Maintaining and Troubleshooting Peripheral Components

Troubleshoot Display Devices
In the last lesson, you installed and configured computer hardware components. The next step is to troubleshoot hardware, and a good place to start is with the monitor. In this topic, you will start by troubleshooting display devices.
Display issues can be very disconcerting for users; after all, if they cannot see output on the monitor, it is as if they are flying blind. Most display device problems have simple causes that you can help users resolve easily. However, if the user cannot determine how to solve a par- ticular issue, or if the symptoms indicate more extensive problems, you will need to step in to correct the situation.
Common Display Device Issues
There are many problems you might encounter when troubleshooting display devices.

Symptom
Monitor is dark or power indicator light is not lit.
No image.

Possible Problems and Solutions
This indicates general power problems, such as the power is not turned on, the power cable is disconnected, or the power is on but the monitor is plugged into a power strip, surge protector, or UPS that is not turned on. To correct the problem, turn on the power or power strip and reconnect the cables and cords. If a circuit breaker has tripped, reset it. Press or jiggle the power button on the monitor itself. A fuse in the monitor may have blown. Do not open the monitorto change a fuse; send the monitor out for repair, or replace it.
If there is no power light, check for and correct power problems.
The data cable to the VGA port on the PC may be disconnected. Except on very old monitors, you will see an On Screen Display (OSD) message in this case, indicating a signal problem. Connect or re-seat the cables and connectors. If the cable is disconnected, and you do not see an OSD mes- sage, the monitor is bad.
Brightness or contrast may be adjusted improperly. Adjust the settings using the monitor controls. (The OSD message is not affeted by brightness or contrast.)
The monitor may be in power saving mode. The power light will typically change from green to solid or blinking amber. Press a key or move the mouse to wake up the monitor.

Symptom
Flickering or distortion.

Possible Problems and Solutions
The monitor cable may not be securely connected to the video port or there are bent or broken pins. Straighten bent pins and re-seat the cable. Use caution; a severely bent pin may break, in which case you will need to replace the monitor. A few cables are removable, in which case you can replace the cable.
Incorrect display adapter and monitor device drivers may be in use. Through Device Manager, verify that the correct display adapter and monitor device drivers are in use.
Refresh rate may be too low or too high. For viewer comfort, set the refresh rate as high as supported by the monitor and adapter card, but no higher. If the rate is too high, it can damage the monitor, and the monitor may go into power-saver mode.
If the monitor is interlaced, replace it with a non-interlaced monitor. (Interlaced monitors refresh the pixel display with multiple passes of the electron beam; non-interlaced monitors refresh the entire display in a single pass. Generally, interlaced monitors have less flicker, but only if they support as high a refresh rate as a non-interlaced monitor.)
There may be magnetic buildup. Degauss (demagnetize) the monitor by turning it off and on or by pressing the Degauss button.
The monitor may be too close to other electronic or magnetic equipment. Relocate the monitor.
The color depth setting may be incorrect. Adjust the color depth.
Power management is enabled. You can adjust this either in CMOS set- tings or in the operating system Display Properties:

• ●  In CMOS, if the ACPI power settings are enabled, you can use the Dis- play Properties Screen Saver and Monitor Power settings to control when the power is lowered or turned off to the monitor.
  
• ●  In Display Properties, on the Screen Saver page, adjust the Wait Time to meet the user’s needs. Click the Power button to access the Power Schemes and settings for the Power Options Properties dialog box and set those as appropriate to the user’s needs as well.
  If the screen goes blank, flickers, or acts erratic when a specific applica- tion is active, the application may require different color quality (also known as color depth) or screen resolution. Adjust settings on the Settings page of the Display Properties dialog box.
  This unusual state could be due to multiple bent or broken pins.
  Crackling can be caused by dirt: clean the monitor. If there is dust inside the monitor, to avoid electrical hazards, do not open the monitor! If nec- essary, send it to a monitor repair facility for more in-depth cleaning. Crackling can be caused by failing electrical components; you will smell burning wire. Shut off and disconnect the monitor to eliminate fire and health hazards, and send the monitor for repair or replacement.
  If it whines, try moving the monitor away from sources of EMI, or replac- ing it with a quieter monitor. This can also be caused by damaged components, in which case you will need to send the monitor for repair or replacement if it is under warranty.
  

Symptom
Physical damage.

Possible Problems and Solutions

If the display device has been dropped or tipped, it may have sustained internal or external physical damage that cannot be corrected by any other troubleshooting technique. It is generally more economical and certainly safer to replace the device rather than attempting repair. However, if you must attempt repair on internal monitor components, avoid electrical haz- ards and do not open the monitor. Send the monitor to an authorized repair facility.

