LG DP372B User manual

PORTABLE DVD
SERVICE MANUAL
MODEL: DP372B
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
MODEL: DP372B
SERVICE MANUAL
P/NO : AFN56903619MARCH , 2008
Website http://biz.lgservice.com
Internal Use Only
Av. Sor Juana lnés de la Cruz No 555
Col. San Lorenzo
Tlalnepantla, Estado de México CP 54033
Tel. [phone] Fax. [phone]
Lada sin costo 01 800 50 481 00

1-1
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
CONTENTS
SECTION 1.........SUMMARY
SECTION 2.........EXPLODED VIEWS
SECTION 3.........ELECTRICAL
SECTION 4.........REPLACEMENT PARTS LIST

1-2 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SECTION 1
SUMMARY
CONTENTS
PRODUCT SAFETY SERVICING GUIDELINES FOR PORTABLE DVD PRODUCTS.........1-3
SERVICING PRECAUTIONS....................................................................................................................1-4
• GENERAL SERVICING PRECAUTIONS
• INSULATION CHECKING PRODEDURE
• ELECTROSTATICALLY SENSITIVE (ES) DEVICES
SPECIFICATIONS ........................................................................................................................................1-5

1-3
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
PRODUCT SAFETY SERVICING GUIDELINES FOR PORTABLE DVD PRODUCTS
IMPORTANT SAFETY NOTICE
This manual was prepared for use only by properly trained audio-video service tech-
nicians.
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, imple-
mentation of the latest safety and performance improvement changes into the set are
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 lit-
erature.
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 equilater-
al triangle is intended to convey to the service personnel the following
fuse replacement caution notice:
CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF
FIRE, REPLACE ALL FUSES WITH THE SAME TYPE AND RAT-
ING 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 com-
ponent 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 orig-
inal 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 splash-
es, 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 nec-
essary.
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, han-
dle and screws) to be sure that set is safe to operate without danger of electrical
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 constitutes a poten-
tial 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 ventila-
tion.
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 plat-
form 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 installations.
5. Caution customers against mounting a product on a sloping shelf or in a tilted posi-
tion, 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.

1-4 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SERVICING PRECAUTIONS
CAUTION: Before servicing the PORTABLE DVD covered by
this service data and its supplements and addends, read and
follow the SAFETY PRECAUTIONS. NOTE: if unforeseen cir-
cumstances create conflict between the following servicing
precautions and any of the safety precautions in this publica-
tion, always follow the safety precautions.
Remember Safety First :
General Servicing Precautions
1. Always unplug the PORTABLE DVD 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 electrolyt-
ic 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 PORTABLE DVD 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
which instruments covered by this service manual might be
equipped.
5. Do not apply AC power to this PORTABLE DVD and / or any
of its electrical assemblies unless all solid state device heat
sinks are correctly installed.
6. Always connect the test instrument ground lead to an appro-
priate 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 resistance
between each blade of the attachment plug and accessible
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 component
or semiconductor-equipped assembly, drain off any electro-
static charge on your body by touching a known earth
ground. Alternatively, obtain and wear a commercially avail-
able 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.)

1-5
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SPECIFICATIONS
• DVD PLAYER
Power requirements DC 12V
Power consumption 12W
External dimensions 207 x 39 x 168mm (W x H x D)
Net weight (Approx.) 0.85kg
Operating temperature 5°C to 40°C
Operating humidity 5% to 90%
Laser semiconductor laser
Signal system NTSC
• CONNECTORS
Audio/Video Output ø3.5mm mini jack x 1
- Video: 1.0V(p-p), 75Ω, sync negative
- Audio: 1.5Vrms (1kHz, 0dB)
Earphone terminal ø3.5mm stereo mini jack x 2
• LIQUID CRYSTAL DISPLAY
Panel size 7inches wide (diagonal)
Projection system R.G.B. stripe
Driving system TFT active matrix
Resolution 480 x 234 (WQVGA)
• SUPPLIED ACCESSORIES
RCA Video/Audio cable
AC Adapter (MPA-630)
Automotive Adapter (DPDC1)
Remote Control
Battery for Remote Control (Lithium Battery)

1-6 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
MEMO

2-1
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SECTION 2
EXPLODED VIEWS
CONTENTS
EXPLODED VIEWS .....................................................................................................................................2-2
1. CABINET AND MAIN FRAME SECTION ..................................................................................................2-2
2. PACKING ACCESSORY SECTION...........................................................................................................2-3

2-2 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
D
C
G
H
I
A
E
FG
L
M
C
A
F
E
D
K
J
B
B
A48 A53
A00
A46
A44
A40
A52 A45
A51
A43
A41
277
288
265
264
295
293
296
289
263
262
809
285 285
284
269
261
260
266
283
L
K
H
I
J
M
279
278
CABLE10
CABLE9
CABLE8
CABLE1
282
281
288
286
287
252
272
277 253
LCD
BOARD
INVERTER
BOARD
KEY
BOARD
MAIN
BOARD
CABLE2 CABLE3
262
266
251
251A
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION

