Complete CompTIA A+ Guide to PCs: Disassembly and Power

This chapter is from the book

Complete CompTIA A+ Guide to PCs, 6th Edition

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This chapter is from the book

This chapter is from the book 

Complete CompTIA A+ Guide to PCs, 6th Edition

Learn More Buy

Exercises

Lab 4.1 Performing Maintenance on an Antistatic Wrist Strap

Objective: To understand how to care for and properly use an antistatic wrist strap

Parts: Antistatic wrist strap

Computer chassis

Multimeter

Note: Electrostatic discharge (ESD) has great potential to harm the electronic components inside a computer. Given this fact, it is vitally important that you practice proper ESD precautions when working inside a computer case. One tool you can use to prevent ESD is an antistatic wrist strap. This tool channels any static electricity from your body to the computer’s chassis, where it is dissipated safely.

Procedure: Complete the following procedure and answer the accompanying questions.

1. Examine the wrist strap for any obvious defects such as worn or broken straps, loose grounding lead attachments, dirt or grease buildup, and so on.
2. If necessary, remove any dirt or grease buildup from the wrist strap, paying close attention to the electrical contact points such as the wrist contact point, the ground lead attachment point, and the computer chassis attachment clip. Use denatured alcohol to clean these contact points.
3. If possible, use a multimeter to check continuity between the wrist contact point and the computer chassis attachment clip. A reading of zero ohms of resistance indicates a good electrical pathway.

   How many volts of static electricity does it take to harm a computer’s electrical components?

4. Adjust the wrist strap so it fits snugly yet comfortably around your wrist. Ensure that the wrist contact is in direct contact with your skin, with no clothing, hair, etc., being in the way.
5. Attach the ground lead to the wrist strap and ensure it snaps securely into place.
6. Attach the computer chassis attachment clip to a clean metal attachment point on the computer chassis.
7. Any static electricity generated or attracted by your body will now be channeled through the antistatic wrist strap to the computer chassis, where it will be safely dissipated.

   How many volts will an ESD be before you will feel anything?

   Should you use an antistatic wrist strap when working inside a monitor?

Instructor initials: _____________

Lab 4.2 Computer Disassembly/Reassembly

Objective: To disassemble and reassemble a computer correctly

Parts: A computer to disassemble

A tool kit

An antistatic wrist strap (if possible)

Note: Observe proper ESD handling procedures when disassembling and reassembling a computer.

Procedure: Complete the following procedure and answer the accompanying questions.

1. Gather the proper tools needed to disassemble the computer.
2. Clear as much workspace as possible around the computer.
3. Power on the computer.

   Why is it important to power on the computer before you begin?

External Cables

4. Turn off the computer and all peripherals. Remove the power cable from the wall outlet and then remove the power cord from the computer.
5. Note where the monitor cable plugs into the back of the computer. Disconnect the monitor including the power cord and move it to a safe place. Take appropriate notes.
6. Remove all external cables from the back of the computer. Take notes on the location of each cable. Move the peripheral devices to a safe place.

   Did the mouse cable connect to a PS/2 or USB port?

Computer Case Removal

7. If possible, remove the computer case. This is usually the hardest step in disassembly if the computer is one that has not been seen before. Diagram the screw locations. Keep the cover screws separate from other screws. An egg carton or a container with small compartments makes an excellent screw holder. Label each compartment and reuse the container. Otherwise, open the case as directed by the manufacturer.

Adapter Placement

8. Make notes or draw the placement of each adapter in the expansion slots.
9. On your notes, draw the internal cable connections before removing any adapters or cables from the computer. Make notes regarding how and where the cable connects to the adapter. Do not forget to include cables that connect to the motherboard or to the computer case.

   List some ways to determine the correct orientation for an adapter or cable.

Internal Cable Removal

10. Remove all internal cables. WARNING: Do not pull on a cable; use the pull tab, if available, or use the cable connector to pull out the cable. Some cables have connectors with locking tabs. Release the locking tabs before you disconnect the cable. Make appropriate notes regarding the cable connections. Some students find that labeling cables and the associated connectors makes reassembly easier, but good notes usually suffice.

