Trouble shooting chart | |
|
No video picture, no sound.
No video picture,
no sound.
Check whether all the voltages from the power board to the decoder board are normal.
Yes
Check if the reset circuit consisting ofCE1,Q1,Q2 is normal (at a low level for tens of milliseconds, then constantly at 3.3V).
Yes
No
No
Check the loaded circuit
Change CE1,Q1,Q2.
CVBS(R884 point) waveform
27Mhz waveform
Check whether there is 27MHz signal output.
Yes
No | Crystal oscillator Y1 and | |
peripheral components | ||
| ||
| are defected or eroded. |
Check if there is 135MHz signal output on R193.
No
Check whether
Yes
SDRAM(R193 DCLK) waveform | No |
Check if |
|
bad solder exist on Pin |
|
72 | No |
|
Yes
Reconnect the component in
Check U1.
Yes
