Videocon Mstar MST719, Mstar MST719DU, Руководство по обслуживанию

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MST719 Service Manual
33
4). No Sound
NO
NO
NO
Firstly Check if audio Source input
is ok.
Check if the U16 TAS5707 pin 19
voltage is high to 3.6V, Check the
pin23,24 software is ok.
Check if the power supply FB8 12V
is ok, FB5,FB16 +3.3V is OK.
Check the Q23,Q21 and the I2C
circuit.
Check the CN21 pin 8,9 power
supply output 12V OK or not.
1 .U27 PCM1808 is the ADC IC,If not
sound output to speaker, need
check this IC work status, please
check the power supply: +3.3V and
5VS is ok or not.
2
.U28 is the
crystal oscillation driver IC, check
the pin6 +3.3V is OK then check
the frequency of pin6 is 12.288M
Check the power supply circuit or
change the component of crystal.
Check the audio switch ICs U14,U26
power supply voltage is ok, check
the logic control is ok,
Y
Y
Check the power supply board.
N
Y
Y
If all of the condition are ready and
the
relevant
periphery components
are checked is OK, finally try to
change the IC of
U16/U27/U28/U14/U26.
Y