Adapter Removal

11. Start with the left side of the computer (facing the front of the computer) and locate the leftmost adapter.
12. Write down any jumpers or switch settings for this adapter. This step may need to be performed after you remove the board from the computer if the settings are inaccessible.
13. If applicable, remove the screw or retaining bracket that holds the adapter to the case. Place the screw in a separate, secure location away from the other screws already removed. Make notes about where the screw goes or any other notes that will help you when reassembling the computer.
14. Remove the adapter from the computer.

    Why must you be careful not to touch the gold contacts at the bottom of each adapter?

15. Remove the remaining adapters in the system by repeating Steps 12–15. Take notes regarding screw locations, jumpers, switches, and so forth for each adapter.

Drives

16. Remove all power connections to drives, such as hard drives, floppy drives, CD/DVD/BD drives, and so on. Note the placement of each drive and each cable, as well as any reminders needed for reassembly.
17. Remove any screws holding the drives in place. Make notes about where the screws go. Keep these screws separate from any previously removed screws.
18. Remove all drives.

    Why must you be careful when handling a mechanical hard drive?

    What would you do differently when handling an SSD than a SATA hard drive?

Power Supply

19. Before doing this step, ensure that the power cord is removed from the wall outlet and the computer. Remove the connectors that connect the power supply to the motherboard.
20. Take very good notes here so you will be able to insert the connectors correctly when reassembling.
21. Remove the power supply.

    What is the purpose of the power supply?

Motherboard

22. Make note of any motherboard switches or jumpers and indicate whether the switch position is on or off.

    What is the importance of documenting switches and jumpers on the motherboard?

23. Remove any remaining connectors except those that connect a battery to the motherboard. Take appropriate notes.
24. Remove any screws that hold the motherboard to the case. Place these screws in a different location from the other screws removed from the system. Write any notes pertaining to the motherboard screws. Look for retaining clips or tabs that hold the motherboard into the case.
25. Remove the motherboard. Make notes pertaining to the motherboard removal. The computer case should be empty after you complete this step.

    Instructor initials: _____________

Reassembly

26. Reassemble the computer by reversing the steps for disassembly. Pay particular attention to cable orientation when reinstalling cables. Before reconnecting a cable, ensure that the cable and the connectors are correctly oriented and aligned before pushing the cable firmly in place. Refer to your notes. The first step is to install the motherboard in the computer case and reconnect all motherboard connections and screws.
27. Install the power supply by attaching all screws that hold the power supply in the case. Reattach the power connectors to the motherboard. Refer to your notes.
28. Install all drives by attaching screws, cables, and power connectors. Refer to your notes. Attach any cables that connect the drive to the motherboard.
29. Install all adapters. Attach all cables from the adapter to the connecting device. Replace any retaining clips or screws that hold adapters in place. Refer to your previous notes and diagrams.
30. Connect any external connectors to the computer. Refer to previously made notes, when necessary.
31. Replace the computer cover. Ensure that slot covers are replaced and that the drives and the front cover are aligned properly. Ensure that all covers are installed properly.
32. Reinstall the computer power cable.
33. Once the computer is reassembled, power on all external peripherals and the computer. A chassis intrusion error message may appear. This is just an indication that the cover was removed.

    Did the computer power on with POST error codes? If so, recheck all diagrams, switches, and cabling. Also, check a similar computer model that still works to see if you made a diagramming error. A chapter on logical troubleshooting comes next in the book. However, at this point in the course, the most likely problem is with a cable connection or with an adapter not seated properly in its socket.

    Instructor initials: ______________

Lab 4.3 Amps and Wattage

Objective: To determine the correct capacity and wattage of a power supply

Parts: Power supply

Internet access (as needed)

Procedure: Complete the following procedure and answer the accompanying questions.

1. Locate the documentation stenciled on the power supply, if possible.

   Can you determine from the documentation how many amps of current the power supply is rated for at 5 volts? If not, proceed to Optional Step 2.

2. Optional: Use the Internet to find the power supply’s documentation on the manufacturer’s website. Use the information you find to answer the remaining questions.

   How many amps is the power supply rated for at 5 volts?

   How many amps is the power supply rated for at 12 volts?

   How many +12V rails does the power supply have?

   What is the maximum rated output power of the power supply in watts?

   Instructor initials: _____________

Lab 4.4 Continuity Check

Objective: To perform a continuity check on a cable and find any broken wires

Parts: Multimeter

Cable and pin-out diagram

Procedure: Complete the following procedure and answer the accompanying questions.