2-3
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
2. PACKING ACCESSORY SECTION
PLUG ASS'Y(RCA CABLE)
806
BATTERY
808
834
ADAPTER
833
REMOTE CONTROL
900
MASTER BOX
802
BOX
802B
BOX
802A
801 OWNER'S MANUAL
CABLE, CIGAR JACK
804 PACKING SHEET
803 BAG
835 CAR-MOUNT

2-4 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
MEMO

3-1
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SECTION 3
ELECTRICAL
CONTENTS
ELECTRICAL TROUBLESHOOTING GUIDE ...................................................................................3-2
1. POWER CHECK FLOW.........................................................................................................................3-2
2. SYSTEM OPERATION FLOW ...............................................................................................................3-3
3. SYSTEM TEST FLOW ..........................................................................................................................3-4
DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING .................................3-10
1. SYSTEM 27MHZ CLOCK, RESET, FLASH SCK SIGNAL. .................................................................3-10
2. SDRAM CLOCK ...................................................................................................................................3-12
3. TRAY OPEN/CLOSE SIGNAL..............................................................................................................3-12
4. SLED CONTROL RELATED SIGNAL..................................................................................................3-13
5. LASER POWER CONTROL RELATED SIGNAL.................................................................................3-14
6. SPINDLE CONTROL WAVEFORM......................................................................................................3-14
7. FOCUS ON WAVEFORM.....................................................................................................................3-15
8. TRACKING CONTROL RELATED SIGNAL(System checking) ...........................................................3-16
9. 1389DE/LP VIDEO OUTPUT WAVEFORM .........................................................................................3-17
10. AUDIO OUTPUT FROM 1389DE/LP .................................................................................................3-17
WIRING CONNECTION DIAGRAMS..................................................................................................3-18
1. WIRING CONNECTION DIAGRAM-1..................................................................................................3-18
2. WIRING CONNECTION DIAGRAM-2..................................................................................................3-19
BLOCK DIAGRAMS.................................................................................................................................3-20
1. OVERALL BLOCK DIAGRAM..............................................................................................................3-20
2. POWER BLOCK DIAGRAM.................................................................................................................3-21
3. SERVO BLOCK DIAGRAM..................................................................................................................3-22
4. SYSTEM BLOCK DIAGRAM................................................................................................................3-23
5. AV BLOCK DIAGRAM ..........................................................................................................................3-24
6. LCD BLOCK DIAGRAM .......................................................................................................................3-25
CIRCUIT DIAGRAMS ..............................................................................................................................3-27
1. MPEG CIRCUIT DIAGRAM .................................................................................................................3-27
2. MEMORY CIRCUIT DIAGRAM ............................................................................................................3-29
3. OPU & MOTOR CIRCUIT DIAGRAM ..................................................................................................3-31
4. AV CIRCUIT DIAGRAM........................................................................................................................3-33
5. CHARGE CIRCUIT DIAGRAM.............................................................................................................3-35
6. LCD IF CIRCUIT DIAGRAM.................................................................................................................3-37
7. AUDIO CIRCUIT DIAGRAM.................................................................................................................3-39
8. KEY CIRCUIT DIAGRAM .....................................................................................................................3-41
9. LCD KEY CIRCUIT DIAGRAM.............................................................................................................3-43
CIRCUIT VOLTAGE CHART ..........................................................................................................3-45
PRINTED CIRCUIT BOARD DIAGRAMS .........................................................................................3-49
1. MAIN P.C.BOARD ................................................................................................................................3-49
2. LCD P.C.BOARD ..................................................................................................................................3-53
3. INVERTER P.C.BOARD .......................................................................................................................3-53
4. KEY P.C.BOARD ..................................................................................................................................3-53

3-2
ELECTRICAL TROUBLESHOOTING GUIDE
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
No 3.3VA
Check Q402/Q415
and Replace Replace U401
NO
1. POWER CHECK FLOW
A. B.
Is
5VA section
working?
Check Q408/D401
and Replace
Check Q410/D402
and Replace
YES
YES
YESNO
Is
VCC_5V section
working?
No 5VA
Check D606
Replace
NO
BAT_OUT=12V?
YES
YES

3-3
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
Power on
1. 8032 initializes SERVO,DSP & RISC registers
2. Write RISC code to SDRAM
3. Reset RISC
Show LOGO
Tray close to closed position
SLED moves to inner position
1. Judge whether have disc and disc type
2. Jump to related disc reading procedure
1. Execute pressed Key & IR key
2. System operation routine loop
1. Stop playback & open Tray
2. Display tray open message & LOGO
NO
YES
YES
NO
YES
YES
NO
NO
2. SYSTEM OPERATION FLOW
Tray closed?
SLED at
inner side?
Receive
OPEN/CLOSE Key?
Receive
CLOSE Key?

