 Removing the fittings
(See Fig.10)
(1) Remove the fixing screw F.
(2) Unhook the two catches aon the top edge of the fitting,
then unhook the two catches bat the left/right bottom edg-
es.
Fig.10
2.3.4 Removing the main PCB assembly (See Fig.11)
(1) Remove the power IC fixing screw G.
(2) Remove the four screws Hsecuring the main board as-
sembly.
(3) Disconnect position motor wire connector CN504 from the
main board assembly.
(4) Disconnect sensor board assembly wire connector CN601
from the main board assembly.
(5) Remove the flexible ribbon wire from CN502 on the
traverse mechanism board assembly. When reinstalling
the board boards, refer to the reassembling procedures for
protecting switches, etc.
Fig.11
Catches a
Catches b
Fitting
F
H
CN601
CN504
CN502
H
G
H
Main board

CH-X550
(No.49787)1-7
2.4 CD mechanism assembly
2.4.1 Sensor assembly unit
(See Fig.1)
(1) Remove the two screws Isecuring the sensor assembly
unit.
(2) Unhook the spring on the back of the sensor assembly unit
from the holes on the chassis.
2.4.2 Magazine lock arm
(See Fig.1 and 2)
(1) Remove the magazine lock spring from the front side of the
chassis.
(2) Remove the poly-washer csecuring the magazine lock
arm.
(3) Turn the magazine lock arm in the direction of the arrow un-
til the notch is at the dposition to remove it from the chas-
sis.
Fig.1
Fig.2
2.4.3 Positioning motor assembly
(See Fig.3)
(1) Remove the two screws Jsecuring the positioning motor.
(2) Slightly lift the positioning motor assembly to remove it
from the two burrs on the chassis.
Fig.3
Sensor assembly I
Spring
I
Rear
Magazine lock spring
Poly-washer c
d
Positioning
motor assembly
J

CH-X550
1-8 (No.49787)
2.4.4 Rear slider
(See Fig.4)
(1) Position the unit with the front section facing down. Rotate
the third gear located on the back of the main unit in the di-
rection of the arrow (clockwise).
(2) Shift the rear slider in the direction of the arrow and remove
it at the rear slider mounting position (at the widest hole).
Fig.4
2.4.5 Front slider
(See Fig.5)
(1) Position the unit with the rear section facing down. Rotate
the third gear located on the bottom of the unit in the direction
of the arrow (clockwise) until the front slider is shifted to the
outermost position.
(2) Remove the E-washer securing the front slider to remove
the front slider from the chassis
Fig.5
2.4.6 Top plate
(See Fig.6 and 7)
(1) Remove the nine screws K securing the top plate.
(2) Disconnect the section eattached to the rear of the unit,
then lift the top plate slightly.
(3) Slide the top plate toward the rear of the unit to remove the
upper rod from the top plate.
Fig.6
Fig.7
Can be removed at the stud position
(at the widest hole) Remove
Shift
Third gear
Rear slide
r
Remove the E-washer
Third gear
Front slide
r
Slide and remove the rod inside
Slide
Top plate
K
K
K
Rod
After lifting e
Remove
K
Top plate

CH-X550
(No.49787)1-9
2.4.7 Lifter unit
(See Fig.8 and 9)
(1) Unhook the elevator spring located on the front side of the
unit. (Be sure to first unhook the spring from the lifter side
as shown in the upper part of the diagram.)
(2) Lift the lifter unit upward, then remove the lower rod to re-
move the lifter unit from the chassis.
Fig.8
Fig.9
2.4.8 Lifter bracket
(See Fig.10)
(1) Remove the two lifter bracket fixing screws L located on the
back of the lifter unit.
(2) Remove the lower rod.
Fig.10
2.4.9 Side bracket and traverse mechanism assembly
(See Fig.11)
(1) Remove the two side bracket unit fixing screws Mto dis-
connect the side bracket unit from the lifter unit.
(2) Remove the three shafts on the traverse mechanism as-
sembly from the lifter unit.
CAUTION:
For reassembling, refer to the reassembling procedures.
Fig.11
Unhook this part first
Proper
orientation
Spring
Lift up the lifter unit
Lower rod
Lifter unit
L
L
Lifter bracket
Remove from the lifter unit
Remove from the
lifter unit
M
M
Lifter unit
Side bracket
Traverse mechanism
assembly

