Service Manuals, User Guides, Schematic Diagrams or docs for : LG Audio CM2540 service
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Internal Use Only
Website http://biz.lgservice.com
SERVICE MANUAL
MICRO HI-FI SYSTEM
SERVICE MANUAL
MODEL: CM2540
MODEL: CM2540
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS"
IN THIS MANUAL.
P/NO : AFN76932794 JANUARY, 2015
CONTENTS
SECTION 1 ........ GENERAL
SECTION 2 ........ CABINET & MAIN CHASSIS
SECTION 3 ........ ELECTRICAL
SECTION 4 ........ REPLACEMENT PARTS LIST
1-1
SECTION 1
SUMMARY
CONTENTS
SERVICING PRECAUTIONS ................................................................................................................... 1-3
ESD PRECAUTIONS .................................................................................................................................. 1-5
OPTION & HIDDEN KEY .......................................................................................................................... 1-6
1. HOW TO CHECK S/W VERSION NUMBER?
2. HOW TO MAKE A SYSTEM RESET?
3. HOW TO SET THE SYSTEM OPTION?
4. HOW TO SET THE DOOR LOCK OPTION?
5. HOW TO UPGRADE MAIN AND SUB MCU FIRMWARE?
SPECIFICATIONS ....................................................................................................................................... 1-8
1-2
SERVICING PRECAUTIONS
NOTES REGARDING HANDLING OF THE PICK-UP
1. Notes for transport and storage
1) The pick-up should always be left in its conductive bag until immediately prior to use.
2) The pick-up should never be subjected to external pressure or impact.
Storage in conductive bag Drop impact
2. Repair notes
1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.
2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and
impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or
damage to the printed-circuit board.
3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason
the adjustment point and installation screws should absolutely never be touched.
4) Laser beams may damage the eyes!
Absolutely never permit laser beams to enter the eyes!
Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.
NEVER look directly at the laser beam, and don't allow
contact with fingers or other exposed skin.
5) Cleaning the lens surface
If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used
for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cotton
swab should be used, taking care not to distort lens.
Pressure
Magnet
Pressure
How to hold the pick-up
Cotton swab
Conductive Sheet
6) Never attempt to disassemble the pick-up.
Spring has excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab.
(Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much
of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.
1-3
NOTES REGARDING COMPACT DISC PLAYER REPAIRS
1. Preparations
1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These components
are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, components
can be damaged, and for that reason components should be handled with care.
2) The pick-up is composed of many optical components and other high-precision components. Care must be
taken, therefore, to avoid repair or storage where the temperature or humidity is high, where strong magnet-
ism is present, or where there is excessive dust.
2. Notes for repair
1) Before replacing a component part, first disconnect the power supply lead wire from the unit
2) All equipment, measuring instruments and tools must be grounded.
3) The workbench should be covered with a conductive sheet and grounded.
When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is
because there is the possibility of damage by static electricity.)
4) To prevent AC leakage, the metal part of the soldering iron should be grounded.
5) Workers should be grounded by an armband (1 M)
6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent stat-
ic electricity changes in the clothing to escape from the armband.
7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.
Armband
Resistor
(1 M)
Resistor
Conductive
(1 M)
Sheet
1-4
ESD PRECAUTIONS
Electrostatically Sensitive Devices (ESD)
Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components
commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD 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 ESD 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 ESD 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 ESD devices.
5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESD
devices.
6. Do not remove a replacement ESD device from its protective package until immediately before you are
ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by
conductive foam, aluminum foil or comparable conductive materials).
7. Immediately before removing the protective material from the leads of a replacement ESD device, touch the
protective material to the chassis or circuit assembly into which the device will by installed.
CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER
SAFETY PRECAUTIONS.
8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise 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 ESD device).
CAUTION. GRAPHIC SYMBOLS
THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS
INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED
"DANGEROUS VOLTAGE" THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF
ELECTRIC SHOCK.
THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE
SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE
LITERATURE.
1-5
OPTION & HIDDEN KEY
1. How to check S/W version number?
Step 1: Press and hold Stop key (Set) + Press and hold Play key (RMC).
"CM2540_VER03_01/17_000 MCU VER03"
----------- -------- ------ -----------
Bx8805 Month/Date Option Sub MCU
Step 2: To return to Previous screen, repeat Step1 operation.
Step 3: In Step1 status, if press Prev Key on set, full screen display will be appeared.
< Full screen display >
Step 4: In Step3 status, if press Next key on set, the key tesing mode will be started as below.
"KEY - ----
01"
Key number
Step 5: Press and hold Stop key on set, the system will be returned to normal screen mode.
2. How to make a system reset?
Step 1: Press and hold Stop key (Set) + Press and hold key (RMC).
"E2P CLEAR"
Step 2: After 2 seconds, the system will be power off automatically,
and all of system data will be reset except system option.
3. How to set the system option?
Step 1: Press and hold Stop key (Set) + Press and hold key (RMC).
"OPT 0000"
Option Table
Digit 3 Digit 2 Digit 1 Digit 0
0 : 87.5 kHz ~ 108 MHz
0 : FM/RDS (50 kHz step) 0 : Support ID3/TAG display 0 : USB record
1 : FM only 1 : 87.5 kHz ~ 108 MHz 1 : Not support 1 : Not support
(100kHz step)
Step 2: To change digit number, press or keys on RMC.
Step 3: To change option value, press REPEAT key on RMC.
Step 4: To confirm current settings, repeat Step1 operation.
"E2P CLEAR"
Step 5: After 2 seconds, the system will be reset automatically. And new option is applied to system.
1-6
4. How to set the door lock option?
Step 1: In CD mode, press and hold Stop key (Set) + Press and hold Stop key (RMC).
"LOCKED" : after setting, the CD Door can`t be opened.
Step 2: In CD mode, to change "Unlock" option, press and hold Stop key (Set) + Press and hold STOP Key (RMC).
"UNLOCKED"
< EQ Pattern> : Only CM2540 model.
Natural -> Auto Eq -> Pop -> Classic -> Jazz -> Rock -> MP3_Opt -> Bass Blast -> Bypass
5. How to upgrade main and sub MCU firmware?
1) Upgrade Main MCU (MCS Bx8805) : Firmware name is "CM2x40_VERxx_xxxxxx. MCS"
Step 1: All of files in USB drive should be removed. Then copy firmware to USB device.
Step 2: In USB mode, insert USB device to socket. Then upgrade process will be started automatically as below.
"NO USB" "SEARCH" "UPGRADE"
Step 3: After finishing upgrade firmware, "SUCCESS" message will be shown during 2 seconds.
Then the set will be power off automatically.
"SUCCESS"
2) Upgrade Sub MCU (Samsung S3F8419) : Firmware name is "CM2x40_MCU_VERxx_xxxxxx.BIN "
Step 1: All of files in USB drive should be removed. Then copy firmware to USB device.
Step 2: In USB mode, insert USB device to socket. Then upgrade process will be started automatically as below.
"NO USB" "SEARCH" "MCU UP"
Step 3 : During upgrading, the progress will be shown as below
"[13]" ..."[73]"....... "[100]"
Step 4 : After finishing upgrade firmware, "Success" message will be shown without auto power off.
So user need to plug out AC code for restarting the set.
"SUCCESS"
1-7
SPECIFICATIONS
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