1. Obtain a meter, cable, and pin-out diagram from your instructor.
2. Set the meter to ohms.
3. Power on the meter.
4. Lay the cable horizontally in front of you. The connector on the left is referred to as Connector A. The connector on the right is referred to as Connector B.
5. Determine the number of pins on the cable connector. On a separate sheet of paper, write numbers vertically down the left side of the paper, similar to the numbering used in Lab 4.5. There should be a number for each connector pin. At the top of the numbers write Connector A as the heading. Create a corresponding set of identical numbers vertically on the right side of the paper.
6. Check the continuity of each wire. Document your findings by placing a check mark beside each pin number that has a good continuity check.

   What meter setting did you use to check continuity, and what meter symbol is used for this setting?

7. Power off the meter and return all supplies to the instructor.

   Instructor initials: _____________

Lab 4.5 Pin-Out Diagramming

Objective: To draw a pin-out diagram using a working cable

Parts: Multimeter

Good cable

Procedure: Complete the following procedure and perform the accompanying activities.

1. Obtain a meter and a good cable from your instructor.
2. Set the meter to ohms.

   Instructor initials: _____________

3. Power on the meter.
4. Lay the cable horizontally in front of you. The connector on the left is referred to as Connector A. The connector on the right is referred to as Connector B.
5. Touch one meter lead to Connector A’s pin 1. Touch the other meter lead to every Connector B pin. Notice when the meter shows zero resistance, indicating a connection. Using the table that follows, draw a line from Connector A’s pin 1 to any Connector B pins that show zero resistance. Add more pin numbers as needed to the table or use a separate piece of paper. Remember that all pins do not have to be used in the connector. There are no review questions; however, there is a connector table that contains connection lines. The lines will be cable dependent.

   Connector A	Connector B
   1	1
   2	2
   3	3
   4	4
   5	5
   6	6
   7	7
   8	8
   9	9
   10	10
   11	11
   12	12
   13	13
   14	14
   15	15
   16	16
   17	17
   18	18
   19	19
   20	20

6. Power off the meter.

   Instructor initials: _____________

7. Return all supplies to the instructor.

Lab 4.6 Fuse Check

Objective: To determine if a fuse is good

Parts: Multimeter

Fuse

Procedure: Complete the following procedure and answer the accompanying questions.

1. Obtain a meter and a fuse from your instructor.
2. Look at the fuse and determine its amp rating.

   What is the amperage rating of the fuse?

3. Set the meter to ohms.

   Instructor initials: _____________

4. Power on the meter.
5. Connect one meter lead to one end of the fuse. Connect the other meter lead to the opposite end.
6. Look at the resistance reading on the meter.

   What is the resistance reading?

   Is the fuse good?

7. Power off the meter.

   Instructor initials:_____________

8. Return all materials to the instructor.

Lab 4.7 Using a Multimeter

Objective: To check voltage and resistance levels using a multimeter

Parts: Multimeter

AA, AAA, C, D, or 9-volt battery

Extended paperclip or wire

Caution: Keep both hands on the behind the protective rings on the meter handles. See Figures 4.16 and 4.17.

Procedure: Complete the following procedure and perform the accompanying activities.

1. All voltage inside the computer is DC voltage (except for some parts inside the power supply, of course). Learning how to measure DC voltage is important for a technician. The best place to start is with a battery. Obtain a battery. Look carefully at the battery and determine where the positive end or connector is located (usually has a + (plus) symbol nearby) and where the negative end or connector is located.

   Why is it important to locate positive and negative on a battery?

2. Look carefully at the battery and determine the voltage rating. Document your findings.

   DC voltage:

3. Place the battery on a flat surface. If the battery is an AA, AAA, C, or D battery, place the battery so that the positive side (the side with a nodule) pointing toward your right side. If the battery is a 9-volt battery, place the battery so that the connectors are facing you and the positive connector (the smaller connector) is on your right side.
4. If the meter has leads that attach, attach the black meter lead to the appropriate port colored as a black port or has the COM labeling. Attach the red meter lead to the positive or port marked with a plus sign ( + ).
5. Turn on the meter. Set the meter so that it is measuring VDC (DC voltage). This may involve manually rotating a dial and/or pushing a button. Note that some meters can autodetect the setting, but most involve configuration.

   Document what you did to configure the meter for VDC.

   What indication, if any, did the meter show in the meter window that VDC is being measured?

