Cause the cause of the failure is surrounded by channel signal formation process is: single chip MT1369EE (U3) audio decoding circuit from (149) foot (ABCK), (150 feet (ALRCK), (153) pin (PIN) the output clock, around the clock, audio data, were sent to audio signal. The two channel analog audio signal and then sent to the dual op amp u25 (C4558) 2 8 feet, after amplification from u25 1, 7 feet of output, the mute control circuit around the left and around the right output jack.a9tservice manual download site
AC-3 DVD playback, with an oscilloscope observation surround signal forming circuit of key points and found no analog audio signal output U621, 23 feet. Then measure the audio data input of the audio data input of the U6 around the audio data input of the.. Because the front left, front right, mid and high stress normal, indicating that the signal input U62 feet (aclk), 3 feet ABCK 4 feet ALRCK were normal, the tripod can be free, because the tripod in either foot input signal is not normal, will caused by six channel were silent fault, and measurement of single chip MT1639EE (153) feet for outputting audio data to estimate the fault for the pin existing weld, a signal connecting line, isolation resistance R168 open, the audio data signal is in the middle. Check for R168 resistor (33) end welding, after welding troubleshooting.a9tservice manual download site
Digital signal input DA1196 abnormal and fault rules is 2 feet (aclk) audio DAC external clock, 3 feet (ABCK) audio bit clock, 4 feet ALRCK about audio clock, in any signal abnormalities and no analog audio signal output six channels will cause DA1196, 5.1 channel were silent failures. And 5 feet (ADATAO), 6 feet ADTAT1, 7 feet ADTAT2 tripod either foot audio data input abnormal, general will only cause the channel correlation of abnormal sound, but the sound is normal. Such as 5 feet ADATAO no input signal, caused only 25 and 27 feet without analog audio signal output, front left, front right channel voice fault; and as 6 feet ADTAT1 no input signal, caused only 21 and 23 feet without analog audio signal output, appeared to surround the left. Surround right channel voice fault; another example is 7 feet ADTAT2) no input signal, caused only 17 and 19 feet without analog audio signal output, mid, no channel bass heavy sound fault. Normal DA11962, 3, 4 feet in the replay and stop both waveform, DC voltage were about 1.5V; 5 feet to play no matter any disc has the signal waveform, DC voltage is 1.5V, and in the end when no waveform. DC voltage variable 0V; pins 6 and 7 only when the other AC-3 playback of DVD discs and stops are silent, DC voltage is 0V. DAC audio circuit DA1196 normal working voltage (play DVD discs, see Table 4 state) in the measured data of road resistance.

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