JVC MXKA-7 Service manual
SERVICE MANUAL
COMPACT COMPONENT SYSTEM
MX-KA7
MX-KA7
CA-MXKA7SP-MXKA7 SP-MXKA7
Contents
Safety precautions ---------------------------- 1- 2
Preventing static electricity ----------------- 1- 3
Important for laser products ---------------- 1- 4
Disassembly method ------------------------ 1- 5
Adjustment method -------------------------- 1- 18
Flow of functional
operation until TOC read -------------- 1- 20
Area Suffix
JW ........ Mexico, Panama
Maintenance of laser pickup -------------- 1- 21
Replacement of laser pickup -------------- 1- 21
Description of major ICs ------------------- 1- 22
Wiring connection ---------------------------- 1- 33
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD.
No. MB039
2003/11
MX-KA7
1. This design of this product contains special hardware and many circuits and components specially for
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the
3. Many electrical and mechanical parts in the products have special safety-related characteristics. These
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be
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
Safety Precautions
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.
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.
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 (
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.
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.
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 ACtype 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 each exposed
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.).
) on the Parts List in the Service Manual. The use of a substitute replacement
AC VOLTMETER
(Having 1000
ohms/v
olts,
or more sensitivity)
0.15 F AC TYPE
Place this
probe on
1500 10W
each exposed
metal part.
1-2
Good earth ground
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.
!
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.
Preventing static electricity
1. Grounding to prevent damage by 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.
2. About the earth processing for the destruction prevention by static electricity
In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity
of the work environment.
Be careful to use proper grounding in the area where repairs are being performed.
2-1 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.
2-2 Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
(caption)
Anti-static wrist strap
MX-KA7
Conductive material
(conductive sheet) or iron plate
3. Handling the optical pickup
1. 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.)
2. Do not use a tester to check the condition of the laser diode in the optical pickup. The testers internal power
source can easily destroy the laser diode.
4. Handling the CD changer unit (optical pickup)
1. Do not subject the CD changer 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 CD changer
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.
CD changer
unit
Attention when traverse unit is decomposed
Please refer to “Disassembly method” in the text for
*
pick up and how to detach the CD changer mechanism.
1. Remove the CD changer unit.
2. Disconnect the harness from connector on the CD motor
board.
3. Solder is put up before the card wire is removed from connector
Cn601on the main board as shown in Fig.1 and Fig. 2.
(When the wire is removed without putting up solder, the
CD pick-up assembly might destroy.)
4. Please remove solder after connecting the card wire with
CN601 when you install picking up in the substrate.
Flexible cable
Fig.1
Soldering
Fig.2
1-3
MX-KA7
Important for laser products
1. CLASS 1 LASER PRODUCT
2. DANGER :
lock failed or defeated. Avoid direct exposure to beam.
3. CAUTION :
Laser Unit. Do not disassemble the Laser Unit. Replace
the complete Laser Unit if it malfunctions.
4. CAUTION :
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.
Invisible laser radiation when open and inter
There are no serviceable parts inside the
The compact disc player uses invisible
5. CAUTION :
able to function.
6. CAUTION :
of procedures other than those specified herein may
result in hazardous radiation exposure.
!
CAUTION Please use enough caution not
If safety switches malfunction, the laser is
Use of controls, adjustments or performance
to see the beam directly or touch
it in case of an adjustment or
operation check.
FUSE CAUTION
CAUTION:
REPLACE WITH SAME TYPE
AND RATING FUSE (S).
ATTENTION:
REMPLACER PAR UN(LES)
FUSIBLE(S) DE MEME TYPE
ET DE MEME VALEUR
1-4
MX-KA7
Disassembly method
Commence disassembly of the set by removing the main units and then proceed to the components
and assemblies inside the units.
Replacement of the fuses and the power IC
Top cover
CD changer unit
Front panel assembly
Chassis unit
CD changer unit
Removing the main PCB
Removing the CD changer mechanism assembly
Removing the CD pickup
Replacing the loading motor and belt of the CD changer tray
Replacing the CD tray rotor belt of CD changer, and removing the motor
Front panel assembly
Removing the cassette deck mechanism
Removing the earphone jack PCB
Removing the control/FL PCB
Removing the switch PCB and ACTIVE BASS EX. switch PCB
Removing the cassette deck main motor, and replacing the main belts
Removing the leaf switches of the cassette deck mechanism
Removing the cassette deck heads
Chassis unit
Removing the 3-pin regulator
Removing the power amp and supply PCB and the Power Trans PCB
Removing the sub power PCB
1-5
MX-KA7
<Disassembly of the main blocks of the set>
Replacement of the fuses and the power IC
Replacing the fuses (See Fig.1)
Prior to performing the following procedure, remove
the top cover.
