Trouble shooting chart | ||
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No video picture, no sound.
No video picture,
no sound.
Check whether all the voltages | No |
from the power board to the |
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decoder board are normal. |
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Yes |
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Check the loaded circuit
CVBS(R1 point) waveform
Check if the reset circuit consisting of CE3, D6 and R21 is normal (at a high level for tens of milliseconds, then constantly at 3.3V).
Yes
Check whether there is 27MHz signal output.
Yes
No
Change CE3, D6 and R21.
27Mhz waveform
No | Crystal oscillator Y2 and | |
peripheral components | ||
| ||
| are defected or eroded. | |
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|
No
Check if there is 135MHz signal output on R31.
SDRAM(R31 PCLK) waveform
Yes
Check whether
No
Check if
Yes
Reconnect the component in
No
Check U2.
Yes