1. Copyright © 2007 Heathkit Company, Inc. All Rights Reserved PC Fundamentals Presentation 2 – The Power Supply

2. 2 Objectives At the end of this presentation, you will be able to:

3. 3 Identify the input and output voltages of the power supply. Demonstrate the proper method to measure the DC output voltages of the power supply. Explain how power is distributed throughout the computer. Demonstrate the proper method to remove and replace the power supply in the computer. Compute the power consumption of the PC.

4. 4 The Power Supply.

5. 5 The Power Supply FAN AC Receptacle On/Off Switch

6. 6 Power Supply Input Voltage 100 to 125 VAC @ 60 Hz 200 to 250VAC @ 50 Hz

7. 7 Motherboard Form Factors AT-Type ATX-Type

8. 8 AT Motherboard 12” 13.5”

9. 9 ATX Motherboard 9.6 ” 12 ”

10. 10 ATX Mother- board

11. ATX Power Distribution

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

13. 13 ATX Motherboard Power Connector

14. 14 20-Pin Power Connector 20-Pin Power Connector

15. 15 24-Pin Power Connector 24-Pin Power Connector

16. 16 2 X 10 ATX Connector 2 X 2 Connector

17. 17

18. Edge View of Motherboard.

19. 19 A Second 2 X 2 Motherboard Power Connector Supplies Processor Core Power (+12 Volts)

20. 20

21. 21

22. AT Power Distribution

23. 23 Power Supply Output Voltages AT-Type +5 Volts +12 Volts -12 Volts -5 Volts

24. 24 Power Connector

25. 25 P9 P8 Black Wires Black Wires Motherboard Power Connectors

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

27. 27 P9 Ground + 5V - 5V

28. 28 P8 - 12V + 12V Ground + 5V Power Good

29. 29 The Power Good Signal +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. Usually occurs within first 0.5 seconds. Prevents the system from running under bad or unstable power conditions.

30. Large Molex Connector

31. 31 +5V +12V Ground 4-Pin Molex Connector

32. Berg Connector

33. 33 +5V +12V Ground 4-Pin Berg Connector

34. 34 Grasp the connector by the shell… Never by the leads.

35. 35 Replacing the Power Supply

36. 36 Disconnect the AC Power Cord.

37. 37 On-Off Switch On-Off Switch

38. 38

39. 39 Power to Motherboard Power to Motherboard

40. 40 The Power Supply is held in place by four screws. The Power Supply is held in place by four screws.

41. 41 Power Supply Power Supply

42. 42 Reinstall the power supply.

43. Copyright © 2007 Heathkit Company, Inc. All Rights Reserved PC Fundamentals End