LG B1200 Schematics 5

Page 1
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 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 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
V
V
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Page 2
4. TROUBLE SHOOTING
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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.
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4. TROUBLE SHOOTING
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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
Page 4
4. TROUBLE SHOOTING
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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.
Page 5
4. TROUBLE SHOOTING
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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.
Page 6
5. TEST POINT DATA
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5. TEST POINT DATA
Component Side (1-1)
9
10
6
4
1
2
3
5
7
8
11
12
13
16
15
14
Page 7
5. TEST POINT DATA
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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
Page 8
5. TEST POINT DATA
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Component Side (1-2)
18
19
20
21 22
23
25 24
26
27
28
30 31
32
33 29
Page 9
5. TEST POINT DATA
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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
Page 10
5. TEST POINT DATA
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Keypad Side (2-1)
1
2
3
5
7
4
6
Page 11
5. TEST POINT DATA
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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
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