The computer rather seldom fails. But from time to time nevertheless its separate components can demand repair or even replacement. The main thing here is to carry out the correct diagnostics of fault and to establish the breakage reason. Sometimes in practice of the user of the personal computer there is need to check serviceability of power supply unit. Whether it is possible to make it independently, without resorting to the help of experts?
It is required to you
- - CD ROM drive;
- - magnifying glass;
- - ohmmeter;
- - oscillograph.
Instruction
1. To check serviceability of power supply unit of the computer without connection of the motherboard, first of all, connect some loading to power supply unit. It can be CD ROM or the disk drive for floppy disks. Close short green wire in the connector of power supply unit and any of its black wires. It is possible to make it by means of normal office paper clip. Include power supply unit. If the block is serviceable, the fan will begin to work at once and the LED of the device (drive) connected as loading will join.
2. If the power supply unit is faulty, then one of the most possible reasons – failure of parts in the high-voltage filter, key, rectifiers or in PWM controller chip. For a start check the safety lock facing the surge filter. Replace the faulty safety lock with new with the same face value.
3. Using magnifying glass, make external inspection of the printed circuit board. Pay attention to printing conductors – they have to be without visible gaps, conclusions of parts should not dangle freely. One of signs of fault of mounting – ring-shaped cracks around part conclusion.
4. By means of ohmmeter check the rectifier of high frequency, the high-voltage filter and high-voltage key. Survey regarding break detection filter condensers (sign of break – "throws" when checking by ohmmeter). In the presence of oscillograph look at form of the straightened tension at the output of the filter, in case of fault the double amplitude of pulsations will exceed 5 V.
5. Check the protective diodes connected to conclusions of the collector and the emitter of transistors. Resistance "collector emitter" in the serviceable transistor has to be small or equal to zero in both directions.
6. If the power supply unit is not got, are heard only weak hum, the fan does not turn, then, most likely, one is punched or even both diodes in any of channels of +5 V, +12 V. Zamenita diodes on serviceable.
7. If the held events have not led to definition of failure cause of power supply unit, then it is recommended to ask for the help the expert for more exact diagnostics or to make replacement of the block by obviously serviceable.