LG U8290 Service Manual page 131

4. TROUBLE SHOOTING
MIDI Ring tone for speaker
MIDI Ring tone speaker path as below:
MSM6250 HPH_R, HPH_L → R648, R649 → C633, C634 → R622, R623 → U605(Amp) → CN300 →
CN2 → CN1 → LCD module → speaker
Start
Play Th e Ring tone
The Ring t one appe ar at
R648, R649?
The Ring Tone appear at
C633, C634?
LOUD_SPK_EN is
2.6V?
The Ring Tone appear at
CN300 pin 2,3?
The Ring Tone appear at
CN2 pin 2, 3?
The Ring Tone app ear at
SPK+/SPK- in LCD mod ule?
Solder ing if speaker OK?
Can you hear the tone?
END
NO
Change the Main b oard
YES
NO
Change the Main board
YES
NO
Change the Main board
YES
NO
R648,R649,C633,C634,
Change the Main b oard
YES
NO
NO
Change the LCD Module
YES
NO
YES
NO
YES
- 132 -
Check R 648,R649 or
Check
R622,R623 or
Change the Key pcb
Resoldering speaker
Change the speaker