LG XA64 Series User manual

MICRO Hi-Fi SYSTEM
SERVICE MANUAL
MODEL: XA64 (XAS64F)
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
MODEL: XA64 (XAS64F)SERVICE MANUAL
9002,NOVEMBER97405237NFA:ON/P
Website http://biz.lgservice.com
Internal Use Only

CONTENTS
SECTION 1 ........SUMMARY
SECTION 2 ........CABINET & MAIN CHASSIS
SECTION 3 ........ELECTRICAL
SECTION 4 ........REPLACEMENT PARTS LIST
1-1

SECTION 1
SUMMARY
CONTENTS
PRODUCT SAFETY SERVICING GUIDELINES FOR A/V PRODUCTS................................... 1-3
SERVICING PRECAUTIONS................................................................................................................... 1-4
• GENERAL SERVICING PRECAUTIONS
• INSULATION CHECKING PRODEDURE
• ELECTROSTATICALLY SENSITIVE (ES) DEVICES
SERVICE INFORMATION FOR EEPROM.......................................................................................... 1-5
PROGRAM UPDATE GUIDE................................................................................................................... 1-6
SPECIFICATIONS....................................................................................................................................... 1-7
1-2

PRODUCT SAFETY SERVICING GUIDELINES
FOR A/V PRODUCTS
IMPORTANT SAFETY NOTICE
This manual was prepared for use only by properly trained audio-video service
technicians.
When servicing this product, under no circumstances should the original design be
modified or altered without permission from LG Corporation. All components should
be replaced only with types identical to those in the original circuit and their physical
location, wiring and lead dress must conform to original layout upon completion of
repairs.
Special components are also used to prevent x-radiation, shock and fire hazard.
These components are indicated by the letter “x” included in their component desig-
nators and are required to maintain safe performance. No deviations are allowed
without prior approval by LG Corporation.
Circuit diagrams may occasionally differ from the actual circuit used. This way,
implementation of the latest safety and performance improvement changes into the
set is not delayed until the new service literature is printed.
CAUTION : Do not attempt to modify this product in any way. Never perform cus-
tomized installations without manufacturer’s approval. Unauthorized modifications
will not only void the warranty, but may lead to property damage or user injury.
Service work should be performed only after you are thoroughly familiar with these
safety checks and servicing guidelines.
GRAPHIC SYMBOLS
The exclamation point within an equilateral triangle is intended to alert
the service personnel to important safety information in the service
literature.
The lightning flash with arrowhead symbol within an equilateral trian-
gle is intended to alert the service personnel to the presence of non-
insulated “dangerous voltage” that may be of sufficient magnitude to
constitute a risk of electric shock.
The pictorial representation of a fuse and its rating within an equilat-
eral triangle is intended to convey to the service personnel the follow-
ing fuse replacement caution notice:
CAUTION : FOR CONTINUED PROTECTION AGAINST RISK OF
FIRE, REPLACE ALL FUSES WITH THE SAME TYPE AND
RATING AS MARKED NEAR EACH FUSE.
SERVICE INFORMATION
While servicing, use an isolation transformer for protection from AC line shock. After
the original service problem has been corrected, make a check of the following:
FIRE AND SHOCK HAZARD
1. Be sure that all components are positioned to avoid a possibility of adjacent
component shorts. This is especially important on items trans-ported to and from
the repair shop.
2. Verify that all protective devices such as insulators, barriers, covers, shields, strain
reliefs, power supply cords, and other hardware have been reinstalled per the
original design. Be sure that the safety purpose of the polarized line plug has not
been defeated.
3. Soldering must be inspected to discover possible cold solder joints, solder
splashes, or sharp solder points. Be certain to remove all loose foreign particles.
4. Check for physical evidence of damage or deterioration to parts and components,
for frayed leads or damaged insulation (including the AC cord), and replace if
necessary.
5. No lead or component should touch a high current device or a resistor rated at 1
watt or more. Lead tension around protruding metal surfaces must be avoided.
6. After reassembly of the set, always perform an AC leakage test on all exposed
metallic parts of the cabinet (the channel selector knobs, antenna terminals,
handle and screws) to be sure that set is safe to operate without danger of electri-
cal shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS
TEST. Use an AC voltmeter having 5000 ohms per volt or more sensitivity in the
following manner: Connect a 1500 ohm, 10 watt resistor, paralleled by a .15 mfd
150V AC type capacitor between a known good earth ground water pipe, conduit,
etc.) and the exposed metallic parts, one at a time. Measure the AC voltage
across the combination of 1500 ohm resistor and .15 mfd capacitor. Reverse the
AC plug by using a non-polarized adaptor and repeat AC voltage measurements
for each exposed metallic part. Voltage measured must not exceed 0.75 volts
RMS. This corresponds to 0.5 milliamp AC. Any value exceeding this limit consti-
tutes a potential shock hazard and must be corrected immediately.
TIPS ON PROPER INSTALLATION
1. Never install any receiver in a closed-in recess, cubbyhole, or closely fitting shelf
space over, or close to, a heat duct, or in the path of heated air flow.
2. Avoid conditions of high humidity such as: outdoor patio installations where dew
is a factor, near steam radiators where steam leakage is a factor, etc.
3. Avoid placement where draperies may obstruct venting. The customer should
also avoid the use of decorative scarves or other coverings that might obstruct
ventilation.
4. Wall- and shelf-mounted installations using a commercial mounting kit must follow
the factory-approved mounting instructions. A product mounted to a shelf or
platform must retain its original feet (or the equivalent thickness in spacers) to
provide adequate air flow across the bottom. Bolts or screws used for fasteners
must not touch any parts or wiring. Perform leakage tests on customized installa-
tions.
5. Caution customers against mounting a product on a sloping shelf or in a tilted
position, unless the receiver is properly secured.
6. A product on a roll-about cart should be stable in its mounting to the cart.
Caution the customer on the hazards of trying to roll a cart with small casters
across thresholds or deep pile carpets.
7. Caution customers against using extension cords. Explain that a forest of exten-
sions, sprouting from a single outlet, can lead to disastrous consequences to
home and family.
1-3

