CompTIA A+ Complete Study Guide phần 3 potx

126 Chapter 2  Effectively Working with Personal Computer Components Another problem you may encounter is a phantom directory listing. For example, suppose you display the contents of a floppy disk, and then you swap to another floppy disk but the listing stays the same. This is almost always a result of a faulty ribbon cable; a particular wire in the ribbon cable signals when a disk swap has taken place, and when that wire breaks, this error occurs. Identifying Sound Card Problems Sound cards are traditionally one of the most problem-ridden components in a PC. They demand a lot of PC resources and are notorious for being inflexible in their configuration. The most common problems related to sound cards involve resource conflicts (IRQ, DMA, or I/O address). The problem is much less pronounced on PCI than on ISA cards. Luckily, most sound-card vendors are aware of the problems and ship very good diagnostic utilities to help resolve them. Use your PC troubleshooting skills to determine the conflict, and then reconfigure until you find an acceptable set of resources that aren’t in use. Some sound cards aren’t completely Plug and Play compatible. Windows may detect that new hardware has been installed but be unable to identify the new hardware as a working sound card. To fix this problem, run the Setup software that came with the sound card. Identifying CD-ROM/DVD Issues CD-ROM and DVD problems are normally media related. Although compact disc technology is much more reliable than that for floppy disks, it’s not perfect. Another factor to consider is the cleanliness of the disc. On many occasions, if a disc is unreadable, cleaning it with an approved cleaner and a lint-free cleaning towel will fix the problem. If the operating system doesn’t see the drive, start troubleshooting by determining whether the drive is receiving power. If the tray will eject, you can assume there is power to it. Next, check BIOS Setup (for IDE drives) to make sure the drive has been detected. If not, check the master/slave jumper on the drive, and make sure the IDE adapter is set to Auto, CD-ROM, or ATAPI in BIOS Setup. Once inside the case, ensure that the ribbon cable is properly aligned with pin 1 and that both the drive and motherboard ends are securely connected. In order to play movies, a DVD drive must have MPEG decoding capability. This is usually accomplished via an expansion board, but it may be built into the video card or sound card, or it may require a software decoder. If DVD data discs will play but not movies, suspect a problem with the MPEG decoding. If a CD-RW or DVD drive works normally as a regular CD-ROM drive but doesn’t per- form its special capability (doesn’t read DVD discs or doesn’t write to blank CDs), perhaps you need to install software to work with it. For example, with CD-RW drives, unless you’re using an operating system such as Windows XP that supports CD writing, you must install CD-writing software in order to write to CDs. Identifying NIC Issues In general, network interface cards (NICs) are added to a PC via an expansion slot. The most common issue that prevents network connectivity is a bad or unplugged patch cable. 4830c02new.fm Page 126 Thursday, August 23, 2007 5:43 PM Identifying Tools and Diagnostics for PC Components 127 Cleaning crews and the rollers on the bottoms of chairs are the most common threats to a patch cable. In most cases, wall jacks are placed 4 to 10 feet away from the desktop. The patch cables are normally lying exposed under the user’s desk, and from time to time damage is done to the cable, or it’s inadvertently snagged and unplugged. When you troubleshoot a network adapter, start with the most rudimentary explanations first. Make sure the patch cable is tightly plugged in, and then look at the card and see if any lights are on. If there are lights on, use the NIC’s documentation to help troubleshoot. More often than not, shutting down the machine, unplugging the patch and power cables for a moment, and then reattaching them and rebooting the PC will fix an unresponsive NIC. A properly connected NIC should typically have one light illuminated (the link light). If the link light is not illuminated, it indicates a problem with the NIC, the patch cable, or the device the patch cable is connecting to (hub, switch, server, and so on) Other lights that may be illuminated include a speed light, duplex light, and/or activity light. Wake On LAN cards have more problems than standard network cards. In our opinion, this is because they’re always on. In some cases, you’ll be unable to get the card working again unless you unplug the PC’s power supply and reset the card. Identifying BIOS Issues Computer BIOSs don’t go bad; they just become out-of-date. This isn’t necessarily a critical issue—they will continue to support the hardware that came with the box. It does, however, become an issue when the BIOS doesn’t support some component that you would like to install—a larger hard drive, for instance. Most of today’s BIOSs are written