ZC State Polytechnic College  
  Module 1 06/09/2023 3:21pm (UTC)










Title:   Disassembling and Reassembling the System Unit and Identifying Internal Components and Connections


Time Frame: 3 hours


Learning Objectives

In this module, you will locate, remove, and describe the various internal components and connectors of a standard PC system.


At the end of this module, you’ll be able to

Ø  Remove all major components of a PC

Ø  Recognize all major components inside a PC

Ø  Name the function of each component

Ø  Define the relationship of internal components to external connections


Learning Content




You’re now going to walk through the complete disassembly of the system unit. Try to do this in an orderly sequence, but, depending on the configuration of the computer you are disassembling, you may have to perform one or two of the steps out of sequence. For example, you may have to remove a CD or DVD media drive before you can gain access to remove the power supply. When you’re on the job, you’ll encounter different models of personal computers manufactured by different companies. Along with learning the slightly different methods of component removal and installation, you should be able to identify the major internal parts of the PC system, regardless of the manufacturer. This lab exercise will help you practice doing that.


Ready, Set, GO!





Shut off the power to your system and unplug the power cord from your PC and from the wall socket before doing the following exercise.


Step 1 Disconnect all the external cables (monitor, keyboard, mouse, printer, etc.) from the PC

you are going to use, and place the PC on a fl at, stable surface (preferably on an anti-static mat) where you can sit or stand comfortably to inspect the insides.


Step 2 Use proper anti-static procedures while opening the case and during this entire exercise.

Using whichever method applies to your case (thumbscrews, Phillips-head screws, locking tabs), remove the cover of your system unit and then lie the system down so that the open side faces the ceiling. Look inside your system case. What do you see? To begin with, you’ll see lots of cables and wires. Some appear to be single-colored wires, while others seem to be multiple gray-colored wires in the shape of wide ribbons. Most colored wires originate at the power supply and end at the various devices to supply the needed direct current (DC) power to run the PC. The wide ribbon cables attach various components and are used to transfer data. These are sometimes referred to as logic cables or data cables. See if you can locate in your system case the major components labeled in Figure 1-1. You may have to move some of the fan shrouds, wires, and cables in order to find them—especially components on the motherboard—but remember your anti-static procedures and be gentle. Sometimes the slightest bump is enough to unseat a connection.



Step 4 To start, you’ll need to clear the way—a bit like peeling an onion, layer by layer—by

removing the easily accessible components and cables first. Look inside the PC and find the expansion slots. How many total expansion cards can be plugged into your system? Some of the expansion slots may have cards in them. These may be modem cards, sound cards, network cards, or video cards. Since expansion cards are designed to “expand” the capability of the computer system, they are designed to be installed after the system unit is assembled. For this reason, the expansion cards are a great place to begin your disassembly. Look at the expansion cards installed in your PC, and then look at the external connectors on each. Can you match the cable to the expansion card?


Remove all installed expansion cards from your system unit. Place each card into an anti-static

bag to protect it from ESD damage.


Step 5 If the computer you are disassembling is only a few years old, it will probably have multiple fan shrouds to make sure the airflow is getting to the main components to keep them cool. Remove any fan shrouds from your system unit and place them out of the way on your workspace.



After removing each item—especially the bulky items, such as fan shrouds, wiring, and cables—it would be good to take a few more notes or pictures. Now that you have a better view of the components underneath, you will be able to consult these notes or pictures during reassembly.



You can complete the next three steps in the order written or out of order, whichever works best for your system unit. You’ll be removing the power supply wires, the power supply, and the data cables from the components and motherboard. If one of the data cables is in the way of one of the wires, it’s okay to remove the data cable first. Please remember to keep good records (notes or photos) of your configuration.


Step 6 Locate the power supply, which is a large silver box in one corner of the system unit case. Trace the colored wires leading out of it. Remember to be gentle! Find the power plug(s) for the motherboard. If you have a newer PC, it will probably look like the one in Figure 1-2. If you have an older PC, you might see two power connectors installed side by side.


Find the power connectors for the floppy, CD-ROM (if applicable), and hard drives. Do they

look like one of the connectors in Figure 1-3? They should!



Remove all of the power connectors from the motherboard and all data drives. Place them to the side as best as you can until you remove the power supply itself.


