Service Manuals, User Guides, Schematic Diagrams or docs for : LG Mobile Phone LG B1200 LG B1200 5
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3. FAILURE LIST
3. FAILURE LIST
FAILURE ITEM L1 L2 L3
NO RING TONE V
RING TONE DISTORTION V
NO KEY TONE V
AUDIO NOISE V V
POOR VOICE QUALITY V V
LOW VOICE VOLUME V V
RECEIVER / EARPIECE MUTE V V
POOR HANDFREE VOICE QUILITY V
TOTALLY DEAD/NO POWER V V
UNEXPECTED POWER ON V
UNEXPECTED POWER OFF / POWER OFF BY PLUG IN A EARPIECE V
RANDOM TIME DISPLAY V
CLOCK RESET AT POMER ON / CLOCK DEAD V V
NO SERVE FOUND/NO NET WORK REGISTER V
ROAMING AT POWER ON / UNEXPECTED INTERNATIONAL ROAMING V
WRONG IMEI CODE V
LCD NOT DISPLAY V
LCD DISPLAY MISSING ROW/LCD DISPLAY DETECT V
BLACK LCD V
FLICKING LCD DISPLAY / DISPLAY UNSTABLE V
BLACK LINE ON LCD DISPLAY V
RANDOM LCD DISPLAY V
LED FAIL V
WEAK SINGAL/ECHO IN TALKS V
NO TRANSMIT / RECEIVE V
ANTENNA DEFECT V
INCOME CALLS CAN'T BE PICKED UP V
REMOTE SIDE AUDIO MUTE V V
SIGNAL INTERCEPT V
BAD CHARGER CONNECTOR V
CAN'T POWER ON AFTER CHARGING V V
SHORT WAITING HOURS V V
HIGH POWER CONSUMATION V V
BATTERY DAMAGE V
BATTERY CAN'T BE CHARGED V
BATTERY LEVEL DON'T DISPLAY V
BATTERY LEVEL DISPLAY NOT CORRECT V
INCOMPATIBLE WITH BATTERY V
SIM CARD UNRECOGNIZE V V
BAD SIM CARD CONTACT V
UNEXPECTED SIM CARD LOCK V
HOUSING DAMAGE V
BAD KEYPAD RESPONSE V V
- 30 -
4. TROUBLE SHOOTING
4. TROUBLE SHOOTING
Power Supply Failure
a) Failure :
- Problem with turning on mobile phone
Solution:
- Test the set's current by using battery
simulator: observe the value of current used
- Case 1:
If the Current is higher than 300mA, please
check C223~C227, if short circuit, Replace it.
- Case 2:
In the case the current is between 10 and 30mA,
The cause could be FLASH ROM(U301) defect,
please use monitor to re-install software. If the
software can't be re-install through serial port,
use JTAG interface to re-install software.
b) Failure :
- Problem with charging the battery
- Charging connector damage
Solution :
- J104 may be bad connection or broken, check
the connector.
- J104 may be a cold soldering, Please re-solder
again.
- If J104 is broken, replace the connector
carefully
c) Failure :
- The value of the charging current look like short
circuit.
Solution :
- Re-install the software
- Check Q101, if short circuit, replace it.
- 31 -
4. TROUBLE SHOOTING
Software Download Failure
a) Failure :
- Problem with software download
Solution :
- J104 may be bad connection or broken, check
the connector.
- J104 may be a cold soldering, Please re-solder
again.
- Check R104,R105& R109, if cold soldering,
Please re-solder again.
Voice Function Failure
a) Failure :
- Microphone voice failure
Solution :
- Check M301, the microphone holder may be
bad connection
- Test the bias voltage on R301, it should be
2.5V,
- Replace Microphone, if microphone holder &
bias voltage is fine.
b) Failure :
- Speaker failure
Solution :
- check speaker connector, it may be bad
connection.
- Check U302 and related circuit, if short circuit,
replace it.
c) Failure :
- Headset function failure
Solution :
- J104 may be bad connection or broken, check
the connector.
- J104 may be a cold soldering, Please re-solder
again.
- If J104 is broken, replace the connectorcarefully
- 32 -
4. TROUBLE SHOOTING
Display Function Failure
a) Failure :
-No display on LCD
Solution :
-Test the capacitance of C319~C327 by using
multi-meter, the value should be infinity.
Replace the capacitor, which has any
impedance.
- Test the resistance of R311~R313, if cold
soldering, Please re-solder again.
- Otherwise, replace LCD module .
b) Failure :
- Broken LCD
Solution :
- Replace whole LCD module.
- Solder the LCD module with care.
c) Failure :
-Fails on dark display, black line, short of lines,
unstable brightness
Solution :
- Test R311,~R313, if cold soldering, Please re-
solder again.