SERVICING PRECAUTIONS
CAUTION: Before servicing the A/V products covered by this
service data and its supplements and addends, read and fol-
low the SAFETY PRECAUTIONS.
NOTE: if unforeseen circumstances create conflict between
the following servicing precautions and any of the safety pre-
cautions in this publications, always follow the safety precau-
tions.
Remember Safety First :
General Servicing Precautions
1.Always unplug the A/V products AC power cord from the
AC power source before:
(1) Removing or reinstalling any component, circuit board,
module, or any other assembly.
(2) Disconnecting or reconnecting any internal electrical
plug or other electrical connection.
(3) Connecting a test substitute in parallel with an electro-
lytic capacitor.
Caution : A wrong part substitution or incorrect polarity
installation of electrolytic capacitors may result in an
explosion hazard.
2.Do not spray chemicals on or near this A/V product or any
of its assemblies.
3.Unless specified otherwise in this service data, clean elec-
trical contacts by applying an appropriate contact cleaning
solution to the contacts with a pipe cleaner, cotton-tipped
swab, or comparable soft applicator.
Unless specified otherwise in this service data, lubrication
of contacts is not required.
4.Do not defeat any plug/socket B+ voltage interlocks with
whitch instruments covered by this service manual might be
equipped.
5.Do not apply AC power to this A/V product and / or any of
its electrical assemblies unless all solidstate device heat
sinks are correctly installed.
6.Always connect the test instrument ground lead to an
appropriate ground before connecting the test instrument
positive lead. Always remove the test instrument ground
lead last.
Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet and turn
the power on. Connect an insulation resistance meter (500V)
to the blades of the attachment plug. The insulation resist-
ance between each blade of the attachment plug and acces-
sible conductive parts (Note 1) should be more than 1Mohm.
Note 1 : Accessible Conductive Parts include Metal panels,
Input terminals, Earphone jacks,etc.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of
typical ES devices are integrated circuits and some field effect
transistors and semiconductor chip components.
The following techniques should be used to help reduce the
incidence of component damage caused by static electricity.
1.Immediately before handling any semiconductor compo-
nent or semiconductor-equipped assembly, drain off any
electrostatic charge on your body by touching a known
earth ground. Alternatively, obtain and wear a commercially
available discharging wrist strap device, which should be
removed for potential shock reasons prior to applying
power to the unit under test.
2.After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such
as aluminum foil, to prevent electrostatic charge buildup or
exposure of the assembly.
3.Use only a grounded-tip soldering iron to solder or unsolder
ES devices.
4.Use only an anti-static solder removal device. Some solder
removal devices not classified as “anti-static” can generate
electrical charges sufficient to damage ES devices.
5.Do not use freon-propelled chemicals. These can generate
an electrical charge sufficient to damage ES devices.
6.Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum
foil,or comparable conductive material).
7.Immediately before removing the protective material from
the leads of a replacement ES device, touch the protective
material to the chassis or circuit assembly into which the
device will be installed.
Caution: Be sure no power is applied to the chassis or cir-
cuit, and observe all other safety precautions.
8.Minimize bodily motions when handling unpackaged
replacement ES devices. (Normally harmless motion such
as the brushing together of your clothes fabric or the lifting
of your foot from a carpeted floor can generate static elec-
tricity sufficient to damage an ES device.)
1-4

