DVB-C Set Top Box Hardware repare guaid–Can not power on

When you got one DVB-C Set Top Box,and plug the adapter,but can not be opened,please check as follow:

1.Plug  our power adater(12V 1A) into the box’s DC jack.

2.Check main board 5V,1.8V,1.1v and 3.3v’s output is normal or not,Checking the voltage of the pin at the end of the chip is more useful than checking the output of the power supply.

3.Check the vibration of the crystal oscillator—–Use the multimeter and check if the voltage is about 1.5V.

4.Check the DDR voltage is 1.5V or not.

5.Check the reset chip 809 is normal or not,if it’s high level than normal.

6.If all the above checked,but still can not open the box,than burn the new software flash.

7.If all the above resolved,but still can not open the box,than change the main chip.