to an EEPROM and can be updated through the use of software. Each manufacturer has its own method for accomplishing this. Check out the documentation for complete details. If you make a mistake in the upgrade process, the computer can become unbootable. If this happens, your only option may be to ship the box to a manufacturer-approved service center. Be careful! Identifying Power-Supply Problems Power-supply problems can manifest themselves as a system that doesn’t respond in any way when the power is turned on. When this happens, open the case, remove the power supply, and replace it with a new one. Partial failures, or intermittent power-supply problems, are much less simple. A completely failed power supply gives the same symptoms as a malfunctioning 4830c02new.fm Page 127 Thursday, August 23, 2007 5:43 PM 128 Chapter 2  Effectively Working with Personal Computer Components wall socket, UPS or power strip, a power cord that is not securely seated, or some mother- board shorts (such as those caused by an improperly seated expansion card, memory stick, CPU, and the like), and you want to rule out those items before you replace the power supply and find you still have the same problem as when you started. Be aware that different cases have different types of on/off switches. The process of replacing a power supply is a lot easier if you purchase a replacement with the same mechanism. Never try to repair or disassemble a power supply. There is a high risk of elec- trocution, and the relatively low cost of a new power supply makes working on them something to avoid. Identifying Miscellaneous Problems Some common problems don’t fit well into categories. This section lists some common hard- ware issues you’ll be faced with. Dislodged Chips and Cards The inside of a computer is a harsh environment. The temperature inside the case of some Pentium computers is well over 100° F! When you turn on your computer, it heats up. Turn it off, and it cools down. After several hundred such cycles, some components can’t handle the stress and begin to move out of their sockets. This phenomenon is known as chip creep, and it can be really frustrating. Chip creep can affect any socketed device, including ICs, RAM chips, and expansion cards. The solution to chip creep is simple: Open the case, and reseat the devices. It’s surprising how often this is the solution to phantom problems of all sorts. Another important item worth mentioning is an unresponsive but freshly unboxed PC. With the introduction of the Type II– and Type II–style of processors, the number of dead boxes increased dramatically. In fact, at that time I was leading a 2,000-unit migration for a large financial institution. As with any large migration, time and manpower were in short supply. The average dead PC ratio was about 1 out of every 20. When about 10 DOAs had stacked up, I stayed after work one night to assess the problem. After checking the power supply, RAM, and cables on these integrated systems, an examination of the chip provided me with the fix. These large, top-heavy processors can become dislodged during shipment. Shortly after, manufacturers began using a heavier attachment point for the slot style of pro- cessor, which has helped tremendously. Environmental Problems Computers are like human beings: They have similar tolerances to heat and cold. In general, anything comfortable to us is comfortable to computers. They need lots of clean, moving air to keep them functioning. Dirt, grime, paint, smoke, and other airborne particles can become caked on the inside of the components. This is most common in automotive and manufacturing environments. The contaminants create a film that coats the components, causing them to overheat and/or con- duct electricity on their surface. Blowing out these exposed systems with a can of condensed 4830c02new.fm Page 128 Thursday, August 23, 2007 5:43 PM Performing Preventative Maintenance on Personal Computers 129 air from time to time can prevent damage to the components. While you’re cleaning the com- ponents, be sure to clean any cooling fans in the power supply or on the heat sink. To clean the power supply fan, blow the air from the inside of the case. When you do this, the fan will blow the contaminants out the cooling vents. If you spray from the vents toward the inside of the box, you’ll be blowing the dust and grime inside the case or back into the fan motor. One way to ensure that the environment has the least possible effect on your computer is to always leave the blanks in the empty slots on the back of your box. These pieces of metal are designed to keep dirt, dust, and other foreign matter from the inside of the computer. They also maintain proper airflow within the case to ensure that the computer doesn’t overheat. Performing Preventative Maintenance on Personal Computers This section outlines some preventative maintenance products and procedures. Preventative main- tenance is one of the most overlooked ways to reduce the cost of ownership in any environment. Cleaning a computer system is