Step 7 If possible, remove the power supply at this point. If there are still many cables and components in the way, you can perform this step later in the lab.


Step 8 Now look at the floppy drive, which should be attached to a fl at ribbon cable. (Don’t worry if your system doesn’t have a floppy drive—just move on and explore your other data drives.) Trace the ribbon cable to the motherboard. Do the same for all your other data drives: hard drives, CD media drives, and DVD media drives, as applicable. These ribbon cables are about one and a half inches wide, and they are normally gray with a colored stripe on one side. The stripe—usually red—orients the cable properly to the connections on the motherboard and the floppy drive. The cable to the floppy drive has 34 wires (conductors) and, in most cases, has a twist in the center. Its position relative to this seven-wire twist determines whether a floppy drive is the primary (or A:) drive for the system (attached to the connector at the end of the cable past the twist) or the secondary (B:) drive for the system (attached to the center connector).



It’s rare to find two floppy drives in a newer system; in fact, floppy drives are going away

completely on most brand-new systems. On systems that do have floppy drives, you will not find a floppy cable at all, though you may still have a 34-pin connector on the motherboard. On systems utilizing only one floppy drive, manufacturers may use a shorter floppy cable with no twist and no second drive connector. The type of ribbon cable that connects the hard drive(s) and CD or DVD media drive to the motherboard has 40 wires and no twist. You may even have the newest cable type, which has


80 conductors to allow for faster transmission speed of the data to and from the hard drives. Both of these cable types still have a colored edge on one side for orientation. Many current systems use much smaller, seven-wire cables for Serial ATA, or SATA, hard drives; these cables have connectors keyed like the letter L.


Step 9 After noting the current state of the ribbon cables, disconnect and reconnect each device’s cable in turn. Practice this a few times. Can you plug a cable in backwards? Try it. Put the cable on the device the wrong way if you can. Older types of cables can be put on incorrectly, but newer cables and connectors have built-in keying to prevent this from happening. Make sure that the cables are properly connected when you’ve finished. Now look at where the ribbon cables connect to the motherboard. Make note of the proper cable orientation. Practice disconnecting and reconnecting the cables at the motherboard. Do you have any problems if you try to plug these cables in backwards? When you feel you have practiced enough, remove the cables and place them safely away from the computer on your work surface. Now would be a great time to make a drawing or take a photograph of the de-cluttered system unit interior.


Step 10 Most modern systems have a set of small wire and cable runs connecting front panel

indicator lights—primarily the power-on and hard drive activity light emitting diodes (LEDs)— and front panel Universal Serial Bus (USB) ports to the motherboard (see Figure 1-4). Look for these individual wire connections (often collectively called case wires), which are usually grouped together near one corner of the motherboard. Make careful note of where each tiny connector plugs in—a photo would be incredibly helpful here—and then disconnect them all and tuck the wires out of the way.


Step 11 Now that all of the wires and cables are removed, you should have plenty of room to

finish up the disassembly. You’re now going to remove all the drives. Drives are usually the most cumbersome to remove due to the drive cages or frames where they’re mounted (see Figure 1-5). Depending on the mounting the manufacturer has used, removing a drive may be as simple as pulling out a sliding mechanism or as complicated as opening up the other side of the system case, removing all the decorative plastic facing, and removing a handful of screws.



Remove the floppy drive, CD-ROM drive, DVD media drive (if present), and the hard drive(s), and set them on your work surface.


Step 12 Look in your PC and find the RAM modules. RAM comes in thin, wafer-like modules, about 3" 5" long by one inch wide. A row of metal contacts running along one of the long edges plugs into a matching socket, which is three to five inches in length, located on the motherboard. Look for a long wafer standing on its edge; often, you’ll find two or more RAM modules lined up in a row.


How many RAM modules do you have? __________________________________


Do you have Dual Inline Memory Modules (DIMMs) or Single Inline Memory Modules

(SIMMs)? ________________________________________________________________


Making sure to follow proper anti-static procedures, remove the SIMMs or DIMMs from their

slots and place them in an anti-static bag for safekeeping.


Step 13 Look in your PC and see if you can locate the CPU. Running CPUs generate a fair amount of heat, so they need their own dedicated cooling mechanisms. Because of this, when you search the motherboard, trying to fi nd the CPU, you’ll generally find it hidden under a fan/heat sink unit. Carefully remove the fan/heat sink unit from the CPU.



