The desktop power supply is not powered on. Solution 1:
1, if there is no power at all, it is a power supply problem, change the power supply.
2. Then there is the wrench problem. Most of them are motherboard power chip problems! In addition, the patch near the south bridge was burned.
The desktop power supply is not powered on. Solution 2:
There are many reasons why the computer power supply and motherboard are not powered on. Common causes and solutions are as follows:
1, the mains power is off, and then it is powered on after the mains power is normal.
2. The wires between the motherboard and the computer power supply are not connected properly, just connect all the wires. The wiring method is as follows:
3. The wiring of the boot button of the chassis is not well connected. Just connect the power SW terminal of the chassis to the power SW terminal on the motherboard.
4. The main chassis power key is not good. Replace the main chassis power key.
5, the power supply or motherboard is broken, just replace the corresponding bad things.
The desktop power supply is not powered on. Solution 3:
Use tweezers to short-circuit the green line and black line on the power plug, and then start the machine, and determine whether the problem lies in the coms circuit or the startup circuit.
Removing the coms battery and shorting the positive and negative poles can eliminate the BIOS problem.
When the power-on pin on the host is shorted with tweezers (the power-on pin next to the pin is missing from the 9 pins), the problem of poor contact of the power-on button can be eliminated.
If the above situation does not appear, then go and fix it. It may be the problem of the boot chip (dedicated boot chip or i/o) or the problem of the south bridge and the crystal oscillator, or the current limiting resistor in the circuit is broken by static electricity (this circuit is broken).
If it is the south bridge, don't repair it. It won't take long to fix it.
Related reading:
Introduction of high voltage pulse power supply
In radar navigation equipment, the transmitting part generally needs high-power pulse sources with high voltage, narrow pulse and different repetition frequencies. This kind of high-power pulse source generally boosts the commercial power to a DC high voltage of several thousand volts to several tens of thousands of volts through a high-voltage power supply, and then the DC high voltage is modulated into a pulse source with the pulse width and frequency required by the transmitting tube by a modulator.
The pulse source is mainly composed of high voltage power supply and modulator. The high-voltage power supply adopts switching regulated power supply, and the modulator adopts solid-state modulator of semiconductor devices.
The trigger pulse given by the user is a TTL level signal, so an interface circuit should be added before it is input to the isolation transformer. The interface circuit is used for the pre-amplification of TTL pulse signal and cooperates with isolation transformer. In order to achieve the purpose of isolation, users can provide power for this interface circuit, and manufacturers only need to put forward power requirements and design corresponding transformation and filtering circuits in the circuit.
The trigger pulse is isolated by pulse transformer, pre-modulator pulse shaping, power amplification and then trigger modulation board and cutoff board to work. The excitation pulse generated by the preprocessor is isolated by the transformer to drive each FET of the modulation board. At this time, the modulation board is connected with a high-voltage power supply and sent to the anode of the microwave triode, and the cathode electrons of the microwave triode begin to emit, and the microwave triode amplifies the low-power high-frequency signal sent to the input end into a high-power high-frequency signal. At the end of the pulse, the cutoff pulse generated by the preprocessor triggers the cutoff plate, and the distributed capacitance of the microwave triode is released after the cutoff plate is turned on, so a good pulse trailing edge can be obtained.
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