Lab 9 Multimeter

Home Up Objectives Sat AM Assignments Sound & Multi-Media Hard Drive Info Hard Dr Lab #1 Slides on Current Power Supply Notes Lab 10 Power S Lab11 Diags PC R II Sat Grades PC Repair II Labs Lab1 CDROM Lab 2 FDISK & P M Lab3 Upgrade HD Lab 4, Drive Image. Lab 5 Floppy Dr Lab 6 Memory Lab 7 Sound Card Lab 8 PC Prices Lab 9 Multimeter

Lab 9-Using a Multimeter

A multimeter is a voltmeter or an ammeter that can also measure resistance in ohms or as continuity (presence of a complete circuit), depending on a switch setting

•Note: always measure voltage and amps with electricity ON

•Measure resistance and continuity with electricity OFF

Autorange meter •Senses quantity of input and sets the range accordingly

Otherwise you must change ranges on the meter to increase the accuracy, and to keep from damaging it.Too much current can blow it up!

 

  1. Attach Leads (sometimes attach to different places depending on usage)
  2. Turn Meter On
  3. Set to right usage: Volts, Ohms (Resistance or Continuity), or Current (amps or milliamps) If you do not have autorange on your meter you must set it manually to the largest value and then work down.!
  4. Attach probes to hot leads: plus to plus and minus to minus for DC! Or +Volts to + and – to ground, - Volts to – and + to ground!
  5. Take reading.
  6. When done turn meter off!

Measuring Voltage Output to an AT System Board

Measure voltage of each circuit supported by power supply

Meter Position  
AT Pin Voltages  

 

Measuring Voltage Output to an ATX System Board

 

 

1.      Try to determine what type of board and power supply connector you have from the above graphics.

  1. Set up a table and measure the voltage of each pin in the motherboard connector.
  2. Record it in the appropriate table below:
  3. Does it match what should be there?
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  4. Does this indicate a problem with the power supply?
  5. Measure the voltage applied to a small (3.5 inch) drive connector
    What is it ___________________________________________________
  6. Repeat for a 5 inch drive connector.
    What is it ___________________________________________________
  7. Turn off the meter when you are done and return it to the cabinet.
  8. Replace the case on your PC,
  9. Test the PC to see if it still works
  10. Shut down the PC, turn off the monitor.

ATX Style Motherboard Power Connector

 

 

 

 

 

Connecter

1

2

3

4

5

6

7

8

9

10

Voltage

 

 

 

 

 

 

 

 

 

 

Connecter

11

12

13

14

15

16

17

18

19

20

Voltage

 

 

 

 

 

 

 

 

 

 

 

AT Style Motherboard Power Connector

 

 

Connecter

1

2

3

4

5

6

Voltage

 

 

 

 

 

 

Connecter

7

8

9

10

11

12

Voltage

 

 

 

 

 

 

 

What conclusions can you draw as a result of this lab?

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    ©2000

 

Home Objectives Sat AM Assignments Sound & Multi-Media Hard Drive Info Hard Dr Lab #1 Slides on Current Power Supply Notes Lab 10 Power S Lab11 Diags PC R II Sat Grades PC Repair II Labs Lab1 CDROM Lab 2 FDISK & P M Lab3 Upgrade HD Lab 4, Drive Image. Lab 5 Floppy Dr Lab 6 Memory Lab 7 Sound Card Lab 8 PC Prices Lab 9 Multimeter