Maintain and Troubleshoot Input Devices
In the previous topic, you corrected problems with display devices. You might also need to troubleshoot mice, keyboards, and other input devices. In this topic, you will maintain and troubleshoot input devices.
Input device problems can bring users to a standstill. If they cannot interact with their com- puter systems, they can get very little work done. They will turn to you as a computer support professional to resolve this issues for them very quickly. Fortunately, most input device troubleshooting is straightforward and relies most on common sense. Plus, you can avoid many input device problems if you can help computer users to care for these devices properly.
Common Input Device Issues
Common input devices such as keyboards and mice are inexpensive to replace if they are dam- aged beyond repair. Most routine troubleshooting involves cleaning the device or ensuring that it is properly connected. Specialty input devices such as a touch-screen monitor may have device-specific issues; if common troubleshooting techniques are not effective, check the device documentation for the appropriate next steps.

Symptom
New keyboard won’t plug into the same port as the old keyboard.

Possible Problems
Very old keyboards used a large 5-pin DIN connector. Today’s keyboards use either the smaller 6-pin mini-DIN connector, also called a PS/2 style connector, or a USB connector.

Solutions
In some cases, because the keyboards are the same except for the connector, you can buy an adapter to allow you to plug the new keyboard into the old port on the system board. The simplest approach is to make sure your system and peripherals have compat- ible ports and connectors.

Specific Pointing Device Problems

There are some common problems that you will encounter that are common to mice, trackballs, and other pointing devices.

Symptom
Mouse pointer jumps around on the screen.

Possible Problems
Mouse ball or rollers are dirty.
Mouse has reached the end of its useful life.
Mouse is not being rolled over a flat surface.
Mouse is being rolled over a dirty mouse pad.
Mouse settings are incorrect.

Solutions
Visually inspect the mouse, the mouse pad, and the area around the mouse.
Clean the mouse; replace the mouse pad. An optical mouse might need a different mouse pad because white, light-colored, or patterned pads might interfere with the optical sensor.
Use the Device Manager and Help And Support Center utilities to check the status of the pointing device.
With an older mouse, regular maintenance might reduce this problem, but not elimi- nate it.

From Control Panel, open Printers And Other Hardware. Click Mouse. Check the pointer speed, click speed, and other settings that might affect performance.

Input Device Maintenance Techniques
You can avoid many input device problems if you maintain common devices properly.

• ●  Occasionally disconnect keyboards and mice and gently wipe them clean.
  
• ●  Clean loose debris from inside a trackball or mouse.
  
• ●  Gently shake an upside-down keyboard to remove debris.
  
• ●  Provide a clean, flat mouse pad or other mousing surface.
  
• ●  To avoid spills that can damage input devices, keep food and liquids away from computer
  systems.
  
• ●  Replace cordless device batteries regularly.
  Cleaning Mice and Trackballs
  To clean a standard mouse or trackball, remove the ball, clean the rollers with rubbing alcohol and a lint-free swab, wipe the mouse ball down with the alcohol, and reassemble the mouse once it is dry.
  To clean a wireless mouse, use a soft brush or compressed air to clean dust or debris around the optical sensor. Keep the compressed air at a distance to avoid freezing the sensor plastics. 
  

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Install and Configure System Boards

Install and Configure System Boards
In the last topic, you installed and configured CPUs. The final system component that you might need to install is the system board. In this topic, you will install and configure a system board.
The most important system component in a computer is the system board. Although you can argue a case for almost any system component as being most important, without the system board, the computer simply cannot run. It’s possible that you will be asked to either build a computer from scratch or to replace the system board in a failed computer. In either case, whether you are building a computer from scratch or repairing a failed computer, you must be prepared to install and configure a new system board. 

System Board Selection Tips
You choose a system board based on whether it supports the components you need for the computer.

System Component
RAM CPU Ports
Expansion slots Drive interfaces
Form factor Clock speed

Questions To Ask
Does the system board support enough RAM to meet the user’s needs?
What type of processor can you install? Can you install more than one CPU?
Does the system board have the necessary ports to meet the user’s needs? Specifically, does it have the parallel, serial, USB, and possibly even FireWire ports needed?
How many expansion slots will the user need? What types of slots does it include?
Does the system board include drive interfaces? If not, does it have enough available expansion slots to accommodate the user’s hard disk requirements?
Will the system board fit inside the case of the computer?
Does the system board operate at a high enough frequency to support the processor you want to use?

System Board Installation Considerations
When you are replacing a system board, specific requirements need to be considered and can also depend on the manufacturer’s requirements for the system. You need to make sure you get one that fits your case. This is because the holes in the system board need to line up with the connections in the case. The system board is secured to the case using these connections. Also, when replacing the cover on the case, you must make sure the cover is properly aligned. If the cover isn’t properly aligned, it might affect the cooling system and the operation of the internal drives.
Computer Cases
The computer case is the enclosure that holds all of the components of your computer. Com- puter cases come in several formats. Some are designed to hold many internal components and have a lot of room to work around those components. These cases are usually tower cases and take up a good deal of room. Other cases are designed to use a minimum amount of space. The trade-off is that the interior of the case is often cramped, with little room for adding addi- tional components. Because the tower proved to be popular, there are now several versions of the tower model. 

