LG RH265 User manual

HDD/DVD RECORDER
SERVICE MANUAL
MODEL: RH265/RH266
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
MODEL: RH265/RH266
SERVICE MANUAL
P/NO : AFN35914202 SEP, 2007
Website http://biz.lgservice.com
Internal Use Only

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
CONTENTS
SECTION 1.........SUMMARY
SECTION 2.........CABINET & MAIN CHASSIS
SECTION 3.........ELECTRICAL
SECTION 4.........REPLACEMENT PARTS LIST

1-2 Copyright © 2007 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
HDD/DVD RECORDER PRODUCTS .....................................................................................................1-3
SERVICING PRECAUTIONS....................................................................................................................1-4
• GENERAL SERVICING PRECAUTIONS
• INSULATION CHECKING PRODEDURE
• ELECTROSTATICALLY SENSITIVE (ES) DEVICES
MV3 AUTOMATIC LIGHT ADJUSTMENT PROCESS .....................................................................1-5
SERVICE INFORMATION FOR EEPROM IC SETTING..................................................................1-6
UPGRADE THE MAIN & LOADER PROGRAM.................................................................................1-7
SPECIFICATIONS ........................................................................................................................................1-8

1-3
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
PRODUCT SAFETY SERVICING GUIDELINES FOR
HDD/DVD RECORDER 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
designators 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 are not delayed until the new service literature is printed.
CAUTION : Do not attempt to modify this product in any way. Never perform
customized 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 triangle
is intended to alert the service personnel to the presence of
noninsulated “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 equilateral
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 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 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
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
installations.
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
extensions, sprouting from a single outlet, can lead to disastrous consequences to
home and family.

1-4 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SERVICING PRECAUTIONS
CAUTION: Before servicing the DVD RECORDER covered by
this service data and its supplements and addends, read and
follow the SAFETY PRECAUTIONS. NOTE: if unforeseen
circumstances create conflict between the following servicing
precautions and any of the safety precautions in this
publication, always follow the safety precautions.
Remember Safety First:
General Servicing Precautions
1. Always unplug the DVD RECORDER 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
electrolytic 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 DVD RECORDER or
any of its assemblies.
3. Unless specified otherwise in this service data, clean
electrical 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 DVD RECORDER 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
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 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
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
circuit, 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
electricity sufficient to damage an ES device.)

1-5
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
MV3 AUTOMATIC LIGHT ADJUSTMENT PROCESS
1. DEFAULT SETTING ROUTINE FOR THE RECORDING POWER
- Firstly the default setting process for the recording power is required to manufacture in a set.
- MV3 Loader Program includes the routine for performing the recording power setting and after assembling
in the production line, this should be activated to adjust the recording difference of each set before the
recording test.
- On next page, the description follows for a method to operate this routine by special combination of the keys
of the remote control on the setup menu screen.
2. WRITE POWER INITIALIZATION REQUEST
The procedure of Write Power Initialization Request :
1) Move to the lock from the Setup menu.
2) When BE detects the special pattern (5-7-2-0) entered by the remote control input, GUI appears as Fig. 1.
3) If you select YES, BE sends ATAPI vender specific Command (F6) below to FE and shows Fig. 2.
If you select NO, it normally comes to an end.
4) Wait until the Command from FE is completed. It takes about 15 seconds.
5) After the Command is completed, the screen shows OK/NG screen.
In case of normal completion of the Command, OK screen appears (Fig. 3).
In case of abnormal completion of the Command, NG screen appears (Fig. 4).
6) If you select YES, GUI disappears and normal operation begins.
NOTE : Power setting should be performed without Disc.
Fig. 1 Fig. 2
Fig. 3 Fig. 4

1-6 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SERVICE INFORMATION FOR EEPROM IC SETTING
1. Press the CLEAR button on the remote control together with OPEN the Front Panel about 6 seconds.
The picture on OSD will be bellow :
2. To MOVE from OP! to another option, Please button on the remote control.
3. To CHANGE the option code, Please button on the remote control.
4. To APPLY the option code, after change the option press ENTER button on remote control.
5. To INITIALIZE the system, press CLEAR button on the remote control together with OPEN on the front panel
about 2 seconds.
7. To exit from the option code menu without initializing the system, just turn off the power and then turn on
again.
MODEL : RH265/RH266 Disc Read Time
DVD 018 Sec OK
CD 021 Sec NG
OP1 : 00 00000000 M : 10, D13
OP2 : 00 00000000 E: FF (OR)
OP3 : 00 00000000
OP4 :00 00000000
OP5 : 00 00000000
OP6 : 00 00000000
OP7 : 00 00000000 Write:OK
OP8 : 00 00000000 EXIT:MP
OP9 : 00 00000000 MOVE : < >
OPA: 00 00000000 EDIT:

