5. There may be water ripples electromagnetic radiation leakage power , the power of the magnetic field affected , interferes with the normal display of the display on the screen , if not pay attention to the long-term , the display may be magnetized.

 

6. Host often baffling restart This may be enough power supply , power supply computer power is not sufficient to bring all the equipment working properly , causing the system software running errors, hard drive, optical drive can not read and write, memory loss, etc. , so that the machine is restarted .

 

Second, the cause of the power failure

 

1 . Under normal circumstances a blown fuse , fuse main reasons: DC filter and transform the oscillation circuit in a high pressure job for too long, the voltage change is relatively large. Specific performance: breakdown diode circuit , high voltage electrolytic capacitors damage , damage to the inverter power switch . If indeed the fuse blows , you should first check the various components on the board , see the appearance of these elements have burned paste , there is no electrolyte overflow. If you do not find the above, then use a multimeter to measure if the two measured power switch e, c extreme resistance is less than 100kω, explained the switch is damaged. Followed by measuring the resistance value of the input , if less than 200kω, there is a partial description backend short circuit .

 

2 . No DC voltage output or voltage output instability if the fuse is intact , but under load conditions , no output DC voltage levels . This is mainly due to the following reasons : the power of the open circuit , short circuit , overvoltage , overcurrent protection circuit fails, the oscillation circuit is not working , the power is heavily loaded , high-frequency rectifier diode rectifier filter circuit breakdown , filter capacitor leakage and so on. At this time , the first with a multimeter measurement system board +5 v supply to ground resistance , if more than 0.8ω, then the board is no short circuit ; then the computer temporarily dismantle unnecessary hardware , such as hard drives, optical drives , etc., only leaving the motherboard , power supply, buzzer , and then measure the DC voltage of each output terminal , the output is zero if the time , you can certainly control circuit of the power failure .

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