- Test C319~C327, if cold soldering, Please re-
solder again.
- Otherwise, Replace whole LCD module.
- 33 -
4. TROUBLE SHOOTING
d) Failure :
- No Back-light
Solution :
- Replace the LED that doesn't light up including
any failing parts of LED.
- If all of the LED fails, Please check Q301,
Q302 and related circuits.
- 34 -
5. TEST POINT DATA
5. TEST POINT DATA
Component Side (1-1)
1
2
3
13
4
11 5
6 7
14
12 8
16
9
15
10
- 35 -
5. TEST POINT DATA
Location Component Side (1-1)
1 J103 Battery connector : For damage or cold soldering cause power on failure
2 Q101 P-channel MOSFET with schottky diode : For damage or cold soldering cause
charger function failure
3 U202 Nausica_CS : analog baseband chipset (ABB)
4 U201 Hercrom20 : digital baseband chipset (DBB)
5 U301 16Mbit flash ROM : For damage or cold soldering cause power on failure
6 U101 3V, 200mA LDO regulator : For damage or cold soldering cause accessory power
failure.
7 Q301 Isolated dual transistors : For damage or cold soldering Q301A cause vibration
motor Failure, Q301B cause keypad back-light failure
8 Q302 Isolated dual transistors : For damage or cold soldering Q302A cause pre-charger
indication failure, Q302B cause the LCD back-light failure
9 J301 Vibration motor : For damage or bad connection cause vibrator failure.
10 J104 System connector : For damage or cold soldering cause headset failure, trace/debug
/SW download failure
11 J102 SIM connector : For damage or bad connection cause SIM card failure.
12 U302 Audio amplifier : For damage cause speaker function failure.
13 Y201 32.768kHz crystal : For damage cause RTC function failure.
14 R104 8P4R resistor network : For damage or cold soldering cause trace/debug
R105 /SW download failure
R109
15 D313 Switching diode array : For damage or cold soldering cause the surge noise by
Vibrator
16 D102 Switching diode array : For damage or cold soldering cause the flash fast program
function failure
- 36 -
5. TEST POINT DATA
Component Side (1-2)
23 19
33 18
29 21
20
26 22
25
24
32
30
28 31
27
- 37 -
5. TEST POINT DATA
Location Component Side (1-2)
18 C223 VR2B regulator (2.85V) : For damage or cold soldering cause power supply for
DBB & ABB peripheral failure.
19 C224 VR1B regulator (2V) : For damage or cold soldering cause power supply for ABB
internal logic failure
20 C225 VR3 regulator (2.85V) : For damage or cold soldering cause power supply for
ABB analog circuits failure
21 C226 VR2 regulator (2.9V) : For damage or cold soldering cause power supply for
Memory device failure.
22 C227 VR1 regulator (1.8V) : For damage or cold soldering cause power supply for
DBB Core & RTC failure
23 C207 SIM regulator (3V/5V) : For damage or cold soldering cause power
C208 supply for SIM Interface failure
24 C206 VREF output (1.2V) : For damage or cold soldering cause power supply for
power on failure
25 R208 IBIAS output : For damage or cold soldering cause power supply for Power on
failure
26 R301 Microphone Input : For damage or cold soldering cause microphone failure
C304
C305
27 R110 Ext. audio Input : For damage or cold soldering cause external audio input failure
C107
28 C106 Ext. audio output : For damage or cold soldering cause external audio output
R107 failure
29 R207 ABB local Osc. generator : For damage or cold soldering cause ABB local Osc.
C205 failure
30 R307A Vibrator control : For damage or cold soldering cause vibrator failure
R308A
31 R307A Back-light control : For damage or cold soldering cause all back-light LED failure
R308A
32 R204 SIM card power control : For damage or cold soldering cause SIM card power
control failure.
33 R210 Uplink & downlink I/Q Filtering : For damage or cold soldering cause uplink or
R215 downlink I/Q signal failure.
C209
C210
- 38 -
5. TEST POINT DATA
Keypad Side (2-1)
1
7
2
4
3
5 6
- 39 -
5. TEST POINT DATA
Location Keypad Side (2-1)
1 LS301 Speaker : For bad connection cause speaker failure
2 DS301 LCM Connector : For damage or cold soldering cause LCD Display failure
3 D301~ Back-Light LED : For damage or cold soldering cause back-light LED failure
D312
4 S301~ Keypad Switches : For damage or shirt circuit cause keypad function failure
S317
5 M301 Microphone holder : For damage or cold soldering cause microphone failure
6 B201 Batter holder : For damage or cold soldering cause RTC function failure
7 Q601 T/R Switch transistor : For damage or cold soldering cause T/R Switch function
failure
- 40 -
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