1-7
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
UPGRADE THE MAIN & LOADER PROGRAM
1. MAKING UPGRADE DISC
1) Do physical format as ISO9660 or JOLIET file
system
2) Don’t care about the CD Volume label
3) Write DR200 B_E & F_E file on Root
2. UPGRADE FLASH (MAIN & LOADER)
1) Put Upgrde DISC on the Set
2) After Disc Reading, You can see below screen
3) Press ENTER (or OK) KEY.
You can see both current and upgrade version.
4) Press PLAY KEY.
Start upgrading.
5) After upgrading, Automatically open tray.
Eject the Disc.
Reboot the Set
*OPTIONAL PARTS
1) B_E
LG_DR200_MV3PAL.ROM
2) F_E
mv44.rom
*OPTIONAL PARTS
1) MAIN
ONLY B_E UPGRADE
2) LOADER
ONLY LOADER UPGRADE
3) ALL
B_E & LOADER UPGRADE

1-8 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SPECIFICATIONS
• GENERAL
Power requirements AC 100 ~ 240V, 50/60Hz
Power consumption 30W
Dimensions (approx.) 430 X 54 X 285mm (w x h x d) without foot
Net weight (approx.) 3.5 kg
Operating temperature 5°C to 35°C
Operating humidity 5% to 90%
Television system PAL B/G color system
Recording format PAL
• RRECORDING
Recording format DVD Video Recording, DVD-VIDEO
Recordable media HDD (80/160GB), DVD-ReWritable, DVD-Recordable, DVD+ReWritable,
DVD+Recordable
Recordable time DVD (4.7GB): Approx. 1 hour (XP mode), 2 hours (SP mode),
4 hours (LP mode), 6 hours (EP mode), 11 hours (MLP mode)
HDD (80/160GB, MPEG2 Recording): Approx. 18/37 hours (XP mode),
37/75 hours (SP mode), 75/149 hours (LP mode),
112/223 hours (EP mode), 233/477 hours (MLP mode)
Video recording format
Sampling frequency 27MHz
Compression format MPEG 2 (VBR support)
Audio recording format
Sampling frequency 48kHz
Compression format Dolby Digital
• PLAYBACK
Frequency response DVD (PCM 48kHz): 8Hz to 22kHz, CD: 8Hz to 20kHz
DVD (PCM 96kHz): 8Hz to 44kHz
Signal-to-noise ratio More than 100dB (AUDIO OUT connector)
Harmonic distortion Less than 0.008% (AUDIO OUT connector)
Dynamic range More than 95dB (AUDIO OUT connector)
• INPUTS
ANTENNA IN Antenna input, 75ohms
VIDEO IN 1.0Vp-p 75ohms, sync negative, RCA jack x 1
AUDIO IN 2.0Vrms more than 47kohms, RCA jack (L, R) x 1
• OUTPUTS
COMPONENT VIDEO OUT (Y) 1.0V (p-p), 75Ω, sync negative, RCA jack x 1
(PB)/(PR) 0.7V (p-p), 75Ω, RCA jack x 2
Audio output (digital audio) 0.5V (p-p), 75Ω, RCA jack x 1
Audio output (analog audio) 2.0Vrms (1kHz, 0dB), 600Ω, RCA jack (L, R) x 1

2-1
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
EXPLODED VIEWS .....................................................................................................................................2-2
1. CABINET AND MAIN FRAME SECTION ..................................................................................................2-2
2. DECK MECHANISM SECTION ......................... .......................................................................................2-3
3. PACKING ACCESSORY SECTION...........................................................................................................2-4

2-2 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SVC purchase order caution
Key board is array coming timer board.
Purchase order board separately supply
incomprehensible.
Supply is possible in Location No A50
state in exploded views.
A50
A43
A43A
275
452
452
275
A44
A52
462
250
462
462
I/O BOARD
B
F
CABLE1
465
465
320
260
261
261
261
465
300
468
465
E
C
468
A47
SMPS
273
CABLE4
468
452
CABLE2
A
B
E
C
D
463
280
286
285
D
104
101
410 468
468
410
A53
A26
CABLE11
CABLE10
A
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION
261
261
CABLE3