System Board Configuration and Optimization
Requirements
When you replace or install a new system board, you must ensure that it is properly configured to match the processor that it will host. In essence, you must configure the system board so that the internal and external frequencies of the processor are compatible. You accomplish this by specifying a frequency multiple. Most system boards operate at a specific speed, but some enable you to select the speed via DIP switches, jumpers, or the BIOS setup software.
DIP Switches and Jumpers
To configure older system boards, you used either DIP switches or jumpers. You might have used these switches to specify the multiplier and the CPU bus frequency. Newer system boards enable you to use software to configure these values (through the BIOS Setup program).

System Board Power Connectors
The power supply connection to the system board is a keyed or unkeyed connection that enables the power supply to supply power to the internal components of the system. Keyed connectors are designed so that the plug and socket have notches that must line up in order for the plug to fit into the socket. The connection also might use a single connector or two connectors. If there are two connectors, they are labeled P8 and P9. Be sure not to switch them when you plug them in or you could damage the system board. Most systems have a single, keyed connector that is inserted only one way, which avoids damage to the system board.

Power supplies have connections to other internal components as well. There are Berg and Molex connections and a connection to the power switch for the system.

Specific Connectors

There are specific connectors, depending on the motherboard requirements, usually tied to the CPU type. There’s the 20-pin (ATX), a 24-pin ATX connector, and the 20+4 combo (which you can separate, or not, depending on the motherboard). This includes a 20-pin for the main power, plus a 4-pin connector for additional CPU power. This 4-pin is sometimes known as the Intel Pentium 4 connector. There’s also an 8-pin CPU connector that requires an ATX 2.02, or EPS12V, PSU.

How to Install and Configure System Boards 
Procedure Reference: Install or Upgrade a System Board

To install or upgrade the system board:

you are upgrading the computer’s system board, remove the original system board.

1. Shut down the system and unplug the power cord.
   
2. Disconnect all external devices.
   
3. Remove the system cover.
   
4. Remove all expansion cards and store them in anti-static bags. (Before removing components from the system board, you might want to take a picture of the assembled board so that you can use it as a reference when you reconnect the com- ponents later.)
   
5. Disconnect cables from the system board, marking each cable as to what it connects to and where it goes.
   
6. Unscrew the system board from the case.
   
7. Lift the system board out of the case. On some systems, after lifting the system board over the pin(s), you will need to slide it out of the case.
   

2. Install the new or replacement system board.

1. Place the new system board into the case and align the mounting holes.
   
2. Secure the system board to the case.
   
3. Install RAM and processor(s) on the new system board. Some sources recommend installing these components prior to installing the system board. If you do this, be careful not to bend the board or mash any connectors on the bottom side of the sys- tem board as you insert the components.
   
4. Reinstall cards and cables removed from the old system board.
   
5. Replace the system cover. 
   

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Install and Configure CPUs

Install and Configure CPUs
In the previous topics, you installed RAM. Another way to increase the performance of a per- sonal computer is to install a second processor or upgrade the existing processor. In this topic, you will install and configure processors.
Have you ever tried to get a new piece of software or a game to run only to find out that your processor is too slow? If this happens to the users you support, they will want you to fix the problem, which might mean upgrading the CPU. This might seem like a drastic measure, and it can be expensive, but in some cases, it is less expensive to upgrade the CPU than it is to purchase a new system if everything else in a user’s computer provides acceptable performance.
CPU Chip Types
CPU chips are developed by several different manufacturers. 

CPU Manufacturer
Intel
AMD Cyrix

Sample CPUs
Intel CPUs include 8086, 8088, 80286, 80386SX, 80386DX, 80486SX, 80486DX, Pentium, Pentium MMX, Pentium Pro, Pentium II, Pentium III, Pentium 4, Celeron, Xeon, Duo core, and Itanium, to name a few.
AMD CPUs include the K5, K6, Duron, Athlon, Opteron, and Althon 64 processors.
While no longer in business, Cyrix manufactured the MediaGX and M II processor, among others.

CPU Chip Types 

Instruction Sets
An instruction set is the collection of commands that is used by a CPU to perform calculations and other computing operations. Every manufacturer has its own instruction set.
There are three main categories of instruction sets used.

Instruction Sets

Instruction Set
Complex Instruction Set Computer (CISC)

Description
A design strategy for computer architectures that depends on hardware to perform complicated instructions.
Does not require instructions to be of a fixed length.
Allows for more complicated functions to be executed in one instruction. Most Intel processors fall into this category. 