6. Hold the meter leads so that the black lead is in your left hand and the right lead is in your right hand. Ensure your hands are behind the protective ring on the meter handle. Refer to Figure 4.16 if you are unsure.
7. Place the black meter lead to the negative side (left side or left connector). Also touch the red meter lead to the positive side (right side or right connector) of the battery. Make a note of the meter reading.

   DC volts:

   Based on your findings, is the battery good (usable in an electronic device)?

8. Now reverse the meter leads—place the black lead to the positive side and the red lead to the negative side. Record your findings.

   DC volts:

   What was different from the original meter reading?

9. Perform this voltage check on any other batteries given to you by the instructor or lab assistant.
10. Straighten a paperclip or obtain a wire. Place the paperclip or wire on a flat surface.
11. Change the meter so that it reads ohms. This is normally shown by the omega symbol (Ω).

    While having the meter leads up in the air (not touching each other), what does the meter display?

12. Touch the meter leads together to make a complete circuit or path.

    What does the meter display now?

13. Touch one meter lead to one end of the paperclip or wire, and touch the other meter lead to the opposite paperclip or wire end. Sometimes it is easier to just lay the meter lead on top of the wire close to the end.

    What is the meter reading?

14. Some meters have the ability to make a sound when a wire is good. This is frequently shown on your meter as a sound wave (). If your meter has this ability, configure the meter and redo the test. You can see how much easier this would be than trying to hold your meter leads straight and watch the meter.

    Instructor initials: ______________

15. Power off the meter. Disconnect the leads as necessary. Return all parts to the appropriate location.

Lab 4.8 Wall Outlet and Power Cord AC Voltage Check

Objective: To check the voltage from a wall outlet and through a power cord

Parts: Multimeter

Computer power cord

Caution: Exercise extreme caution when working with AC voltages!

Procedure: Complete the following procedure and perform the accompanying activities.

1. Set the multimeter to AC VOLTAGE (refer to the meter’s manual if you are unsure about this setting). Important: Using a current or resistance setting could destroy the meter.
2. Power on the multimeter. Locate an AC power outlet. Refer to Figure 4.38 for the power connections.
   

   Figure 4.38. AC outlet

3. Insert the meter’s black lead into the round (Ground) AC outlet plug.
4. Insert the meter’s red lead into the smaller flat (Hot) AC outlet plug. The meter reading should be around 120 volts. Use Table 4.9 to record the reading.

   Table 4.9. Wall outlet AC checks

   Connections	Expected voltage	Actual voltage
   GND to hot	120VAC
   GND to neutral	0VAC
   Hot to neutral	120VAC

5. Move the meter’s red lead into the larger flat (Neutral) AC outlet plug. The meter reading should be 0 volts. Use Table 4.9 to record the reading.
6. Remove both leads from the wall outlet.
7. Insert the meter’s black lead into the smaller flat (hot) AC outlet plug.
8. Insert the meter’s red lead into the larger flat (neutral) AC outlet plug. The meter reading should be around 120 volts. Use Table 4.9 to record the reading.
9. Plug the computer power cord into the AC wall outlet that was checked using Steps 3 through 8.
10. Verify the other end of the power cord is not plugged into the computer.
11. Perform the same checks you performed in Steps 3 through 8, except this time check the power cord end that plugs into the computer. Use Table 4.10 to record the reading.

    Table 4.10. Power cord AC checks

    Connections	Expected voltage	Actual voltage
    GND to hot	120VAC
    GND to neutral	0VAC
    Hot to neutral	120VAC

12. If the voltage through the power cord is correct, power off the meter. Notify the instructor of any incorrect voltages.

    Instructor initials: _____________

Lab 4.9 Device DC Voltage Check

Objective: To check the power supply voltages sent to various devices

Parts: Multimeter

Computer

Procedure: Complete the following procedure and perform the accompanying activities.

1. Set the multimeter to DC VOLTAGE (refer to the meter’s manual if unsure about the setting).
2. Power on the multimeter.
3. Power off the computer.
4. Remove the computer case.
5. Locate a Molex or Berg power connector. If one is not available, disconnect a power connector from a device.
6. Power on the computer.
7. Check the +5 volt DC output from the power supply by placing the meter’s black lead in (if the connector is a Molex) or on (if the connector is a Berg) one of the grounds* (a black wire). Place the meter’s red lead on the +5 volt wire (normally a red wire) in or on the connector. Consult Figure 4.39 for the layout of the Molex and Berg power supply connections. Figure 4.39 also contains a table with the acceptable voltage levels.