SERVICE INFORMATION FOR EEPROM
POWER ON
Completed
FLD ‘OP0-xx….
Press ‘STOP’ key.
Press ‘POWER’ key once.
FLD ‘write ok’
Move to appropriate position and
make changes with remote control
‘REPEAT / PLAY / BWD SKIP /
FWD SKIP’.
FLD no disc status
Front ‘STOP’ + Remote control ‘FWD
SKIP’ push same timing during 5s. DETECT NEW EEPROM
(OPTION EDIT SCREEN)
NAME HEX
OP0 xx
OP1 xx
OP2 xx
. .
. .
. .
1-5

PROGRAM UPDATE GUIDE
1-6
1. HOW TO UPDATE ESS PROGRAM
(1) Rename the file name to download as “LG_(MODEL NAME)_(Vresion).ROM” in upper cases.
ex) XA64 : “LG_XA64_0905180.ROM”
Refer to the Standard for naming of software.
(2) Copy the file to the formatted USB, and burn it.
(3) Move to the USB function, and insert the USB to the set.
The upgrade information will be shown on the screen.
(4) Remove the USB.
(5) Remove and reconnect the power cable when it changes to logo screen from upgrade information.
Then the upgrade process is completed.
2. HOW TO UPDATE SANYO PROGRAM
(1) Change the file name to download as “(MODEL NAME)_(Version).HEX”. in upper cases
ex) XA64: XA64_0809262.HEX
(2) Copy the file to the root folder of USB storage.
(3) Put the USB into the set.
Then the upgrade process will be started with the upgrade information.
(4) If the upgrade process is complete, the set will be rebooted with “Complete” message.
3. HOW TO UPDATE MCS PROGRAM
(1) Change the file name to download as “(MODEL NAME)_(Option)_(Version).MCS”.
ex) XA64_01010_07.HEX
(2) Copy the file to the root folder of USB storage.
(3) Put the USB into the set.
Then the upgrade process will be started with the upgrade information.
(4) If the upgrade process is complete, the set will be rebooted with “SUCCESS” message.

SPECIFICATIONS
• GENERAL
Power supply 200 ~ 240 V, 50/60 Hz
Power consumption 50 W
Net Weight 2.71 kg
External dimensions (W x H x D) 170 x 240 x 253 (mm)
Operating temperature 5°C ~ 35°C
Operating humidity 5 % ~ 85 %
• TUNER
FM Tuning Range 87.5 ~ 108.0 MHz
AM Tuning Range 522 ~ 1,620 KHz
• AMPLIFIER
Output Power 30 W + 30 W
T.H.D 0.5 %
Frequency Response 50 Hz ~ 20 KHz
Signal-to-noise ratio 70 dB
• CD
Frequency response 100 Hz ~ 18 KHz
Signal-to-noise ratio 70 dB
Dynamic range 55 dB
• SPEAKERS
Type 2 Way 2 Speaker
impedance 6 Ω
Rated Input Power 30 W
Max. Input Power 60 W
Net Dimensions (W x H x D) 150 x 243 x 180 (mm)
Net Weight 2.08 kg
Note : Design and specifications are subject to change prior notice.
1-7

SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
EXPLODED VIEWS..................................................................................................................................... 2-3
1. CABINET AND MAIN FRAME SECTION ................................................................................................. 2-3
2. SPEAKER SECTION ................................................................................................................................ 2-7
3. PACKING ACCESSORY SECTION ......................................................................................................... 2-8
2-1

2-3 2-4
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION
265
266
B
L
D
A
C
I
G
FH
G
H
F
C
K
D
IE
K
J
E
B
A
J
L
261
260
453
453
453
453
451
451
452
453
452
453
451
453
452
452
455
452
A26
258
A43
A41
257
255R
255L
259L 259R
A42
266
A47
454
454
262
263
CABLE1
CABLE2
CABLE3
A45
264
268
267
300
266
254
250
252
251
252
253
256
MAIN
MCU
SMPS
USB
DISPLAY
KEY

2-7
2. SPEAKER SECTION
A60L
A60R

2-8
3. PACKING ACCESSORY SECTION
Battery808
Remote controller900
Instruction Ass'y801
Packing803
Box802
Bag804

SECTION 3
ELECTRICAL
CONTENTS
ELECTRICAL TROUBLESHOOTING GUIDE.................................................................................... 3-2
1. SMPS PART........................................................................................................................................... 3-2
2. MUTE...................................................................................................................................................... 3-3
3. AUDIO ABNORMAL............................................................................................................................... 3-4
4. AUDIO FUNCTION MODE..................................................................................................................... 3-5
5. IC301 TROUBLESHOOTING................................................................................................................. 3-6
6. IC600 TROUBLESHOOTING................................................................................................................. 3-7
7. IC601 TROUBLESHOOTING................................................................................................................. 3-8
8. IC603 TROUBLESHOOTING................................................................................................................. 3-8
9. U503 TROUBLESHOOTING.................................................................................................................. 3-9
10. TU501 FM TUNER MODULE................................................................................................................. 3-9
11. CD PART.............................................................................................................................................. 3-10
12. CD READING CHECK.......................................................................................................................... 3-11
13. USB PART............................................................................................................................................ 3-12
WAVEFORMS............................................................................................................................................. 3-13
1. CD SEARCHING WAVEFORM............................................................................................................ 3-13
2. SPINDLE DRIVE & MOTOR WAVEFORM.......................................................................................... 3-13
3. CD PLAYING WAVEFORM.................................................................................................................. 3-14
4. CD STOP ACTION WAVEFORM......................................................................................................... 3-15
5. CD READING WAVEFORM................................................................................................................. 3-15
6. CD PLAYING RF WAVEFORM............................................................................................................ 3-16
7. USB OPERATING WAVEFORM.......................................................................................................... 3-17
8. RADIO OPERATING WAVEFORM...................................................................................................... 3-17
WIRING DIAGRAM................................................................................................................................... 3-19
BLOCK DIAGRAMS................................................................................................................................. 3-21
CIRCUIT DIAGRAMS...............................................................................................................................3-23
1. SMPS CIRCUIT DIAGRAM.................................................................................................................. 3-23
2. MAIN CIRCUIT DIAGRAM ................................................................................................................... 3-25
3. MAIN - CD CIRCUIT DIAGRAM........................................................................................................... 3-27
4. MCU CIRCUIT DIAGRAM.................................................................................................................... 3-29
5. FRONT, USB & HEADPHONE CIRCUIT DIAGRAM........................................................................... 3-31
CIRCUIT VOLTAGE CHART.................................................................................................................3-33
PRINTED CIRCUIT BOARD DIAGRAMS ......................................................................................... 3-35
1. MAIN P.C.BOARD................................................................................................................................ 3-35
2. SMPS P.C.BOARD............................................................................................................................... 3-37
3. MCU P.C.BOARD................................................................................................................................. 3-37
4. KEY P.C.BOARD.................................................................................................................................. 3-39
5. FRONT P.C.BOARD............................................................................................................................. 3-39
3-1