3-4 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. SYSTEM TEST FLOW
TEST
Replace power PCBA or AC transformer.
YES
NO
Switch on the power PCBA
Repair or Replace power PCBA
YES
NO
Make sure the main PCBA don't
short on VCCs and switch it on.
YES
Check the regulators or related diodes.
YES
NO
Connect to PC RS232 cable and
update the FLASH memory code.
1. Check 27MHz system clock.
2. Check system reset circuit.
3. Check FLASH R/W enable signal PRD,
RWR.
4. Check RS232 SIGNALS.
5. Check FLASH Memory related circuit.
NO
A
YES
Check the
AC voltage power PCBA
(110V or 220V)
Update FLASH
successfully?
Is the DC voltage
outputs OK? (5V, 3.3V, 12V,
5.6V MOTOR)
Is 3.3V and 1.8V DC
outputs normal on main
PCBA?

3-5
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
RESET or power on.
NO NO
YES
Check connection lines between
FLASH & MTK1389DE/LP and
the FLASH access time whether
is suitable or not.
NO
YES
Check connection lines
between SDRAM &
MTK1389DE/LP and the
SDRAM is damaged.
NO
YES
Check the related circuit
of1389DE/LP.
NO
YES
Check the filtering and
amp circuit of TV signal.
Check AV cable
connection to TV set.
NO NO
YES
Check the load
OPEN & CLOSE switch
NO
YES
Check the Tray control IO pins
on 1389DE/LP & AM5898N.
NO
YES
Check the Tray control
amplifying circuit on Motor driver.
Check the cable connection
between main PCBA and loader.
YES
YES
Show LOGO?
Flash
memory operates
properly?
138PDE/LP
VIDEO outputs
properly?
Normal
OPEN_SW & CLOSE_SW
signals?
Normal
OPEN & CLOSE
signal?
Normal
FAN_TRAY+ & FAN_TRAY-
signal?
Does tray
move inside when
it is not at closed
position?
SDRAM
works properly?
Have TV
signal output?
A
B

3-6 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
NONO
YES
Check the connection line of
DR_MUTE signal.
NO
YES
Check the related
circuit of SLD_PWM
NO
YES
Check the amp
circuit on motor driver.
Check the cable
connection with MECHA.
Do not put in disc and
tray close.
YES
YES
Check cable connect on
with pick-up head.
YES
YES
Motor
driver DR_MUTE
pin is high?
Is SLD_PWM
DC level higher
than 1.65V?
FAN_SLD+ &
FAN_SLD- output
properly?
Does the
SLED move to inner
side when it is at
outer position?
NONO Check FOD connection on
1389DE/LP and motor driver.
Proper
FOD outputs to motor
driver?
NO Check the amp circuit
on motor driver.
Proper
FCS+ & FCS
outputs?
Optical
lens has movements
for searching
focus?
B
C

3-7
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
NO NO
YES
YES
Check the laser power circuit
on 1389DE/LP and connecting
to power transistor.
Check cable connection
between transistor output
and pick-up head
NO Laser off
NO NO
YES
Check the related circuit
on RF signal.
Check
DVD_LD & CD_LD signal
YES
YES
NO NO
YES
Check SPD_PWM related
circuit on 1389DE/LP.
YES
Check the cable connection
between spindle and main PCBA.
YES
YES
Laser
turns on when
reading disc?
DVD_LD,
CD_LD output
properly?
NO Check the related circuit on
laser power transistor
Collector
voltage of power transistor
is OK?
Put disc in?
Disc ID
is correct?
Does
spindle rotate?
Proper
SPD_PWM signal on
1389DE/LP
NO Check the spindle control
amp circuit of motor driver
FAN_SPN+
& FAN_SPN output
properly?
Proper RF
signal on OPU
C
D

3-8 Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
NO NO
YES
YES
Check connections between
1389DE/LP and pick-up head.
Check cable connection
on pick-up head.
NO
YES
YES
YES
YES
YES
Check cable connection
on pick-up head.
Check RF signal waveform.
Focus
on OK?
Proper
signals on A,B,C,D of
1389DE/LP
NO NO Check the TRD
connection on 1389DE/LP
and motor driver
Track
on OK?
Disc is play?
Properly
TRD signal on
1389DE/LP?
NO Check the tracking control
amp circuit on motor driver
TRK+ & TRK-
output properly?
NO Check the FOD connection on
1389DE/LP and motor driver.
Check
FOD signal on
1389DE/LP
YES
Check the focus control
amp circuit on motor driver
FCS+ & FCS-
output properly?
D
E

3-9
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
NO NO
YES
YES
Check connection between
1389DE/LP & audio AMP.
Check audio filter,
amplify, mute circuit.
NO NO
YES
Check communication
lines on 1389DE/LP.
YES
YES
TEST END Check the cable
connection on front panel.
Normal
audio output when
disc playback?
Audio
AMP received correct
data stream?
Commu-
nications between
IR.VFD front panel key &
1389DE/LP is
normally?
Normal
IR.VFD & Front panel
key functions?
NO Check the related
circuit of audio AMP.
Normal
audio AMP
out?
E