Make sure that you fully understand how to remove your particular model of CPU fan before you try it!


If you were able to remove the fan, make a note of the type of CPU chip you have:



If you’re in a computer lab with multiple systems, examine a number of different CPU chips. Note where each CPU is located on the motherboard. Making sure to follow proper anti-static procedures, lift the lever of the Zero Insertion Force (ZIF) socket, remove the CPU, and place it in an anti-static bag for safekeeping.


Step 14 See if you can locate any jumpers or Dual Inline Package (DIP) switches on your motherboard. Resist the temptation to play with them at this point—just make a note of what you find. In particular, look for the identifying labels on the motherboard.


Step 15 Making sure to follow proper anti-static procedures, remove the screws that secure the

motherboard to the chassis or frame of the system case. Place the motherboard in a properly sized anti-static bag, and put it aside. If you have used an area where you can leave the components, wires, cabling, and hardware for a while, you can leave the PC disassembled for later labs. If you really need to clean up the area for now, you can either follow your notes (and lab steps) in reverse order to reassemble the system or find a large box to store the disassembled computer until your next lab session. Don’t worry about the ESD-sensitive components; as long as they are in their anti-static bags, they should be fine.







You have explored and removed nearly all the components of a typical PC system unit. To finish this lab exercise, see if you can identify all of the components in Figure 1-6.


A ___________________________

B ___________________________

C ___________________________

D ___________________________

E ___________________________

F ___________________________

G ___________________________

H ___________________________

I ___________________________

J ___________________________




Lab Materials and Setup


The materials you need for this lab are

- A lab partner, if possible

- At least one PC that isn’t vital to your (or anyone else’s) home or business, not necessarily

     in working order but preferably less than a few years old

- An anti-static wrist strap

- An anti-static mat (optional)

- Twelve anti-static bags of various sizes

- A simple technician’s toolkit

- A plastic cup or box to organize the various screws, nuts, and bolts that you’ll remove

- A clean, well-lighted workspace of about 3’ x 4’ (a kitchen table with some newspaper

    spread about usually makes a fairly decent ad-hoc lab bench)

- A notepad on which to take notes and make sketches of the computer and components

- A digital camera to record the placement, configuration, connections, and connectors

    associated with the components you’ll be removing from the system unit (optional)


Strategies / Alternative Strategies



            Multimedia Presentation




            Actual Performance Test




            CONGRATULATIONS! You have successfully completed this module and you are now ready to proceed on the next module..




            A. Power Supply

B. Processor

C. Modem

D. Audio Card

E. PCI Slot


G. Molex Collector

H. Video Card

I. Hard Disk

J. Battery





1.    Mike Myer’s Guide PC Technician

Copyright © 2007 by The McGraw-Hill Companies.


2.    Managing and Troubleshooting PCs

Second Edition

Copyright © 2007 by The McGraw-Hill Companies.


3.    The Illustrated Dictionary of Electronics

Copyright © 2001 by The McGraw-Hill Companies.


4.    Computer Repair with Diagnostic Flowchart

Copyright © 2004 by Morris Rosenthal Published by Foner Books




As a state institution for both non-degree and degree courses and advanced technological studies, the Zamboanga City State Polytechnic College would have achieved its mandates by providing technically inclined youths in Region IX with all the desired Maritime, Scientific and Technological knowledge and skills for gainful economic pursuit. Furthermore, the College would be able to develop in the youth the ability to critically think, create, act positively and contribute to the full development of the family, community, Region IX and the entire nation.
The Zamboanga City State Polytechnic College shall take the leadership role in the frontiers of Science, Technology, Maritime and Technological-Vocational Education by providing effective and efficient services through professional and technical training and in the conduct of educational researches and technological studies to support its vision and development of the individual person, the family, the community, the region and the entire nation.
In an environment of academic freedom, excellence, and relevance, the Zamboanga City State Polytechnic College brings out the best of what it is to be human and harnesses, catalyzes and develops the constructive and productive use of the full potentials and capabilities of Region IX Filipino men and women into becoming creative, decisive, competitive, critically thinking and acting individuals who contribute to the socio-economic recovery of the nation in general, and the region in particular, making vocational-technical, maritime, science and technological education research extension available to the youths and the adults.
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