the most important part of maintaining it. Computer com- ponents get dirty. Dirt reduces their operating efficiency and, ultimately, their life. Cleaning them is definitely important. But cleaning them with the right cleaning compounds is equally important. Using the wrong compounds can leave residue behind that is more harmful than the dirt you’re trying to remove! Most computer cases and monitor cases can be cleaned using mild soap and water on a clean, lint-free cloth. Make sure the power is off before you put anything wet near a computer. Dampen (don’t soak) a cloth with a mild soap solution, and wipe the dirt and dust from the case. Then wipe the moisture from the case with a dry, lint-free cloth. Anything with a plastic or metal case can be cleaned in this manner. Don't drip liquid into any vent holes on equipment. CRTs in particular have vent holes in the top. To clean a monitor screen, use glass cleaner designed specifically for monitors and a soft cloth. Don’t use commercial window cleaner, because the chemicals in it can ruin the antiglare coating on some monitors. To clean a keyboard, use canned air to blow debris out from under keys, and use towelettes designed for use with computers to keep the key tops clean. If you spill anything on a keyboard, you can clean it by soaking it in distilled, demineralized water. The minerals and impurities have been removed from this type of water, so it won’t leave any traces of residue that might interfere with the proper operation of the keyboard after cleaning. Make sure you let the keyboard dry for at least 48 hours before using it. 4830c02new.fm Page 129 Thursday, August 23, 2007 5:43 PM 130 Chapter 2  Effectively Working with Personal Computer Components The electronic connectors of computer equipment, on the other hand, should never touch water. Instead, use a swab moistened in distilled, denatured isopropyl alcohol (also known as electronics cleaner and found in electronics stores) to clean contacts. Doing so will take the oxidation off the copper contacts. A good way to remove dust and dirt from the inside of the computer is to use compressed air. Blow the dust from inside the computer using a stream of compressed air. However, be sure you do this outdoors, so you don’t blow dust all over your work area or yourself. You can also use a vacuum, but it must be designed specifically for electronics—such models don’t generate ESD and have a finer filter than normal. To prevent a computer from becoming dirty in the first place, control its environment. Make sure there is adequate ventilation in the work area and that the dust level isn’t excessive. To avoid ESD, you should maintain 50 to 80 percent humidity in the room where the com- puter is operating. You should visually inspect the computer for signs of distress within it. Discolored areas on the board are often caused by overheating. The overheating can be caused by power surges or overclocking and is an indication that all is not right. One unique challenge when cleaning printers is spilled toner. It sticks to everything and should not be inhaled. Use a vacuum designed specifically for electronics. A normal vacuum’s filter isn’t fine enough to catch all the particles, so the toner may be circulated into the air. If you get toner on your clothes, use a magnet to get it out (toner is half iron). Removable media devices such as floppy and CD drives don’t usually need to be cleaned during preventative maintenance. Clean one only if you’re experiencing problems with it. Cleaning kits sold in computer stores provide the needed supplies. Usually, cleaning a floppy drive involves using a dummy floppy disk made of semi-abrasive material. When you insert the disk in the drive, the drive spins it, and the abrasive action on the read-write head removes any debris. An uninterruptible power supply (UPS) should be checked periodically as part of the pre- ventative maintenance routine to make sure that its battery is operational. Most UPSs have a Test button you can press to simulate a power outage. You will find that batteries wear out over time, and you should replace the battery in the UPS every couple of years in order to keep the UPS dependable. The motherboard contains a battery, as well, which is used to maintain internal settings when power is not provided to the unit. Resembling large watch batteries, these entities tend to have a considerable life, on average, but can lose their charge over time. If you boot a system and find that the date and time and other variables have not been maintained, you will want to change the internal battery. Remember, preventative maintenance is more than just manipulating hardware; it also encompasses running software utilities on a regular basis to keep the file system fit. These utilities can include Disk Defragmenter, ScanDisk, Check Disk, and Disk Cleanup. 