SMPS IS Switch Mode Power Supply. It is mainly used to convert AC to DC.SMPS are of two types AT and ATX.In AT SMPS system we have to manually Shutdown the computer. After giving Shutdown command “It is now safe to turn off your system” message appears then press the power button to shut down. In ATX SMPS shutdown is automatic, that is just give the Shutdown command. Now we are using ATX Smps.
TO CHECK WETHER SMPS IS WORKING OR NOT
Take a small piece of wire and connect one end in GREEN wire port and other in the BLACK. Switch ON the supply if the fan in the smps is working the smps is good. If not open the cover and check whether the Capacitors inside the Smps is bulged on the top. If bulged replace the capacitor with the same value of the earlier.Check the voltages with a multimeter.
SMPS CONNECTORS
Amphenol connector gives power supply to Mother Board
Mole x gives power supply to IDE drives
Mini Molex gives power supply to floppy drive.
SMPS WIRES IN ATX
WIRE VOLTAGE FUNCTION
Black 0 Ground
Blue -12 Serial Data
Brown/Violet +3.3 Sensor
Gray +5 Power good supply
Green +5 Power supply on/off
Orange +3.3 D Ram Refreshing
Purple +5 Stored by voltage
White -5 Refreshing Ram
Yellow +12 Motor Rotation
Red +5 Logic circuit
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