LG B1200 Schematics 4

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

- 30 -

4. TROUBLE SHOOTING

- 31 -

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.