1. Replace the fuses inside.
Replacing the heat sink cover (See Fig.3)
1. Remove four screws B from the rear panel.
2. Pull the heat sink cover outward.
[Caution]
Be sure to use fuses with the specified
ratings.
Fuse (F952)
1.6A 250V
Fig.1
Replacing the power IC (See Fig.2)
Prior to performing the following procedure, remove
the top cover.
Remove the two screws A from the heat sink between
1.
the power IC.
2. Remove the solder fixing the power IC.
B
Fuse (F951)
3.15A 250V
Fig.3
1-6
A
Fig.2
C
Removing the top cover
(See Fig.4 and 5)
1. Remove six screws C that retain the top cover from
the panel rear of the body.
2.
Remove six screws D that retain the top cover from
the two sides of the body.
3. Remove the top cover from the body by lifting it
toward the rear.
MX-KA7
Top cover
C
Fig.4
Right Front panel assembly
Left Front panel assembly
D
D
Fig.5
D
D
1-7
MX-KA7
Removing the CD changer unit
Prior to performing the following procedures, remove
the top cover.
(See Fig.6 to 9)
[Caution]
Although the CD mechanism unit can be
removed without removing the CD tray
panel, it is still recommended to remove it
in order to prevent damage.
a. From the front panel side of this set, push in the
sections marked with arrows and pull out the CD
tray toward the front.
b. Remove the CD tray panel by pushing both of
its extremities upward in the direction of the
arrows.
c. Push the CD tray deep into the set.
Disconnect the cord wires from the CD PCB CN703
1.
and CN203.
From the rear of the set, remove two screws E
2.
F
three screws
and four screws G on the front
panel left and right side.
3. Handle the CD changer unit rear, take out the unit.
CD tray panel
CD tray panel
Fig.7
E
Antenna
termianl
F
Aux
terminal
Fig.6
Fig.8
CD changer
unit
G
Fig.9
1-8
Removing the front panel assembly
(See Fig.10 to 11)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
1. Disconnect the parallel wire and the cord wire from
the connectors CN701, CN101 on the power amp.
PCB.
2. Remove one screws
assembly onto the bottom of the body.
3. Remove two screws I on the left and right side of the set
retaining the panel front from the bottom and then
remove then GND lug
amp and supply PCB.
4. Disengage the claws
panel assembly and then remove the assembly.
H
retaining the front panel
b
that comes from the power
c
on both sides of the front
MX-KA7
H
Fig.10
GND lug
Fig.11
er amp andPow
supply PCB
b
Claw
I
c
1-9
MX-KA7
<Disassembly of units and assembly
inside this set>
Removing the CD PCB
(See Fig.12 to 13)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
1. Disconnect the wires from CN603A, CN603B and
CN604 on the CD PCB, which is located on the
back side of the CD changer unit.
J
2. The four screws
removed.
3. Remove the CD PCB by pulling it toward the side
where the CN601 is located.
Using solder, short the CD pickup to connect to
4.
short round.
[Caution]
After re-connecting the wires, be sure to
remove the shorting solder from the GND
connection.
5. Disconnect the card wire from the connector CN601
on the main PCB and then remove the main PCB.
that retain the CD PCB should be
J
CD PCB
CD PCB
J
J
Fig.12
CN601
Short round
Fig.13
1-10
Removing the CD changer mechanism
assembly (See Fig.14 to 15)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
1. Turn the CD changer mechanism cover base and
remove the screws
changer mechanism assembly.
2. Removing four screws
holder assembly.
d
connecting the unit to the CD
e
retaining the CD mechanism
MX-KA7
CD changer
unit
[Caution]
CD changer
mechanism
assemb
ly
When replacing the CD changer mechanism
assembly, be sure not to mistake the positions
of the silver color and copper color spring.
e
e
( Silver color)
( copper color)
d
Fig.14
e
( Silver color)
Fig.15
e
( copper color)
1-11
MX-KA7
Removing the CD pickup (See Fig.16)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
Also remove the CD changer mechanism.
CD pickup
1. Widen the section
2. While keeping the section
section
g
in the direction of the arrow to remove
f
.
f
wide open, push the
the shaft, and then remove the CD pickup.
Replacing the loading motor and rotor
belt of the CD changer (See Fig .17)
Prior to performing the following procedures, remove
the top cover.