4830c02new.fm Page 130 Thursday, August 23, 2007 5:43 PM Summary 131 Summary In this chapter, you finished learning about personal computer components, specifically storage devices, display devices, and input and multimedia devices. In addition, we discussed identifying various problems that can occur, as well as various solutions or approaches to finding a solution. Finally, we walked through troubleshooting the- ory and techniques and concluded by examining some preventative maintenance recommen- dations and issues. Exam Essentials Know how many pins an IDE/PATA/ATA-5/ATA-6 cable has. A cable for use with these technologies has 40 pins. You’re likely to be asked to choose a cable in a scenario question simply by knowing how many pins the drive requires. Know how a controller works in a master/slave environment. When you have a master and a slave, only one of the two controllers controls data transfers. You’re likely to be asked a scenario question that relates to this environment. Know what other devices besides hard drives use IDE interfaces. With the popularity of IDE technology, manufacturers have introduced tape drives and CD-ROMs that use IDE interfaces. Know what can be used to clean computer components. Many types of cleaning solutions can be used to perform these procedures. Be familiar with which option is best for each com- ponent. Which ones can be cleaned with water? Which ones require alcohol? Which ones need canned air? Know why the proper cleaning solutions should be used. Using the wrong cleaning solution can damage components. Along with choosing the right cleaning solution, understand why the improper solutions are inappropriate for a particular component. 4830c02new.fm Page 131 Thursday, August 23, 2007 5:43 PM 132 Chapter 2  Effectively Working with Personal Computer Components Review Questions 1. Which of the following steps is not necessary when replacing a floppy drive? A. Turn off the PC. B. Disconnect the power supply from the drive. C. Disconnect the ribbon cable from the drive. D. Disconnect the audio cable from the drive. 2. When attaching a ribbon cable to a drive, if there is no marking for pin 1, which way should you orient the red stripe? A. Closest to the power supply connector B. Farthest away from the power supply connector C. Facing the top of the drive D. Facing the bottom of the drive 3. To fix a bad power supply in a desktop PC, you should ____________. A. Remove and replace the entire power supply box. B. Disassemble the power supply and replace the coils. C. Disassemble the power supply and replace the capacitors. D. Disassemble the power supply and replace the resistors. 4. How many bits of data does a high-speed serial cable carry simultaneously in a single direction? A. 1 B. 8 C. 32 D. Depends on the cable 5. Which of the following could not be connected to an IDE interface on a typical motherboard? A. ATA-2 B. EIDE C. ATAPI D. All of these could be connected. 6. What do UltraDMA/66 and higher require? A. Cable Select configuration B. An 80-wire cable C. Operating system support D. All of the above 4830c02new.fm Page 132 Thursday, August 23, 2007 5:43 PM Review Questions 133 7. On the primary IDE channel, if a single hard disk is attached, its jumper should be set to ________. A. Slave B. Single if available; otherwise Master C. Master D. Boot 8. Which type of SCSI termination uses voltage regulators inside the terminator? A. Active B. Passive C. High-byte D. All of the above 9. You install a new UltraATA/100 hard disk in an old PC, connecting it directly to the primary IDE on the motherboard. You use the 80-wire ribbon cable that came with it. Performance testing indicates that the new drive is not performing up to UltraATA/100 standards. What could you try next? A. Reformat the hard disk using NTFS 5.0. B. Add an ATA/100-compatible expansion board and connect the drive to it. C. Partition the disk into smaller logical drives. D. Set up the drive in BIOS Setup to use PIO mode 4. 10. Which AT command resets the modem? A. ATH0 B. ATM0 C. ATZ D. ATDT 11. While inspecting a motherboard, you notice a discolored area. What is usually a cause of this? A. Spilled liquid B. Improper manufacture C. Power surge D. Underclocking 12. What does the red stripe on a ribbon cable indicate? A. Pin 16 B. Pin 1 C. The manufacturer’s trademark D. Parity 4830c02new.fm Page 133 Thursday, August 23, 2007 5:43 PM 134 Chapter 2  Effectively Working with Personal Computer Components 13. Display devices can be connected to a PC using DB-15 connectors or ________. A. HDT B. DVI C. VBA D. VBP 14. What utility can be used with Windows XP to format drives? A. Disk Design B. Disk Plan C. Disk Management D. Disk Prep 15. Which ATA standard supports UltraDMA/133? A. ATA-7 B. ATA-8 C. ATA-9 D. ATA-10 16. What type of female DB-style connector does SCSI-2 use? (Choose all that apply.) A. 25-pin B. 50-pin C. 68-pin D. 72-pin 17. Internally, what type of wire ribbon cable does SCSI use? A. 25-pin B. 50-pin C. 68-pin D. 72-pin 18. When changing display devices or upgrading to a newer one, what is one of the most crucial components to have? A. Manufacturer’s resolution recommendations B. Antistatic mat C. Ribbon cable D. Correct driver 4830c02new.fm Page 134 Thursday, August 23, 2007 5:43 PM Review Questions 135 19. Every computer has a diagnostic program built into its BIOS called the ________. A. CMOS B. BIOS C. POST D. DNS 20. What two devices are commonly used to cool components within a PC? (Choose two.) A. Fans B. Compressed air C. Freon D. Heat sinks 4830c02new.fm Page 135 Thursday, August 23, 2007 5:43 PM [...]