CH-X550
1-10 (No.49787)
2.4.10 Removing the mechanism board / pickup assembly
(See Fig.12 to 15)
(1) Remove the three screws N fixing the mechanism board on
the back of the traverse mechanism.
(2) Disconnect the two feed motor wires (blue and white), two
spindle motor wires (red and black) and two tray motor wires
(brown and black) that are soldered to the mechanism
board.
(3) Short-circuit the grounding point on the mechanism board.
Move the mechanism board without disconnecting the wire
from connector CN501. Solder the short circuit round on
the pickup assembly.
(4) Disconnect the wire from connector CN501 on the mech-
anism board.
(5) Remove the screw O to remove the feed motor assembly.
(6) Remove the screw Pto remove the shaft holder retaining
the feed slide shaft assembly and the middle gear.
(7) Move the middle gear.
(8) Move the pickup assembly upward from the gear section
and remove it from the traverse chassis assembly.
(9) Remove the two screws Qto remove the rack arm.
(10) Pull out the feed slide shaft assembly.
(11) Remove the screw Rto remove the spring.
CAUTION:
To reattach the mechanism board, connect the pickup flex-
ible wire to connector CN501 on the mechanism board be-
fore unsoldering the short circuit round. Subsequently, fix
the mechanism board using screws.
Fig.12
Fig.13
Fig.14
Fig.15
Brown and black
N
N
Red and black
Blue and white
Mechanism board
CN501
Short circuit round
(Grounding point)
Pickup
Flexible wire
Grounding point
Pickup assembly
Shaft holder
Feed slide
shaft assembly
Middle gear
Feed motor
P
O
Chassis
Remove gears and
motors only when
required.
Rack arm Pull out
R
Q
Spring

CH-X550
(No.49787)1-11
2.4.11 Tray motor
(See Fig.16 and 17 )
(1) Remove the two screws Ssecuring the tray motor.
(2) Remove the two screws Tto remove the tray motor as-
sembly from the tray motor holder.
Fig.16
Fig.17
2.4.12 Separation of the chassis (L) assembly and chassis (R) assembly
(See Fig.18 )
(1) Remove the two screws Uretaining the chassis (L) and (R)
assemblies.
(2) Slide the chassis (L) assembly toward the front and detach
it, then remove the chassis (L) upward.
Fig.18
Tray motor assembly
SS
Tray motor
Tray motor holder
T
Front side
U
U
Slide and remove upward
as shown by the arrow
Chassis (L) assembly
Chassis (R) assembly

CH-X550
1-12 (No.49787)
2.4.13 Precautions on reassembling
CAUTION:
When reassembling, also refer to the disassembling proce-
dures.
2.4.13.1 Mounting the traverse mechanism
(See Fig.19 to 23)
(1) When mounting the pickup assembly, attach the feed slide
shaft assembly to the traverse chassis.Apply E-JC-525
grease to the shaft.
(2) Mount the middle gear and the feed slide shaft to the
traverse chassis and secure them with the screw Pthrough
the shaft holder.
(3) Before mounting the mechanism board, move the pickup to
the outer edge position, then secure the board assembly
using the screw N.
At this time, check that the rest switch is correctly placed.
(4) To mount the rack arm, first move the pickup to the middle
position and secure it with the screws Q.
CAUTION:
To reattach the mechanism board, connect the pickup flexible
wire to connector CN501 on the mechanism board before un-
soldering the short circuit round. Subsequently, fix the mech-
anism board using screws.
Fig.19
Fig.20
Fig.21
Fig.22
Fig.23
Pickup assembly
Attached to chassis
Shaft holder
Middle gear
Motor
Chassis
Mounting the
feed motor assembly
P
Feed slide shaft
(half coated with grease)
Pickup assembly
Attached to chassis
Shaft holder
Middle gear
Motor
Chassis
Mounting the
feed motor assembly
P
Feed slide shaft
(half coated with grease)
Rack arm
Q
Move the pickup to
the middle position
Mechanism board
N
N
N
CN501
Short circuit round
(Grounding point)
Pickup
Flexible wire