Also open the CD changer tray.
1. Remove the two screws
L
retaining the CD
changer tray loading motor.
2. Remove the two screws
M
retaining the gear
plate and take it out, after remove the rotor belt
from the pulley.
Replacing the CD turn table and remov-
ing the motor (See Fig. 19 )
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
1. Remove the one screws
table).
2. Remove the two screws
brackets on both sides of the CD changer unit.
3. Remove the stopper brackets from both sides of
the CD changer unit.
4. Pull out the CD tray from the CD changer unit, all
the way and lift the tray (u/~ ward) to remove.
5. Remove the gear and after push out the tray motor
locker and pull out the tray motor from the CD tray.
N
retaining the CD (Turn
O
retaining the stopper
f
Shaft
Fig.16
M
L
Fig.17
g
1-12
Turn table motor
, and then remove the CD tray
Motor locker
Obligue gear
Fig.18
Removing the cassette deck mechanism
(See Fig.19)
MX-KA7
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
Also remove the front panel assembly.
1. Remove six screws
Z
retaining the cassette deck
mechanism.
Removing the earphone jack PCB
(See Fig.20)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
Also remove the front panel assembly.
1. Remove the screw with the washer,
retains the earphone jack PCB.
P
that
KEY 1
PCB
Front panel
assembly
Z
Z
Fig.19
Front panel
assembly
Earphone jack
PCB
P
Removing the control/FL PCB
(See Fig.21)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
Also remove the front panel assembly.
1. Remove six screws Q that retain the control/FL PCB
from the back of the front panel unit.
Q
KEY 2
PCB
Fig.20
Front panel
assembly
Q
Control/FL
PCB
Fig.21
1-13
MX-KA7
Removing the switch PCB and sound
mode and CD function switch PCB
(See Fig.20 to 23)
Prior to performing the following procedures, remove
the top cover.
Also remove the CD changer unit.
Also remove the front panel assembly.
1. Pull out the volume control knob from the front of
the front panel assembly.(Fig.22)
2. Remove six screws
assembly.(Fig.21)
3. Remove the control/FL PCB.
4. Remove eleven screws
PCB.(Fig.20)
5. Remove two screws
and CD function (key 2) switch PCB.(Fig.21)
Q
retaining the front panel
R
retaining the switch (key 1)
S
retaining the sound mode
Front panel assembly
Volume knob
Fig.22
Fig.23
Front panel
assembly
Volume
shaft
1-14
Removing the cassette deck main motor,
and replacing the main belts
(See Fig.19, 24 and 25)
Prior to performing the following procedures, remove
the top cover and both sides board.
Also remove the CD changer unit.
Also remove the front panel assembly.
Z
1. Remove six screws
mechanism. (Fig.19)
2. Remove the cassette deck mechanism.
3. Remove two screws
the front side of the cassette deck.
retaining the cassette deck
t
retaining the main motor from
MX-KA7
Cassette deck mechanism
(Front side)
t
Fig.24
[Caution]
After attaching the main motor, check the
orientation of the motor and the polarity of
the wires.
4. From the backside of the cassette deck, remove the
main motor and two main belts.
[Caution]
The lengths of the cassette A(playback
only) and cassette B(record/play) main
belts are different. When attaching the main
belts, use the longer belt for cassette
Removing the leaf switches of the cassette
A
.
deck mechanism (See Fig. 19 and 26)
Prior to performing the following procedures, remove
the top cover and both sides board.
Also remove the CD changer unit.
Also remove the front panel assembly.
Cassette deck mechanism
(Back side)
Main belt
(For B cassette)
Fig.25
Solder side of leaf switch
Cassette deck main motor
Main belt
(For
A
cassette)
1. Remove the six screws
Z
that retain the cassette
deck mechanism. (Fig.19)
2. Remove the cassette deck mechanism.
3. Turn the cassette deck mechanism upside down.
4. Remove the solder from around the leaf switches.
5. Pull out the leaf switches from the front side of the
cassette deck mechanism.
Cassette deck mechanism
(Back side)
Fig.26
1-15
MX-KA7
Removing the cassette deck heads
Prior to performing the following procedures, remove
the top cover and both sides board.
Also remove the CD changer unit.
Also remove the front panel assembly.
(See Fig. 19 and 27)
Cassette deck mechanism
(Front side)
1. Remove six screws
Z
that retain the cassette deck
mechanism. (Fig.19)
2. Remove the cassette deck mechanism and place
it so that the front side faces up.