Instruction Set
Reduced Instruction Set Computer (RISC)
Explicitly Parallel Instruc- tion Computing (EPIC)

Description
A design strategy for computer architecture that depends on a combina- tion of hardware and software to perform complicated instructions. Requires instructions to be of a fixed length.
RISC instructions are simpler and fewer than CISC, but more instructions are required to carry out a single function.
IBM, Motorola, and Sun manufacture RISC chips.
IBM RS/6000, Sun Microsystems, and some Macintosh computers use RISC.
A design strategy for computer architecture that is meant to simplify and streamline CPU operation by taking advantage of advancements in com- piler technology and by combining the best of the CISC and RISC design strategies.
EPIC-based processors are 64-bit chips.
Intel IA-64 architecture, including Intel Itanium processors, is based on EPIC.

Cache Memory 
Definition:
Cache memory, or CPU cache, is a type of memory that services the CPU. It is faster than main memory and allows the CPU to execute instructions and read and write data at a higher speed. Instructions and data are transferred from main memory to the cache in blocks to enhance performance. Cache memory is typically static RAM (SRAM) and is identified by level. Level 1 (L1) cache is built into the CPU chip. Level 2 cache (L2) feeds the L1 cache. L2 can be built into the CPU chip, reside on a separate chip, or be a separate bank of chips on the system board. If L2 is built into the CPU, then level 3 cache (L3) can be present on the system board.

Cache Write Policy
The cache’s write policy determines how it handles writes to memory locations that are cur- rently being held in cache. There are two policy types.

Cache Policy Type
Write-back cache
Write-through cache

Description
When the system writes to a memory location that is held in cache, it writes only the new information to the appropriate cache line. When the cache line is needed for another memory address, the changed data is written back into system memory. This type of cache provides better performance than a write-through cache, because it saves write cycles to memory.
When the system writes to a memory location that is held in cache, it writes the new information simultaneously to the appropriate cache line and to the memory location. This type of caching pro- vides lower performance than write-back, but it is easier to implement and has the advantage of internal consistency, because the cache and memory are identical at all times. 

CPU Operational Characteristics
There are many different characteristics and technologies that can affect a CPU’s performance.

CPU Operational Characteristics

CPU Characteristic or Technology
Bus width Clock speed
Overclocking
CPU speed
Throttling
Hyperthreading
Dual core
Cache
Voltage Regulator Module Multimedia Extensions

Description
A CPU’s internal bus width is either 32 or 64 bits.
The number of processing cycles that a microprocessor can perform in a given second. Some CPUs require several cycles to assemble and perform a single instruction, whereas others require fewer cycles. The clock speed is a technical rating; actual performance speeds can vary from the published clock speed rating.
Configuring your system board to run at a speed greater than your CPU is rated to handle. Doing so can cause the CPU to overheat, produce random results, or be damaged or destroyed.
CPU speed is an umbrella term for the overall rate at which instructions are processed. There are two factors that affect the CPU speed. One is the core clock speed, which is the internal speed at which instructions are processed within the CPU. The other is the bus clock speed, which is the speed at which instructions are transferred to the system board.
To adjust CPU speed. A CPU throttle is typically used to slow down the machine during idle times to conserve battery or to keep the system running at a lower performance level when hardware problems have been encountered.
A feature of certain Pentium 4 chips that makes one physical CPU appear as two logical CPUs. It uses additional registers to overlap two instruction streams to increase the CPU’s performance by about 30%.
A single chip that contains two distinct CPUs that process simultaneously. The first dual core chips for x86-based PCs and servers were introduced in 2005.
Dedicated high-speed memory for storing recently used instructions and data.
VRM is a replaceable module used to regulate the voltage fed to the CPU.
MMX is a set of additional instructions, called microcode, to support sound, video, and graphics multimedia functions.

Processor Specifications
The following table summarizes some of the specifications for popular processors.

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Install and Configure Memory

Install and Configure Memory
In the last topic, you installed a power supply. Providing sufficient electrical power is one way to ensure that system components run at an acceptable performance level, but it is not the only solution you should consider. In this topic, you will install and configure memory.
Just as some people say you can never be too rich or too thin, you can never have too much memory. Adding memory is one of the simplest and most cost effective ways to increase a computer’s performance, whether it’s on a brand-new system loaded with high-performance applications or an older system that performs a few basic tasks. One way or the other, upgrad- ing the memory is a frequent task for any computer service professional.
Memory Modules Definition:
A memory module is a printed circuit board that holds a group of memory chips that act as a single memory chip. Memory modules reside in slots on the system board, and they are removable and replaceable. Memory modules are defined by the number of chips they contain.

Memory Form Factors and Slot Types
Memory modules come in several form factors, and each module will connect to the system board through a memory slot of a compatible type.