CH-X550
(No.49787)1-13
2.4.13.2 Mounting the lifter unit
(See Fig.24 to 26)
(1) Insert the shafts f of the traverse mechanism assembly into
the slide grooves gon the lifter unit.
(2) Shift the hook of the lifter unit to the edge, and shift the slid-
ing lever inside the side bracket unit to the edge as well.
(3) With each hole and lever shifted to the edge, mount the lift-
er unit and side bracket unit from the side.
(Check each attached section, and check that the two
shafts hof the lifter unit are correctly inserted into the holes
iof the side bracket unit. After mounting, check that the le-
vers move together. )
(4) Turn the lifter unit upside down.
As shown in Fig. 35, slide the lever 30mm away from the
edge, then mount the lifter bracket assembly.
Fig.24
Fig.25
Fig.26
f
f
f
h
Attach
i
g
g
g
Lifter unit
M
Side bracket
Traverse mechanism
assembly
Shift inside by approx. 30 mm
Expanded view
Lifter bracket

CH-X550
1-14 (No.49787)
2.4.13.3 Connection of the chassis (L) assembly and chassis (R) assembly
(See Fig.27 to 29)
(1) Attach the lower rod to the chassis (R) assembly. While
shifting the rod toward the front side, mount the rod on the
lifter unit.
With the rod mounted, place the lifter unit on the chassis
(R) assembly.
(2) Combine the chassis (L) and (R) assemblies so that the
hook section j of the chassis (L) assembly is inserted into
the notch of the chassis (R) assembly by sliding it from the
front side.
(3) After engaging, secure with the two screws U.
(4) Attach the tension spring between the lifter unit and the
chassis.
Fig.27
Fig.28
Fig.29
Lower Rod
Lifter unit
Notch
Attached
j
Slide to engage
Combine with (R) chassis
Set last (lifter side)
Proper
orientation
Tension spring
Set first
(chassis side)
U
Chassis (L) assembly
U
Chassis (R) assembly

CH-X550
(No.49787)1-15
2.4.13.4 Mounting the top plate
(See Fig.30 to 33)
(1) Mount the upper rod on the lifter side l and set it on the rear
of the top plate, then mount the other end of the upper rod
to m.
(2) Check that the five points (n, o, p, sand r) are correctly po-
sitioned.
When mounting section s, set it so that section t of the lifter
unit is pinched by the bending section of the top plate.
(3) Secure the top plate with six fixing screws K.
Fig.30
Fig.31
Fig.32
Fig.33
Upper rod
m
l
K
K
K
Top plate
Section t
Lifter Unit
Point r
Expanded view of mounting s
nops
r

CH-X550
1-16 (No.49787)
2.4.13.5 Mounting the front slider and rear slider
(See Fig.45 and 46)
(1) Position the unit with the rear side facing down, then rotate
the third gear in the direction of the arrow (clockwise) until
the lift arm comes to the position at which the holes are ex-
posed, as shown in Fig. 34
(2) Mount the front slider from the top.
Rotate the third gear counterclockwise until the hole of the
slider is lined up with the right hole of the stud, as shown in
Fig. 34
(3) Mount the E-washer on the shaft.
(4) Position the unit with the front side facing down, then
mount the rear slider. Check that the u, vand wpositions
are correctly mounted as shown in Fig. 35.
(5) Rotate the third gear in the direction of the arrow (counter-
clockwise) until the lifter unit is at the top position.
Fig.34
Fig.35
Stud
E-Washer
Front slider
Check after mounting
Set so the holes
are exposed
Position so
that the stud
and right hole
are lined up
Rotate the third gear
to move the slider
Rotate until the
holes are lined up
uvw
Rotate the third gear
to move the slider

CH-X550
(No.49787)1-17
2.4.13.6 Mounting the sensor board assembly
(See Fig.36)
(1) Attach the longer spring to the white resin, and attach the
shorter spring temporarily to the sensor assembly bracket.
(2) Mount the sensor assembly so that the shaft of the lift arm
is inserted into the longer hole on the white resin located on
the back of the sensor board assembly.
(3) Attach the shorter spring to the hook of the lift arm.
Fig.36
2.4.13.7 Mounting the main PC board assembly
(See Fig.37)
(1) Rotate the third gear clockwise until section x of the front
slider and the third hole from the right are lined up.
(Be sure to set properly. If incorrectly set, the switches on
the board assembly may be damaged.)
(2) After they are correctly positioned, mount the main board
assembly.
Fig.37
Sensor assembly fixing screws
A
ttach
temporarily
Shorter spring
Longer spring
Shorter
spring
I
I
x
Position so that the slider hole and
third hole from the right are lined up