2. DECK MECHANISM SECTION [MV3(DR-10A 815): NEW]
1025
1041
1432
1437
1038
1011
1432
1020
1036
Main C.B.A
I/O
Interface
I/O
Interface
1001
1003 1002
A001
A002
1016
1013
1015
1012
1439
1047
1046
1014
OPTIONAL PART
1043 1045
1044
1042
1018
1018
1019
DR-10 : IN, SH ONLY DR-10 : PT ONLY
1043 1045
A005
1030
1431
261
To Confirm
DR-10A 815
(NEW)
Difference Point
(Configuration)
To Confirm
DR-10A 815
(NEW)
2-3
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
1026
1017
A005
1019
A46
1433
1432

2-4 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. PACKING ACCESSORY SECTION
808 Battery
Cable, Coaxial
Plug Ass'y, 1Way (BLACK)
Plug Ass'y, 2Way
Bag
Packing
Remote Control
Instruction Ass'y
Packing
810 Accessory Ass'y
Box
806
804
803
811
Plug Ass'y, 1Way (YELLOW)
813
812
801
900
802
803
FLAT CABLE
822
OPTIONAL PARTS
832 DISC
821 SCART CABLE

3-1
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
SECTION 3
ELECTRICAL
CONTENTS
VDR PART
ELECTRICAL TROUBLESHOOTING GUIDE.....................................................................................3-2
1. POWER SUPPLY ON SMPS BOARD ...................................................................................................3-2
2. POWER SUPPLY ON I/O BOARD ........................................................................................................3-4
3. SYSTEM CIRCUIT PART.......................................................................................................................3-8
4. DISC NOT RECOGNIZED .....................................................................................................................3-8
5. WHEN PLAYING DISC, NO AUDIO OUTPUT.......................................................................................3-9
6. NO OPTICAL/DIGITAL OUTPUT .........................................................................................................3-10
7. NO TUNER AUDIO OUTPUT ..............................................................................................................3-10
8. NO RGB/COMPONENT VIDEO SIGNAL WHEN PLAY DISC.............................................................3-11
WIRING DIAGRAM ....................................................................................................................................3-13
1. CONNECTOR PICTURE ....................................................................................................................3-13
BLOCK DIAGRAMS ..................................................................................................................................3-15
1. POWER 1 BLOCK DIAGRAM..............................................................................................................3-15
2. POWER 2 BLOCK DIAGRAM..............................................................................................................3-17
3. RESET/IF/CLOCK BLOCK DIAGRAM.................................................................................................3-19
4. AV DIGITAL DATA/ADD SIGNAL BLOCK DIAGRAM ..........................................................................3-21
5. RF(FRONT END) & OPTION SIGNAL BLOCK DIAGRAM .................................................................3-23
6. AV ANALOG SIGNAL BLOCK DIAGRAM............................................................................................3-25
CIRCUIT DIAGRAMS................................................................................................................................3-27
1. POWER CIRCUIT DIAGRAM ..............................................................................................................3-27
2. DDR I/F CIRCUIT DIAGRAM...............................................................................................................3-29
3. HOST I/F CIRCUIT DIAGRAM.............................................................................................................3-31
4. VIDEO I/F CIRCUIT DIAGRAM ...........................................................................................................3-33
5. ATAPI CIRCUIT DIAGRAM ..................................................................................................................3-35
6. I/O I/F & AUDIO CIRCUIT DIAGRAM ..................................................................................................3-37
7. F-END & POWER CIRCUIT DIAGRAM...............................................................................................3-39
8. RF & MOTOR CIRCUIT DIAGRAM .....................................................................................................3-41
9. GND & POWER CIRCUIT DIAGRAM..................................................................................................3-43
10. MV3 DR TIMER CIRCUIT DIAGRAM..................................................................................................3-45
11. I/O µ-COM CIRCUIT DIAGRAM ..........................................................................................................3-47
12. TUNER/MPX/ADC/DAC/JACK CIRCUIT DIAGRAM ...........................................................................3-49
13. AUDIO ADC/SW/DAC CIRCUIT DIAGRAM ........................................................................................3-51
14. SMPS CIRCUIT DIAGRAM .................................................................................................................3-53
15. HDD JUNCTION CIRCUIT DIAGRAM ................................................................................................3-55
CIRCUIT VOLTAGE CHART...................................................................................................................3-57
PRINTED CIRCUIT DIAGRAMS............................................................................................................3-63
1. MAIN P.C.BOARD ................................................................................................................................3-63
2. I/O P.C.BOARD ....................................................................................................................................3-67
3. POWER P.C.BOARD ...........................................................................................................................3-71
4. TIMER & KEY P.C.BOARD ..................................................................................................................3-73
5. HDD JUNCTION P.C.BOARD ..............................................................................................................3-74