Memory Form Factor
Single In-line Memory Module (SIMM)
Dual In-line Memory Mod- ule (DIMM)
Rambus Inline Memory Module (RIMM)
Memory Types

Description
Generally found in older systems, SIMMs have a 32-bit data path. Because most processors now have a 64-bit bus width, they required that SIMMs be installed in matched pairs so that the processor could access the two SIMMs simultaneously. SIMMs generally have 8 memory chips per module. Only SIMMs can be installed into SIMM slots on the system board.
DIMMs are found in many systems, and they have a 64-bit data path. The development of the DIMM solved the issue of having to install SIMMs in matched pairs. DIMMs also have separate electrical contacts on each side of the module, while the contacts on SIMMs on both sides are redundant. DIMMs generally have 16 or 32 chips per module. Only DIMMs can be installed into DIMM slots on the system board.
RIMMs have a metal cover that acts as a heat sink. Although they have the same number of pins, RIMMs have different pin settings and are not interchangeable with DIMMs and SDRAM. RIMMs can be installed only in RIMM slots on a system board.

Random Access Memory (RAM) is the main memory. The computer can both read the data stored in RAM and write different data into the same RAM. Any byte of data can be accessed without disturbing other data, so the computer has random access to the data in RAM. RAM is volatile and requires a constant source of electricity to keep track of the data it is storing. If the electricity is cut off, RAM forgets everything.
There are several types of RAM.

Type of RAM
SRAM
DRAM
DRDRAM SDRAM

Description
Static RAM is used for cache memory, which is high-speed memory that is directly accessible by the CPU. It does not need to be refreshed to retain information. It does not use assigned memory addresses. It is faster than Dynamic RAM, but it is also more expensive.
Dynamic RAM is used on single and dual in-line memory modules (SIMMs and DIMMs). It is the most common type of RAM. It needs to be refreshed every few milliseconds. Uses assigned memory addresses. Can be implemented using Synchronous DRAM, Direct Rambus DRAM, or Double Data Rate SDRAM.
Direct Rambus DRAM is implemented on a RIMM memory module.
Synchronous DRAM runs at high clock speeds and is synchronized with the CPU bus. SDRAM was originally packaged on a 168-pin DIMM.

Type of RAM
DDR SDRAM
DDR2 SDRAM
Sequential Access Memory (SAM)
RAM Speed

Description
Double Data Rate SDRAM transfers data twice per clock cycle. It is a replacement for SDRAM. DDR uses additional power and ground lines and is packaged on a 184-pin DIMM module.
DDR2 chips increase data rates over those of DDR chips. DDR2 mod- ules require 240-pin DIMM slots. Although DDR2 chips are the same length as DDR, they will not fit into DDR slots.
SAM is volatile memory that holds data in a sequential order. When accessing data, each storage cell is checked until the desired information is found. Often used for memory buffers where data is stored in the order it will be used.

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RAM speed is the time needed to read and recharge a memory cell. It’s measured in nanosec- onds (ns). A nanosecond is one-billionth of a second. The smaller the number, the faster the RAM. For example, 10 ns RAM is faster than 60 ns RAM.
RAM comes in ever-increasing speeds. The RAM on sale at the local computer store might work just fine in your system, or it might be older, slower RAM they are trying to move out of stock.
Older EDO RAM was often 60- to 70-ns speed RAM. Modern RAM that you are likely to find runs at clock speeds of 100 MHz and 133 MHz. The 100 MHz RAM has a RAM speed of 10 ns. The 133 MHz RAM has a RAM speed of 6 ns.

You need to check what RAM speed is currently installed. All of the RAM in the system runs at the lowest common speed. It is backward-compatible, so it can run at the lower speed if it finds slower RAM. Some systems will not run with mixed RAM speeds, but these are not common. Either way, the RAM will not run any faster than the system board’s bus speed.
DRAM Banks

You can combine multiple rows of DRAM into a cluster called a bank. Each row of DRAM can then be accessed simultaneously. When creating banks, the goal is to match the width of the DRAM to the width of the CPU’s external data bus, which will generally be 8-bit, 16-bit, 32-bit, or 64-bit. Expressed another way, the number of SIMMs or DIMMs needed to create a bank is the width of the CPU’s data bus divided by the width of the SIMM or DIMM. So, for a CPU with a 32-bit data bus, you need four SIMMs to create a bank.

Types of ROM
ROM is memory that is non-volatile. The original ROM chips could not be altered after the program code was placed on the ROM chip. As time went on, though, users needed the ability to update the information stored on ROM chips. Over the years, various chips have been cre- ated that perform the function of ROM, but can be updated one way or another. These are referred to as programmable ROM (PROM). Types of ROM include:

• ●  PROM: A blank ROM chip that is burned with a special ROM burner. This chip can be changed only once. After the instructions are burned in, it cannot be updated or changed.
  
• ●  EPROM (erasable PROM): Like PROM, except that the data can be erased through a quartz crystal on top of the chip. After removing the chip from the system, a UV light is used to change the binary data back to its original state, all 1s.
  
