LG FH2 User manual

SERVICE MANUAL
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
Internal Use Only
HIGH POWER
SPEAKER SYSTEM
MARCH, 2017P/NO : AFN77912803
MODEL: FH2
MODEL: FH2

1-1
CONTENTS
SECTION 1 ........ SUMMARY
SECTION 2 ........ CABINET & MAIN CHASSIS
SECTION 3 ........ ELECTRICAL

1-2
SECTION 1
SUMMARY
CONTENTS
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO PRODUCTS.................................................... 1-3
SERVICING PRECAUTIONS ............................................................................................................................ 1-4
• GENERAL SERVICING PRECAUTIONS
• INSULATION CHECKING PRODEDURE
• ELECTROSTATICALLY SENSITIVE (ES) DEVICES
HIDDEN KEY MODE ......................................................................................................................................... 1-5
PROGRAM DOWNLOAD & UPDATE GUIDE.................................................................................................. 1-6
SPECIFICATIONS ............................................................................................................................................. 1-7

1-3
PRODUCT SAFETY SERVICING GUIDELINES
FOR AUDIO 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 des-
ignators 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 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
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 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 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
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, con-
duit, 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 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
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.

1-4
SERVICING PRECAUTIONS
CAUTION: Before servicing the Audio 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
precautions in this publication, always follow the safety pre-
cautions.
Remember Safety First :
General Servicing Precautions
1.Always unplug the
Audio 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
Audio products 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
Audio products 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 resis-
tance 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 commer-
cially 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.)

1-5
HIDDEN KEY MODE
HIDDEN MODE AVAILABLE
STATUS
ENTRANCE
KEY(Audio) EXIT KEY DISPLAY RESULT
Factroy Reset
POWER ON
STATUS
MIC not connected
Custom code :
2C2C+0xF0(LG MP2)
b + B.Skip for 3s
Auto power off
SW version 2s
--> option 2s
--> E2P CLEAR
Initialize
Version Check
POWER ON
STATUS
MIC not connected
MIC + Function
for 3s
MIC + Function
for 3s
01140
OP 1F
Version move :
|<<, >>|
SYSTEM INITIAL
POWER ON
STATUS
MIC not connected
Voice canceller
+ F.Skip for 3s Auto power off “E2PCL”
EEPROM initialize
EEPROM (Backsup
data) Clear
OPTION EDIT
POWER ON
STATUS
MIC not connected
Voice canceller
+ REPEAT for 3s
Voice canceller
+ REPEAT for 3s OP--10
* Option Editer
- move : |<< , >>|
- change value :
sound effect
- save : play/pause
key
- exit : same to
ENTERANCE KEY
APD Test Display
POWER ON
STATUS
MIC not connected
Voice canceller
+ Play/Pause for 3s
Voice canceller
+ Play/Pause for 3s
MM:SS (AUX mode
--> HH:MM:SS)
* Display APD Timer
HH=hour,
MM=min, SS=sec
Sound BYPASS
POWER ON
STATUS
MIC not connected
MIC + F.Skip
for 3s
SOUND EFFECT
key Display “BYPAS” 3s Changed EQ to BYPASS
* If you change Main PCB or Flash memory, please set appropriate value of option for region with option
edit hidden key.
Option Value Region
0x5F EU, Russia
0x3F North America, South America
0x1F Aisa, Africa, ETC.

1-6
Caution:
• When downloading the file, you should neither unplug the USB device, change to the other function,
nor power off the device.
• USB device must be unplugged when the downloading process is completed.
If security program (Water Wall) is activated on your PC, you must save the file to the USB storage device and
disable the security software, then download the file to your set.
1. Main Program
1) File name is FH2_CODE_yymmddNo.bin
2) Put upgrade file into USB root directory. (No other file exist on root directory)
3) Change the mode to USB mode.
4) Insert the USB storage device to the USB port on the unit.
5) It will start update process automatically with showing “FW UP” on Display window.
6) If the update is finished, the set will turn off automatically.
PROGRAM DOWNLOAD & UPDATE GUIDE

