1 Exercise 7 The Power Supply

2 The Power Supply.

3 Power Supply Input Voltage 100 to Hz 100 to Hz 200 to 50 Hz 200 to 50 Hz

4 Motherboard Form Factors AT-Type AT-Type ATX-Type ATX-Type

5 AT Motherboard 12” 13.5”

6 ATX Motherboard 9.6 ” 12 ”

7 AT Power Distribution

8 Power Supply Output Voltages AT-Type +5 Volts +5 Volts +12 Volts +12 Volts -12 Volts -12 Volts -5 Volts -5 Volts

9 Power Connector

10 Edge View of Motherboard.

11 Voltage Regulator

12 P9 P8 Black Wires Black Wires Motherboard Power Connectors

P9P8 Back Probing P8 and P9 13

14 Some connectors are held in place by a latch. Latch

P9 Ground + 5V - 5V 15

P8 - 12V + 12V Ground + 5V Power Good 16

17 The Power Good Signal +5 Volt signal generated by the power supply. +5 Volt signal generated by the power supply. It indicates that the power supply has passed its self test and that its output voltages have stabilized. It indicates that the power supply has passed its self test and that its output voltages have stabilized. Usually occurs within first 0.5 seconds. Usually occurs within first 0.5 seconds. Prevents the system from running under bad or unstable power conditions. Prevents the system from running under bad or unstable power conditions.

18 Large Molex Connector

+5V +12V Ground 4-Pin Molex Connector 19

20 Berg Connector

+5V +12V Ground 4-Pin Berg Connector 21

Grasp the connector by the shell… Never by the leads. 22

23 ATX Power Distribution

24 Power Supply Output Voltages ATX-Type +5 Volts +5 Volts +12 Volts +12 Volts -12 Volts -12 Volts -5 Volts -5 Volts +3.3 Volts +3.3 Volts

25 ATX Motherboard Power Connector

26 Power Connector Power Connector

27 Replacing the Power Supply

Disconnect the AC Power Cord. 28

On-Off Switch On-Off Switch 29

Power to CD-ROM Drive Power to CD-ROM Drive 30

Power to Hard Drive Power to Hard Drive 31

Power to Floppy Drive Power to Floppy Drive 32

Power to MPU Fan Power to MPU Fan 33

Power to Motherboard Power to Motherboard 34

The Power Supply is held in place by four screws. The Power Supply is held in place by four screws. 35

Power Supply Power Supply 36

Power Supply Shelf Power Supply Shelf 37

38 Reinstall the power supply.