If no audio is output through JP800 while the system is normal, first check the
CPU AUDIO output and clock. [I2S interface ].
If no problems were found, check the U671 for Audio DAC.
A/V Inspection
No Audio Output
Preliminary Checkpoints
< Waveform 10 >
< Waveform 11 >
Check the CPU
12S output
No Audio Output
Check the Audio clock
Pin 9 of U261
Check for other
defective modes
Waveform 10
Ch1:SCLK,
Ch2:LRCLK,
Ch3:ADATA0
Check the path between
CPU and Clock
(Incorrect insertion, poor soldering,
short circuits, damage, etc.)
Check the path between
Audio DAC and CPU
(Incorrect insertion, poor solding,
short circuits, damage, etc)
Check the X-TAL and U261
(Incorrect insertion, poor soldering,
short circuits, damage, etc)
NG
OK
OK
OK
NG
Check the Audio DAC for
U761
OK
NG
Useful Tips
1. The Audio problem largely from the defect of CPU, Audio DAC or incomplete soldering of the parts located along
the audio output path.
2. Audio DAC pins represent serial data, LR clock, Bit clock and system clock, respectively.
Waveform 11
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