3-2 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
VDR PART
ELECTRICAL TROUBLESHOOTING GUIDE
1. POWER SUPPLY ON SMPS BOARD
No 5.3VA
YES
Is the F101 normal? Replace the F101 (Use the same fuse)
YES
NO
Is the BD101 normal? Replace the BD101
YES
NO
Is the R101 normal? Replace the R101
YES
NO
Is Vcc (13V ~ 27V)
supplied to IC101 pin2? Is the D102 normal?
YES
NO
Is there about 2.5V at
the IC103 pin1? Replace the IC103
NO
Check or Replace the D102
Is the D128 normal? Replace the D128
YES
NO
YES
Is the IC102 normal? Replace the IC102
YES
NO
Is the D121 normal? Replace the D121
YES
NO
Is the D122 normal? Replace the D122
YES
NO
Is the D125 normal? Replace the D125
YES
NO
Is the D124 normal? Replace the D124
YES
NO
Is the D127 normal? Replace the D127
YES
NO
Is the D126 normal? Replace the D126
YES
NO
Power Line of Main PCB is short
NO

3-3
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
ELECTRICAL TROUBLESHOOTING GUIDE
No 12V
Is the 13.5V
supplied to IC155 pin1? Check or Replace the D124
YES
YES
NO
Is the IC155 pin4 “H”? Check the DVD CTL ‘H’
signal from µ-com
YES
NO
Check or Replace the IC155
No 5V
Is the 5.5V
supplied to IC156 pin1? Check or Replace the D125
YES
YES
NO
Is the IC156 pin4 “H”? Check the DVD CTRL ‘H’
signal from µ-com
YES
NO
Check or Replace the IC156

3-4 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
No 12VT
Check D127 on SMPS
Board and Replace
YES
YES
NO
Is the VCC (14V)
supplied to Q164 Collector?
Check Q164 and Replace
YES
NO
Is there about 12.5V at
ZD151 & Q164 Base?
Check D128 on SMPS
Board and Replace
YES
NO
Is the VCC (33V)
supplied to Q162 Emiter?
Check Q162 and Replace
YES
NO
Is there about 0V at
Q162 Base?
Check the “TIMER_H”
signal from µ-COM
YES
NO
Is there
about 5V at R181 and 0.7V at
Q155 Base?
Check Q152 and Replace
2. POWER SUPPLY ON I/O BOARD
ELECTRICAL TROUBLESHOOTING GUIDE

3-5
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
No 5VT
Is the VCC (5.3V)
supplied to Q155 Emiter? Check 5.3VA on SMPS Board
YES
YES
NO
Is there
about 0V at D152 and
Q152 Collector? Check Q155 and Replace
YES
NO
Is there
about 5V at R180 and 0.7V at
Q152 Base?
Check the “TIMER H”
signal from µ-COM
YES
NO
Check Q152 and Replace
No 33VT
Is the VCC (33V)
supplied to Q161 Emiter? Check D128 on SMPS
Board and Replace
YES
YES
NO
Is there about 0V at
Q152 Collector? Check Q161 and Replace
YES
NO
Is there
about 5V at R180 and 0.7V at
Q152 Base?
Check the “TIMER H”
signal from µ-COM
YES
NO
Check Q152 and Replace
ELECTRICAL TROUBLESHOOTING GUIDE

3-6 Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
No 5.0VD
Is there
about 5.3V at the IC153
pin1?
Check 5.3VA on SMPS Board
YES
YES
NO
Is there
about 4V ~ 5V at the IC153
pin4?
Check the “PWR CTL H”
signal from µ-COM
YES
NO
Check the IC153 and Replace
No 2.5V
Is there
about 3V ~ 3.8V at the IC151
pin1?
Check D154 and D123
on SMPS Board
YES
YES
NO
Is there
about 4V ~ 5V at the IC151
pin4?
Check the “PWR CTL H”
signal from µ-COM
YES
NO
Check the IC151 and Replace
ELECTRICAL TROUBLESHOOTING GUIDE

3-7
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
No 3.3V
Is there
about 3.8V at the IC152
pin1?
Check D123 on SMPS
Board and Replace
YES
YES
NO
Is there
about 4V ~ 5V at the IC152
pin4?
Check the “PWR CTL H”
signal from µ-COM
YES
NO
Check the IC152 and Replace
No SW_5.3VA
Is the
VCC (5.3V) supplied to
Q158 Emiter? Check 5.3VA on SMPS Board
YES
YES
NO
Is there about 0V
at R179 and R156?
Check the “STANBY H”
signal from µ-COM
YES
NO
Check Q158 and Replace
ELECTRICAL TROUBLESHOOTING GUIDE