• ●  EEPROM (electronically erasable PROM): A chip that can be reprogrammed using soft- ware from the BIOS or chip manufacturer using a process called flashing. Also known as Flash ROM. The chip does not need to be removed in order to be reprogrammed.
  Memory Selection Tips
  There are several factors you should consider when purchasing RAM for a computer.
  

RAM Characteristics
Size
Speed
System Board Configuration

Questions to Ask
What is the maximum RAM size supported by the computer’s system board?
What is the current speed of the RAM in the com- puter? What is the bus speed of the computer?
Do you need to install RAM in pairs of memory modules? What is the size of the connector for RAM chips?

How to Install and Configure Memory Procedure Reference: Add RAM to a Computer
To add RAM to a computer:

1. Review the computer’s current configuration to make sure that the computer’s memory slots aren’t already full.
   
2. Determine how much RAM is currently installed so that you can determine afterwards if the new RAM you installed is recognized. You can check the CMOS settings or use the System Properties dialog box in Windows XP to verify the amount of RAM.
   To check the RAM through System Properties:
   
   1. From the Start menu, choose My Computer.
      
   2. In the System Tasks box on the left side of the window, click View System Information.
      
3. Shut down your computer and disconnect the power cord. Press and hold the power but- ton down for 10–30 seconds to release any stored energy in the system.
   
4. Discharge any static electricity from yourself or your clothes. Although this is always important to do, it is especially important to do when working with memory cards. These components are more delicate and more easily damaged by static charges than other sys- tem components.
   
5. Locate an empty memory expansion socket on the system board, or, if there are no empty slots, remove a smaller memory module to make room for one containing more memory.
   To remove an existing memory module:
   
   1. Press down on the ejection tabs.
      
   2. Firmly grasp the memory module and pull it out of the slot.
      
6. Align the notches in the connector edge of the memory module with the notches in the memory expansion socket, and then firmly press the memory module down into the socket.
   
7. If the ejection tabs did not lock into the notches on the ends of the memory module, push them up until they lock.
   
8. Restart the computer.
   
9. Follow any on-screen prompts or perform any steps described in your computer’s docu- mentation for getting the computer to recognize additional memory. This is not required on all computers. 
   

 

 

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Install and Configure Power Supplies

Install and Configure Power Supplies
In the previous topic, you installed and configured storage devices. The next system compo- nents you’ll focus on are power supplies. In this topic, you will install and configure a power supply in a computer.
Underpowered systems, especially older systems with relatively small power supplies, can experience lockups, random reboots, and other quirky behavior. If you are upgrading compo- nents, you might exceed the capacity of the current power supply. Replacing it with an adequate power supply can prevent system power problems and keep the number of support calls down.
Power Supply Form Factors
Like system boards and other components, there are several form factors available for power supplies.
Power Supply Form
Factor Description
AT Used in AT form factor cases and with AT or Baby AT system boards. Dimensions are 213 x 150 x 150 mm. Found in older desktops and
towers. AT power supplies have physical on-off switches.
ATX Used in ATX and NLX cases and with ATX and NLX system boards. Dimensions are 150 x 140 x 86 mm. Found in desktops and towers.
ATX power supplies do not have physical on-off switches. The system board actually controls the power state of the ATX power supply.
Proprietary Some computer manufacturers use system board form factors that do not conform to standards such as ATX, NLX, and BTX. It’s likely that these proprietary system boards will require nonstandard power supply form factors as well, although you might be able to use an ATX power
supply.
Power Supply Wattage
Power supply specifications are given in watts. A watt is volts times amps (voltage x amperes). Older systems typically had power supplies under 200 watts and often even under 100 watts. Newer power supplies typically have wattages ranging from 200 to 500 watts. Because of their increased power demands, computers designed for games can have power supplies with watt- ages from 500 watts up to 1 kilowatt.

Calculating Power Needs
In order to calculate whether your power supply meets your power needs, you will need to add up the maximum power you might use at one time. A range of maximum power consumption for various components has been established. Most components use much less than the maximum. You can check the documentation for the component to determine how much power it actually will use.
AC Power for Peripherals
Although internal system components rely on the power supply, other devices such as printers and external modems require their own direct supply of AC power. In such a case, you must plug the device directly into a source of AC power such as a wall socket or power strip.
CPU Voltages
Even some of the most powerful current CPUs, such as the Intel Core2 Extreme and the AMD Opteron Dual Core, only use 1.1-1.3 V. Necessary voltage for CPU and RAM is usually detected by the motherboard (BIOS) and configured appropriately, but sometimes you have to manually configure it, by accessing the BIOS and entering the appropriate values. The Power supply will supply 3.3 V for the CPU, RAM, and other devices, but the motherboard regulates how much they actually get.
Power Supply Safety Recommendations
There are a number of safety precautions you should observe when working with power supplies.