3. Remove the solder from the bottom side of the
head terminal and disconnect the wire.
U
4. Remove screw
5. Remove screw
that retains the head.
V
that retains the head.
6. Hold the head and slide it in the direction of the
arrow to remove it.
Removing the 3-pin regulator and bridge
diode
(See Q904, Q907, D901, D914 and Fig.28)
Prior to performing the following procedures, remove
the top cover and both sides board.
A
1. Remove two screws
2. Remove two screws
3. Remove the solder fixing the the 3-pin terminal regulator
Q904, Q907.
4. Remove the solder fixing the 4-pin bridge diode
(D901, D914).
that connect the heat sink.
W
that connect the heat sink.
PB Head REC/PB Head
V U
V U
Fig.27
AW
1-16
Fig.28
Removing the power amp and supply PCB
and the power trans PCB
(See Fig. 2, 29 to 31)
Prior to performing the following procedures, remove
the top cover and CD changer unit.
B
1. Remove four screws
2. Pull the heat sink cover outward.
3. Remove
four screws AA from the rear panel between
the heat sink holder.
4. Remove two screws X that retain the speaker terminals
and AUX terminal.
5. Remove screws
then remove the rear panel.
6. Disconnect the parallel wires from the connectors
FW951 on the power trans PCB.
7. Remove the clamp of AC power cord from the chassis.
8. Remove four screws AB that retain the power trans
PCB and then remove the assembly.
from the rear panel. (Fig.3)
YY
that retains the rear panel, and
MX-KA7
Fuse (F952)
1.6A 250V
Power amp and
supply PCB
Rear panel
Fig.29
Fuse (F951)
3.15A 250V
AA
X
Clamp
YY
Fig.30
AB
Chassis
Fig.31
1-17
MX-KA7
Adjustment method
Measurement instruments required
for adjustment
Radio input signal
1. Low frequency oscillator.
This oscillator should have a capacity to output
0dB to 600ohm at an oscillation frequency of
50Hz-20kHz.
2. Attenuator impedance : 600ohm
3. Electronic voltmeter
4. Frequency counter
5. Wow flutter meter
6. Test tape
VT712 : For Tape speed and wow flutter ( 3kHz)
VT703 : For Head angle (10kHz)
7. Blank tape
TAPE I : AC-225 TAPE II : AC-514
8. Torque gauge : For play and back tension forward;
TW2111A, Reverse; TW2121A Fast Forward and
Rewind; TW2231A
9. Test disc: CTS-1000(12cm),GRG-1211(8cm)
10. Jitter meter
Measurement conditions
Power supply voltage
AC 120V (60Hz)
Measurement
output terminal : Speaker out
: TP101(Measuring for TUNER/
DECK/CD)
: Dummy load 6ohm
AM modulation frequency : 400Hz
Modulation factor : 30%
FM modulation frequency : 1kHz
Frequency displacement : 22.5kHz
Frequency Range
AM 530kHz~1710kHz
FM 87.5MHz~108MHz
Standard measurement positions of
volume and switch
Power : Standby (Light STANDBY Indicator)
Sound Turbo, A, BASS EX : OFF
Sound mode : OFF
Main VOL. : 0 Minimum
Travers mecha set position : Disc 1
Precautions for measurement
1. Apply 30pF and 33kohm to the IF sweeper output
side and 0.082 F and 100kohm in series to the
sweeper input side.
2. The IF sweeper output level should be made as
low as possible within the adjustable range.
3. Since the IF sweeper is a fixed device, there is no
need to adjust this sweeper.
4. Since a ceramic oscillator is used, there is no need
to perform any MPX adjustment.
5. Since a fixed coil is used, there is no need to adjust
the FM tracking.
6. The input and output earth systems are separated.
In case of simultaneously measuring the voltage in
both of the input and output systems with an
electronic voltmeter for two channels, therefore, the
earth should be connected particularly.
7. In the case of BTL connection amplifier, the minus
terminal of speaker is not for earthing. Therefore,
be sure not to connect any other earth terminal to
this terminal. This system is of an OTL system.
1-18
Arrangement of adjusting positions
Cassette deck mechanism
(Front side)
MX-KA7
PB Head
k-A)
(Dec
Head azimuth screw
(Forward side)
Head azimuth screw
(Rev
Tape recorder section
Items
Cassette Head
Azimuth Alignments
Measurement
Test tape
: VT703 (10kHz)
Measurement output
terminal
: Left and Right
speaker output
(6-ohm loaded)
or
Headphone Output
(32-ohm loaded)
Head azimuth screw
(Forw
erse side)
conditions
REC/PB Head
(Deck-B)
ard side)
Head azimuth screw
(Reverse side)
Measurement method
1. Playback the test tape VT703 (10KHz) or equivalent.
2. Adjust the head azimuth screw to obtain maximum
output and both output of L / R is in 3dB.