1-7
GENERAL
Power requirements Refer to the main label on the unit.
Power consumption Refer to the main label on the unit.
Dimensions (W x H x D) Approx. 352.5 mm x 419.6 mm x 269.2 mm
Net Weight Approx. 9.71 kg
Operating temperature 5 °C to 45 °C
Operating humidity 5 % to 60 %
Maximum operating altitude 2000 m
INPUTS
Portable in (PORT. IN) 2.0 Vrms (3.5 mm stereo jack) x 1
Microphone (MIC) Sensitivity 30 mV (1 kHz), 6.3 mm jack x 1
TUNER
FM Tuning Range 87,5 to 108.0 MHz or 87,50 to 108,00 MHz
SYSTEM
Frequency Response 40 to 20,000 Hz
Signal-to-noise ratio More than 75 dB
Dynamic range More than 80 dB
Bus Power Supply (USB) 5 V 500 mA
AMPLIFIER (RMS Output power)
Total output 50 W (4 Ωat 1 KHz, 10 % THD)
BATTERY
Battery type 12 V/7.0 Ah (Valve Regulated Lead-Acid rechargeable battery)
Operating time Approx. 15 hours
(Based on fully charging the battery and continuous playback
using 50 % volume level.)
It may vary depending on the battery status and operational conditions.
Charging time Approx. 9 hours
It may vary depending on the battery status and operational conditions.
CAUTION:
During storage of the battery, charge it at least once every six months.
If the battery is stored for a long period without being charged, its battery life may be shortened.
Design and specifications are subject to change without notice.
SPECIFICATIONS

1-8

2-1
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
HOW TO DISASSEMBLE THE BATTERY ....................................................................................................... 2-2
DISASSEMBLY & ASSEMBLY INSTRUCTIONS............................................................................................. 2-3
1. DISASSEMBLY GUIDE ............................................................................................................................ 2-3
2. ASSEMBLY STRUCTURE AND METHOD .............................................................................................. 2-4
EXPLODED VIEWS ........................................................................................................................................... 2-7
1. CABINET AND MAIN FRAME SECTION ................................................................................................. 2-7
2. PACKING ACCESSORY SECTION ......................................................................................................... 2-9

2-2
HOW TO DISASSEMBLE THE BATTERY
2) Remove the bottom cover.1) Remove the screws.
4) Remove the battery.3) Disconnect the battery cable.
Battery

2-3
DISASSEMBLY & ASSEMBLY INSTRUCTIONS
1. DISASSEMBLY GUIDE
※ Please be careful so as not to cause scratches during disassembly.
4) Battery assembly (Screw BM4)3) SMPS PCB assembly (Screw PA3)
2) Top panel assembly1) Front panel assembly (Screw PA3)

2-4
2. ASSEMBLY STRUCTURE AND METHOD
Note: Disassembly is reverse of the assembly method.
4) Battery assembly (Screw BM4)3) Top panel assembly
6) SMPS PCB assembly (Screw PA3)5) Front panel assembly (Screw PA3)
2) Side Handle assembly (Screw KA3.5)1) Tweeter Woofer assembly (Screw PA3.5)

2-5
9) Final products
Figure) Top panel assembly (Screw PA3)
8) Foot/ Wheel rubber assembly (Screw PWM4/ Screw PA3) 7) Handle assembly (Screw BM4)
ASSEMBLY STRUCTURE AND METHOD

2-6

A
H
G
E
D
F
B
A
D
I
E
M
F
B
G
P
O
CN
C
J
K
L
G
H
I
M
J
K
N
L
O
P
251
A42
A52
A46
A55
253
262
263 A44
270
265
548
546
546
548
265
548
548
547
264
274
273
272
A47
271
271
271 553
553
553 551
551
551
275
549
A53
552
551
A54
551
552
264
550
547
551
551
260
549
545
261
261
550
550
545
A43
CABLE4
CABLE2
CABLE6
CABLE7
CABLE8
CABLE9
CABLE12
CABLE11
CABLE10
FM
VOL
CTL
MAIN
MIC
BT
FRONT
SMPS
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION
2-82-7

