No video picture, no sound.
Check whether all the voltages
from the power board to the
decoder board are normal.
Check if the reset circuit consisting
ofCE7, D2 is normal (at a low level
for
constantly at 3.3V).
Check whether there is
27MHz signal output.
Check if there is 128MHz
signal output on R67.
Check if short-circuit and
bad solder exist on Pin
99
Reconnect the component in
No video picture,
no sound.
Yes
tens
of
milliseconds,
then
Yes
Yes
SDRAM(R67 DCLK) waveform
Yes
Yes
4-10
No
Check the loaded circuit
No
Change CE7, D2.
Crystal oscillator Y2 and
No
peripheral components
are defected or eroded.
No
Check whether
short-circuit or bad
solder on U4,U5
No
Trouble shooting chart
CVBS(R21 point) waveform
27Mhz waveform
No
Check U1.
Yes