3. Put on the screw lock paint after alignments.
Standard
values
Maximum output
Adjusting
positions
Adjust the
head azimuth
screw only
when the head
has been
changed.
Recording Bias
F
requency Alignment
Tuner section
Items
AM Tracking
Alignments
AM IFT Alignments
Note: The adjustment of CD section is not required.
Test tape
: TYPE I AC-514
Measurement output
terminal
: Erase head terminal
(CN308 8-Pin)
Measurement
conditions
Input signal
: 530kHz
600kHz
Adjustment point
: Antenna coil (L2)
Input signal
: 530kHz
Adjustment point
: IFT (T1)
1. Insert the recording tape in deck-B.
2. Starting the recording.
3. Adjust the oscillation frequency to 80KHz+/-3KHz by
core of Oscillation coil of L301.
1. Set the Signal Generator signal to 530KHz the feed
to Loop Antenna.
2. Receiving the signal and the adjust the OSC coil (L2)
obtain the V.T is 1.40V +/-0.05V.
3. Change the receiving frequency to 600KHz (603KHz).
4. Adjust the Antenna coil ( L2 ) obtain maximum
sensitivity. (Adjust the SSG output to out of AGC range.)
1. Set the receiving frequency to 530KHz.
2. Feed the 450KHz signal to AM antenna input.
3.Adjust the IFT Block T1 obtain to maximum output.
(Adjust the SSG output to out of AGC range.)
Measurement method
80kHz+/-3kHz
Standard
values
V. T
: 1.40V+/-0.05V
Maximum
sensitivity
Maximum output
Use the HighImpedance
Probe or
Frequency
counter input.
Adjusting
positions
Adjust the OSC
coil only when
the AM coil block
has been changed.
Adjust the IFT
only when the
IFT block has
been changed.
1-19
MX-KA7
Flow of functional operation until TOC read
Power ON
Play Key
Slider turns REST
SW ON.
Automatic tuning
of TE offset
Check Point
Confirm that the voltage at the pin5
of CN602 is "H"\"L"\"H".
Tracking error waveform at TOC reading
Approx.3sec
Tracking
servo
off states
Automatic measurement
of TE amplitude and
automatic tuning of
TE balance
VREF
pin 20 of
IC611(TE)
Approx
0.3V
Disc states
to rotate
Tracking
servo
on states
Disc to be
braked to stop
TOC reading
finishes
500mv/div
2ms/div
Fig-1
Laser ON
Detection of disc
Automatic tuning of
Focus offset
Automatic measurement of
Focus S-curve amplitude
Disc is rotated
Focus servo ON
(Tracking servo ON)
Automatic measurement of
Tracking error amplitude
Automatic tuning of
Tracking error balance
Check that the voltage at the
pin40 of IC601 is + 5V?
Confirm that the Focus error
S-cuve signal at the pin32 of
IC601 is approx.2Vp-p
Confirm that the signal from
pin24 IC601 is 0V as a
accelerated pulse during
approx.400ms.
Confirm the waveform of
the Tracking error signal.
at the pin 20 of IC611 (R643)
(See fig-1)
1-20
Automatic tuning of
Focus error balance
Automatic tuning of
Focus error gain
Automatic tuning of
Tracking error gain
TOC reading
Play a disc
Confirm the eys-pattern
at the lead of Pin 5 of IC 611
MX-KA7
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.
1. The level of RF output (EFM output : ampli tude of
eye pattern) will below.
Is the level of
RFOUT under
0.48V 0.1Vp-p?
NO
Replace it.
Replacement of laser pickup
Turn off the power switch and,disconnect the
power cord from the AC OUTLET.
Replace the pickup with a normal one.(Refer
to "Pickup Removal" on the previous page)
Plug the power cord in,and turn the power on.
At this time,check that the laser emits for
about 3seconds and the objective lens moves
up and down.
Note: Do not observe the laser beam directly.
Play a disc.
YES
Check the eye-pattern at
O.K
Finish.
(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 laser diode is almost worn out, and the laser pickup
should be replaced.
If the semi-fixed resistor would be adjusted when the pickup operates normally, the laser pickup may be
damaged due to excessive current.
Pin 5 of IC 611
1-21
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