... 2007 5: 43 PM Answers to Review Questions 137 18 D The correct driver is needed in order to assure the new display device works as it should 19 C Every computer has a diagnostic program built into its BIOS called the power-on self-test (POST) 20 A, D Heat sinks and fans are commonly used to cool components within a PC 4 830 c02new.fm Page 138 Thursday, August 23, 2007 5: 43 PM 4 830 c 03. fm Page 139 Thursday,... 7680 × 4800 pixels (37 million total) at a16:10 aspect ratio 4 830 c 03. fm Page 152 Thursday, August 23, 2007 5:47 PM 152 Chapter 3 Understanding Laptops and Portable Devices Table 3. 1 highlights the some LCD video standards, their standard resolutions, and their aspect ratio: TABLE 3. 1 LCD Video Standards Name Resolution Ratio Extended Graphics Array (XGA) 800 × 600 1024 × 768 4 :3 4 :3 Super eXtended Graphics... with a special cable to a proprietary connector Figure 3. 4 shows an example of one of these connectors, and Figure 3. 5 shows an example of a laptop floppy drive Notice how thin the floppy drive is and how compact the electronics are FIGURE 3. 4 A proprietary floppy connector 4 830 c 03. fm Page 148 Thursday, August 23, 2007 5:47 PM 148 Chapter 3 FIGURE 3. 5 Understanding Laptops and Portable Devices A laptop... platform 4 830 c 03. fm Page 157 Thursday, August 23, 2007 5:47 PM Understanding Laptop Architecture 157 Finally, PCMCIA version 3 (PCMCIA 5.0) increased the bus width to 32 -bit and the bus speed from 8MHz to a maximum of 33 MHz In addition, the new CardBus adapters used PCI-like access methods, and the throughput speeds increased dramatically (at the time this text was written, speeds up to 132 Mbps were... outside of the case Mini PCI is functionally identical to the PCI version 2.2, meaning it’s a 32 -bit, 33 MHz bus with a 3. 3V-powered connection It also supports bus mastering and DMA There are three different Mini PCI form factors: Type I, Type II, and Type III The size and connector types are listed in Table 3. 2 TABLE 3. 2 Mini PCI Form Factors Type Connector Size IA 100-pin, stacking 7.5 × 70 × 45 millimeters... 13 B Digital Visual Interface (DVI) connectors can be used to connect display devices to PCs 14 C The Disk Management utility can be used in Windows XP to format drives 15 A ATA-7 supports UltraDMA/ 133 16 A, B, C SCSI-2 uses a 25-, 50-, or 68-pin female DB-style connector 17 B SCSI internal cabling uses a 50-wire ribbon cable with several keyed connectors 4 830 c02new.fm Page 137 Thursday, August 23, ... square of plastic (usually a very dark maroon) and can typically be found on the front of a PC or on the side of a laptop or portable Figure 3. 11 shows an example of an infrared port 4 830 c 03. fm Page 160 Thursday, August 23, 2007 5:47 PM 160 Chapter 3 FIGURE 3. 11 Understanding Laptops and Portable Devices An infrared port Infrared ports send and receive data at a very slow rate (maximum speed on most... preventative maintenance on laptop computers 4 830 c 03. fm Page 142 Thursday, August 23, 2007 5:47 PM 142 Chapter 3 Understanding Laptops and Portable Devices Understanding Laptop Architecture Laptops are similar to desktop computers in architecture in that they contain many parts that perform similar functions However, the parts that make up a laptop are completely different from those in desktop computers... producing One of the original problems with LCD displays, and a continuing problem with cheaper versions, is that they have low ratios A display with a low ratio 4 830 c 03. fm Page 1 53 Thursday, August 23, 2007 5:47 PM Understanding Laptop Architecture 1 53 won’t show a “true black” very well, and the other colors will look washed out when you have a light source nearby Try to use the device in full sunshine,... laptop is considerable This is not to say that a laptop can’t outperform a desktop, it’s just that the “bang for the buck” factor is higher in a desktop 4 830 c 03. fm Page 1 43 Thursday, August 23, 2007 5:47 PM Understanding Laptop Architecture 1 43 Expandability Because desktop computers were designed to be modular, their capabilities can be upgraded quite easily It is next to impossible to upgrade the . PC. 4 830 c02new.fm Page 137 Thursday, August 23, 2007 5: 43 PM 4 830 c02new.fm Page 138 Thursday, August 23, 2007 5: 43 PM Chapter 3 Understanding Laptops and Portable Devices THE FOLLOWING COMPTIA. manufacturer’s trademark D. Parity 4 830 c02new.fm Page 133 Thursday, August 23, 2007 5: 43 PM 134 Chapter 2  Effectively Working with Personal Computer Components 13. Display devices can be connected. 80-wire cable C. Operating system support D. All of the above 4 830 c02new.fm Page 132 Thursday, August 23, 2007 5: 43 PM Review Questions 133 7. On the primary IDE channel, if a single hard disk is attached,