Safety Precaution
Check for certification
Replace instead of repairing the power supply
Keep the computer case on

Explanation
Be sure to purchase power supplies that are certified by the Underwriters Laboratories, Inc. (UL). UL standard #1950, the “Standard for Safety of Information Technology Equipment, Including Electrical Business Equip- ment, Third Edition,” regulates computer power supplies (along with other components). When it comes to electricity, you don’t want to take a chance with a non-certified power supply. The risk of electrocution or fire from a malfunctioning power supply is simply not worth saving a few dollars by purchasing a low quality power supply.
You run the risk of electrocution if you open a power supply to attempt to repair it. Even when you unplug a computer, the power supply can retain dangerous voltage that you must discharge before servicing it. Because power supplies are relatively inexpensive, it’s easier (and safer) to simply replace a failed power supply rather than attempting to repair it.
Make sure that you run computers with their cases on. The fans inside power supplies are designed to draw air through the computer. When you remove the cover, these fans simply cool the power supplies and not the computer’s components. Leaving the case open puts the computer at risk of overheating.

Safety Precaution
Protect the power supply

Explanation
Use a power protection system such as an uninterruptible power supply (UPS) or surge suppressor to protect each computer’s power supply (and thus the computer) from power failures, brownouts, surges, and spikes. You should also make sure that the computer’s power cord is plugged into a properly grounded electrical outlet. (Three-pronged outlets include grounding; never use an adapter to plug a computer’s power cord into a two-pronged electrical outlet.) You can buy a socket tester (available at hardware stores) to test your outlets if you suspect that they aren’t prop- erly grounded.

Power Supply Selection Tips
There are several criteria you should use when selecting a power supply for a computer.

Criteria
Power supply rating
Form factor Cooling
Power Supply Fan

Explanation
Make sure that you don’t overload the power supply. Add up the total system requirements for power and then select a power supply that can meet the computer’s demands.
Verify that the power supply will fit in your computer’s case and conform to your system board’s form factor.
Ensure that the power supply you select can adequately cool the components within the computer’s case.

Some power supplies enable you to see the revolutions per minute (RPMs) of the power sup- ply fan. You can then adjust the fan speed to run at only the speed needed to cool your system. This can reduce power consumption and save wear and tear on the fan.

How to Install and Configure Power Supplies
Procedure Reference: Calculate Power Needs
To calculate the amount of power needed for a computer system:

1. Determine the number of watts used by each component in the computer. Make sure you include the following components:
   
   • ●  System board
     
   • ●  CPU
     
   • ●  RAM
     
   • ●  Hard drives
     
   • ●  CD drives
     
   • ●  DVD drives
     
   • ●  Floppy drives
     
   • ●  Expansion cards
     
2. Add up all of the power needed by the system components.
   
3. Look at the label on the power supply to see what the maximum wattage output is.
   
4. Compare your computation with the power supply output. If you have not exceeded the power available, you do not need to upgrade. If you have, you will need to obtain a suit- able power supply and install it.
   
   

 

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Installing and Configuring System Components

TOPIC A
Install and Configure Storage Devices
In this lesson, you will install and configure system components. Storage devices such as hard disks are one of the most common system components you will install. In this topic, you will install and configure storage devices.
Users rely on local storage devices to keep their applications and data current and available. As an A+ technician, your responsibilities are likely to include installing and configuring dif- ferent types of storage devices to provide your users with the data-storage capabilities that they need to perform their jobs.
Hard Disk Drive Types
There are many types of hard disks as well as the hard disk controllers that enable the disk to connect to the system board.

Extending IDE Drive Capabilities
The original IDE specification limits hard drive size to 504 MB. Three ways were developed to overcome this limitation.

• ●  You can extend the drive size limit to 8.4 GB through the use of Logical Block Address- ing (LBA) or Extended CHS (ECHS). With LBA or ECHS, hard drives can be up to 8.4 GB in size. LBA and ECHS are methods of sector translation (translating a hard drive’s logical geometry into physical geometry) that essentially give the BIOS incorrect informa- tion about the geometry of the drive so that larger hard-drive capacities can be supported, while staying within BIOS limitations. The cylinder value after translation never exceeds 1,024. LBA was developed by Western Digital. ECHS was developed by Seagate. They differ only in the sector translation results they produce. If you want to move a hard drive from one computer to another, then the other computer must support the same sector translation method as the computer from which you are removing the hard drive. Other- wise, you will lose the data on the disk if you move the drive. This is a problem mostly if one computer is significantly older than another. But you do want to check and always back up your data before moving a drive. Today’s hard disks and BIOSs all support LBA and ECHS to accommodate the need for large disk capacity.
  
• ●  To address the need for even larger hard drive capacities, Phoenix Technologies developed Interrupt 13h (INT13h) extensions. Developed in 1994, INT13h extensions are a newer set of BIOS commands that enable support for hard drives larger than 8.4 GB. This support
  is made possible by using 64 bits for addressing, instead of 24 bits, and by using 1,024 cylinders. This expands hard drive support for drives up to 137 GB. INT 13h extensions are supported by modern hard drives and Windows 95 and newer operating systems, but must also be supported by the system BIOS or the hard-disk controller.
  