1. SMPS PART
5.0V
Replace F901 (Use same type fuse)
Replace D914
Replace RT901
Replace R904
Check or replace D906, R907
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
Is F901 nomal?
Is D914 nomal?
Is RT901 nomal?
Is
VSTR(130V-310V) supplied to
IC901 pin5?
Replace BD901
Replace IC903, PC903
Is D906, R907 nomal?
NO
NO
NO
NO
Is BD901 nomal?
Is IC903, PC903 nomal?
Is
Vcc(9V-25V) supplied to
IC901 pin2?
Power line of main PCB is short
3-2
ELECTRICAL TROUBLESHOOTING GUIDE

2. MUTE
YES
YES
NO
YES
Mute
Replace Q704, Q705
Check U600 pin17
Check R622
Check IC603 pin69
Replace R622
NO
NO
NO
NO
Check "Low"
of Q704, Q705 "C"
Does "High" appear
at Q704, Q705 "B"?
Mute
3-3
ELECTRICAL TROUBLESHOOTING GUIDE

3. AUDIO ABNORMAL
Audio abnormal
Check the speakers connection
Check the function input
YES
YES
YES
YES
YES
NO
NO
Check the output
U702 pin2, 4, 8,10
Check the DC 9.5V
of U503 pin24
Check the "High" of U702 pin5
Check ZD703, D705
NO
NO
Check the input signal
of U702 pin7, 11
Check the DC 12V
of R701
Check the power circuit
3-4
ELECTRICAL TROUBLESHOOTING GUIDE

4. AUDIO FUNCTION MODE
Portable
Tuner
CD / USB
Check the input signal of CON541
Check the output signal of TU101 pin1, 2
Check the output signal of U502 pin55, 57
and refer to CD trobleshooting
Check the output signal of U503 pin19, 23
Check the output signal of U503 pin19, 23
Check the output signal of U503 pin19, 23
YES
YES
YES
NO
NO
NO
Check the input signal
of U503 pin7, 8
Check the input signal
of U503 pin1, 2
Check the input signal
of U503 pin3, 4
3-5
ELECTRICAL TROUBLESHOOTING GUIDE

5. IC301 TROUBLESHOOTING
VFD display check
Refer to power troubleshooting
Check or replace R302
Check IC603 pin91 STB, pin57 Data, pin56 CS
YES
YES
NO
YES
NO
NO
Check the power supply
to IC301 pin9, 50, 51
Check IC301 pin7 FOSC
Check CON301 pin7 STB, pin8 Data, pin9 CS
NO
NO
Check
IC301 pin1 CS, pin3 STB
pin2, 4 Data
OK
3-6
ELECTRICAL TROUBLESHOOTING GUIDE

6. IC600 TROUBLESHOOTING
IC600 troubleshooting
Refer to power supply no 3.3V
or check and replace Q600
Check or replace L600
YES
YES
YES
YES
NO
NO
Check
both end voltage
Q600 (3.3V)
Check
IC604 pin13 is 3.3V
Check IC603 pin5 is "H",
check and replace Q601
Check or replace X601
NO
NO
Check Q601 is "H"
Check
IC600 pin1, 6 and X601
operation
OK
3-7
ELECTRICAL TROUBLESHOOTING GUIDE

7. IC601 TROUBLESHOOTING
8. IC603 TROUBLESHOOTING
NO
NO
YES
IC601 troubleshooting
Refer to
MCU troubleshooting
Replace MCU
NO
YES
YES
Check
IC601 pin34: CLK,
pin35: CKE
Check
MCU IC603 voltage
1.2V
Check MCU IC603
OK
IC603 troubleshooting
Refer both end voltage
of IC501, IC605 3.3V/1.2V
Check or replace X600
YES
YES
YES
YES
NO
NO
Check
both end voltage of IC605
(1.2V/3.3V)
Check
IC603 pin111, 112, X600
operation
Check or replace R601
Check IC602 reset circuit
NO
NO
Check IC603
pin13, 47, 94, 120, 122, 124 voltage
1.2V are in
When
power supply to IC603 pin107
(Low-->High)
OK
3-8
ELECTRICAL TROUBLESHOOTING GUIDE