CH-X550
1-18 (No.49787)
2.4.13.8 Pickup replacement procedure
(See Fig.38 to 44)
(1) Remove the bottom cover, front panel and top cover from
the exterior section.
(2) Unplug the flexible ribbon wire from connector CN502 on
the traverse mechanism PC board assembly.
(3) Turn the rear slider and third gear in the lifter section coun-
terclockwise until the traverse mechanism assembly is in
the lowermost (bottom) position.
(4) Unsolder the two wires (black and brown) connected to the
tray motor.
(5) Remove the two screws Mfrom the round holes on the
chassis (R) assembly to remove the lifter bracket (L).
(6) Remove the lower rod.
(7) Disconnect the two feed motor wires (blue and white), two
spindle motor wires (red and black) and two tray motor
wires (brown and black) that are soldered to the mecha-
nism board.
(8) Short-circuit the grounding point on the mechanism board.
Move the mechanism board without disconnecting the wire
from connector CN501. Solder the short circuit round on
the pickup assembly.
(9) Disconnect the wire from connector CN501 on the mecha-
nism board.
(10) Remove the three fixing screws Nfrom the round holes on
the chassis (R) assembly to remove the traverse mecha-
nism board assembly.
(11) Remove the pickup shaft holder fixing screw Pto remove
the pickup assembly.
CAUTION:
When replacing the pickup, be sure to apply counter-
measures against static electricity (grounding the opera-
tion table, wrist band and soldering iron). To remove it,
first short-circuit the grounding point on the mechanism
board, then lift the mechanism board assembly with
CN501 connected. Next, short-circuit the grounding
point on the pickup main unit, then unplug the pickup
flexible board from connector CN501.
CAUTION:
When reassembling, perform in the reverse order.
(12) Remove the two rack arm fixing screws Q.
Pull out the feed slide shaft.
Remove the shaft holder fixing screw R.
(13) When mounting the lifter bracket after replacing the pickup,
shift the lifter unit lever approx. 30 mm towards the inside,
then mount the lifter bracket.
Fig.38
Fig.39
Fig.40
Fig.41
Third gear
M
CN502
Unsolder
Lifter bracket (L)
M
Main PCB assembly
Feed moto
r
assembly
N
N
N
CN501
Tray motor
assembly
Unsolder
Traverse mechanism
board assembly
Grounding point
P
Pickup assembly
Shaft holder
Spindle motor
Short circuit round
(Drounding point)
Pickup
Flexible wire

CH-X550
(No.49787)1-19
Fig.42
Fig.43
Fig.44
Pickup
Feed slide shaft
Rack arm
R
Q
Shaft Holder
Middle gear
P
Pickup
Middle gear
Chassis
Shift approx. 30 mm
Shift approx. 30 mm
Lifter unit lever
Enlarged diagram

CH-X550
1-20 (No.49787)
SECTION 3
Adjustment
3.1 Forced eject procedures
Magazine eject does not function.
Remove the bottom cover
Disconnect the tray from the hook.
RESET (Press EJECT for 3 sec.)
Completed
Completed
Press the magazine lock lever to
eject the magazine.
Rotate the third gear clockwise
until the lifter level is below the 9th
tray position.
Place the unit with its left side
facing down and apply a slight
shock, then return the tray to the
magazine.
Rotate the third gear clockwise and
unchuck the disc.
Remove the dampers and the top
cover to take out the mechanism.
Remove the item(s) causing the
disc-jam through the clearance at
the top of the lifter.
Remove the lifter bracket (L) and
return the tray to the magazine.
Completed
YES
YES
YES
NO
NO
NO
Is the disc set in the
playing position?
Are trays stored in
the magazine?
Check visually.
Improperly positioned
Peel off the sticker on the left side
of the unit. Insert a screwdriver
and press the internal lever to
forcibly eject the magazine.
Check that the trays remain no more
than 10 mm inside the magazine.