   ^*Use and check both ground connections (black wires going into the connector); do not check all the voltages using only one ground connection.

   

   Figure 4.39. Molex and Berg power connectors

8. Write the voltage level found for the +5 volt wire in Table 4.11.

   Table 4.11. +5 volt check

   Voltage being checked	Voltage found
   +5 volts

9. Check the +12 volt DC output by placing the meter’s black lead in (if the connector is a Molex) or on (if the connector is a Berg) one of the grounds. Place the meter’s red lead on the +12 volt wire in or on the connector. See Figure 4.39 for the layout of the Molex and Berg power supply connections. The figure also contains a table with acceptable voltage levels. Write the voltage level found for the +12 volt wire in Table 4.12.

   Table 4.12. +12 volt check

   Voltage being checked	Voltage found
   +12 volts

10. Notify the instructor of any voltages out of the acceptable range.
11. Power off the meter.

    Instructor initials: _____________

12. Power off the computer.

Lab 4.10 Windows XP Power Options

Objective: To be able to control power options via BIOS and Windows XP

Parts: Computer with Windows XP loaded

Procedure: Complete the following procedure and answer the accompanying questions.

1. Power on the computer and ensure it boots properly before the exercise begins.
2. Reboot the computer and access BIOS Setup.

   List the BIOS options related to power management.

   Can ACPI be disabled via BIOS?

3. Exit the BIOS setup program without saving any settings. Boot to Windows XP.
4. From the Start button > access Control Panel > Classic view > and the Power Options Control Panel.

   On the Power Schemes tab, what is the current setting used?

   Using the Power Schemes drop-down menu, list the power schemes available.

   What is the current setting for the monitor power scheme?

   What is the current setting for the hard drive power scheme?

   What is the current setting for the system standby?

   What is the maximum amount of time the monitor can be on and then be shut off by the operating system?

5. Select the Advanced tab.

   Describe the power savings icon shown on this window.

   What options are available for the power button?

6. Select the Hibernate tab.

   How much disk space is required for hibernation?

7. Click Cancel.

Lab 4.11 Windows Vista/7 Power Options

Objective: To be able to control power options via BIOS and Windows Vista/7

Parts: Computer with Windows Vista or 7 loaded

Procedure:

1. Power on the computer and ensure it boots properly before the exercise begins.
2. Reboot the computer and access BIOS Setup.

   List the BIOS options related to power management.

   Can ACPI be disabled via BIOS?

3. Exit the BIOS Setup program without saving any settings. Boot to Windows Vista/7.
4. Access the current power settings by using the Start > Control Panel > System and Maintenance (Vista)/System and Security (7) > Power Options.

   What power plan is currently configured?

5. Select the Create a power plan link on the left. Type a unique name in the Plan name textbox. Click Next.
6. Use the Turn off the display drop-down menu to select a time. Use the Put the computer to sleep drop-down menu to select a time for the computer to go into reduced power mode. Note that on a laptop computer there will be two columns of choices: On battery and Plugged in.

   What global ACPI state do you think this would assign? Look back through the chapter to review.

7. Click the Create button. Notice that your new plan appears in the list of preferred plans. Also notice that the Show additional plans reveal arrow might be in the center of the window on the right if someone has hidden the additional plans. Click on Show additional plans, and other plans are revealed.
8. Click on the Change plan settings link under or beside the plan you just created. Select the Change advanced power settings link.

   List at least three devices for which you can have power controlled through this control panel.

9. Expand the USB settings, if possible, and the USB selective suspend setting.

   What is the current setting?

10. Expand the Processor power management setting, if possible.

    What is the minimum processor state?

    What is the maximum processor state?

11. Expand the Multimedia settings, if possible.

    What setting(s) is configured with this option?

12. Click the Cancel button to return to the Change settings window. Click the Cancel button again. Show the instructor or lab assistant your settings.

    Instructor initials: __________

13. To delete a power plan you created (the default ones cannot be deleted), select the radio button for the original power plan. Refer to Step 4, if necessary. Under the plan you created, select the Change settings for the plan link. Select the Delete this plan link and click OK. The plan should be removed from the power options list. Show the instructor or lab assistant that the plan has been deleted.

    Instructor initials: __________