2. PACKING ACCESSORY SECTION
2-102-9
801 Owner’s manual
802 Box
300 Power cord
Packing
803T
Packing
803B

SECTION 3
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM ......................................................................................................................... 3-2
2. SPEAKER NO SOUND........................................................................................................................... 3-6
3. PORTABLE FUNCTION DOESN’T WORK ............................................................................................ 3-7
4. BT FUNCTION DOESN’T WORK........................................................................................................... 3-8
ELECTRICAL TROUBLESHOOTING GUIDE................................................................................................... 3-9
1. SYSTEM POWER SUPPLY ON SMPS BOARD.................................................................................... 3-9
2. NO POWER .......................................................................................................................................... 3-12
3. NO BUTTON OPERATION................................................................................................................... 3-13
4. NO BT OPERATION............................................................................................................................. 3-14
5. NO AUDIO OUTPUT ............................................................................................................................ 3-15
WAVEFORMS OF MAJOR CHECK POINT.................................................................................................... 3-18
1. SYSTEM PART-1 (X-TAL).................................................................................................................... 3-18
2. SYSTEM PART-2 (I2S SIGNAL) .......................................................................................................... 3-19
3. SYSTEM PART-3 (I2C SIGNAL) .......................................................................................................... 3-20
4. SYSTEM PART-4 (PWM SIGNAL) ....................................................................................................... 3-21
5. SYSTEM PART-5 (BATTERY INPUT - AC OFF STATUS).................................................................. 3-22
WIRING DIAGRAM.......................................................................................................................................... 3-23
BLOCK DIAGRAMS ........................................................................................................................................ 3-25
1. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-25
2. POWER BLOCK DIAGRAM ................................................................................................................. 3-27
CIRCUIT VOLTAGE CHART........................................................................................................................... 3-29
1. ICs......................................................................................................................................................... 3-29
2. CONNECTORS..................................................................................................................................... 3-30
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-31
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-31
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-33
3. FRONT P. C. BOARD DIAGRAM......................................................................................................... 3-37
4. FM P. C. BOARD DIAGRAM ................................................................................................................ 3-39
5. VOLUME CONTROL P. C. BOARD DIAGRAM ................................................................................... 3-39
6. MIC P. C. BOARD DIAGRAM............................................................................................................... 3-41
3-1

3-2
ONE POINT REPAIR GUIDE
1. NO POWER PROBLEM
No power problem occurs when you power on the unit.
1-1. CON4 22 VA
1-1-1. Solution
Replace F1, IC8 on SMPS board.
1-1-2. How to troubleshoot (Countermeasure)
Case 1) AC/DC OUT has no voltage (Battery’s voltage): Check F1, R6, R8 and replace it.
Case 2) CON4 22 VA Abnormal: Check IC8, Q6, D10 and replace it.
1-1-3. Service hint (Any picture/ Remark)
< SMPS circuit >
< SMPS board view >
IC8
IC8
R8
R8
R6
R6
AC/DC OUT
AC/DC OUT
D10
D10
Q6
Q6
F1
F1
Q6
Q6
D10
D10
Case 1
Case 1
R6
R6
R8
R8
IC8
IC8
Case 2
Case 2
Case 2
Case 2
Case 1
Case 1

3-3
ONE POINT REPAIR GUIDE
NO POWER PROBLEM
No power problem occurs when you power on the unit.
1-2. No Charge
1-2-1. Solution
Replace F2, R6, R8 on SMPS board.
1-2-2. How to troubleshoot (Countermeasure)
Case 1) VD (11 V-15.3 V) Abnormal: Check AC TO DC circuit.
Case 2) CN1 (10.5 V-14.8 V) Abnormal: Check F2, R6, R8 and replace it.
1-2-3. Service hint (Any picture/ Remark)
< SMPS circuit >
< SMPS board view >
F2
F2
F2
F2
Case 1
Case 1
Case 2
Case 2
Case 2
Case 2
Case 1
Case 1