• ●  If you need to support hard disks greater than 137 GB, you can use large LBA translation mode. It uses 48 bits for addressing instead of 24 bits.
  PIO Modes
  The ATA and ATA-2 standards use the Programmed Input/Output Mode (PIO Mode) to indicate the speed of data transfer between two devices that use the computer’s processor as a part of the datapath. The PIO Mode is set in the BIOS. It is originally set when you install an IDE or EIDE drive. The following table lists the transfer rate for several ATA and ATA-2 standards.
  

Standard/PIO Mode
ATA/0 ATA/1 ATA/2 ATA-2/3 ATA-2/4
IDE Drives and ATA Specifications

Data Transfer Rate
3.3 MBps 5.2 MBps 8.3 MBps 11.1 MBps 16.6 MBps

For IDE drives, ATA was the formal name chosen by the American National Standards Insti- tute (ANSI) group X3T10. It specifies the interface specifications for the power and data signals between the system board, the drive controller, and the drive. 

The manufacturer can use any physical interface, but must have an embedded controller that uses the ATA interface controller to connect the drive directly to the ISA bus.
The original IDE specification did not support CD-ROMs or hard drives larger than 528 or 504 MB. However, revisions of the specifications over the years have extended the capabilities to provide support for faster and larger hard drives. The following table describes ATA specifications.

Standard
ATA
ATA-2
ATA-3
ATAPI ATA-4 ATA-5
ATA-6
PIO
DMA
Ultra DMA 100

Description
The original ATA specification supported one channel, with two drives configured in a master/slave arrangement. PIO modes 0, 1, and 2 were supported, as well as single-word DMA modes 0, 1, and 2 and multi-word DMA mode 0. No support for non-hard disk devices was included, nor were block mode transfers, logical block addressing, and other advanced features.
Also known as the Advanced Technology Interface with Extensions. Western Digital’s implementation was called Enhanced IDE (EIDE). Seagate’s implementation was called Fast ATA or Fast ATA-2. Sup- ports PIO modes 3 and 4 and two multi-word modes, 1 and 2, all of which are faster than the modes supported by the original ATA specification. Support for 32-bit transactions. Some drives supported DMA. Could implement power-saving mode features if desired. Specification also covered removable drives.
Minor enhancement to ATA-2. Improved reliability for high-speed data transfer modes. Self Monitoring Analysis And Reporting Tech- nology (SMART) was introduced. This is logic in the drives that warns of impending drive problems. Password protection available as a security feature of the drives.
AT Attachment Packet Interface is an EIDE interface component that includes commands used to control tape and CD-ROM drives.
Also known as Ultra-DMA, UDMA, Ultra-ATA, and Ultra DMA/33. Doubled data transfer rates. Supported ATAPI specification.
The ATA-5 specification introduced Ultra DMA modes 3 and 4, as well as mandatory use of the 80-pin, high-performance IDE cable. Additional changes to the command set were also part of this specification. Supports drives up to 137 GB.
Supports Ultra DMA/100 for data transfers at up to 100 MB/second. Supports drives as large as 144 PB (petabytes), 144 million MB, or 144 quadrillion bytes.
Programmed Input/Output is a data transfer method that includes the CPU in the data path. It has been replaced by DMA and Ultra DMA.
Direct Memory Access is a data transfer method that moves data directly from the drive to main memory. Ultra DMA Transfers data in burst mode at a rate of 33.3 MB per second. The speed is two times faster than DMA.
Also known as ATA-100, this standard supports data transfers in burst mode at a rate of 100 MB per second.

Standard
Serial ATA
Serial ATA II
SCSI Standards

Description
Uses serial instead of parallel signaling technology for internal ATA and ATAPI devices. Serial ATA employs serial connectors and serial cables, which are smaller, thinner, and more flexible than traditional parallel ATA cables. Data transfer rates are 150 MB per second or greater.
Also known as SATA 3.0, SATA 3.0 Gb/s, and SATA/100. Provides data transfer rates of 300 MB/sec.

SCSI standards have been revised repeatedly over the years. The following table describes cur- rent SCSI standards.

SCSI Stan- dard
SCSI-1
SCSI-2
SCSI-3

2. Ultra-2  SCSI
   
3. Ultra-3  SCSI
   

Ultra-320 SCSI Ultra-640 SCSI

Description
Features an 8-bit parallel bus (with parity), running asynchronously at 3.5 MB/s or 5 MB/s in synchronous mode, and a maximum bus cable length of 6 meters, compared to the 0.45-meter limit of the Parallel ATA interface. A variation on the original standard included a high-voltage differential (HVD) implementation with a maximum cable length of 25 meters.
Introduced the Fast SCSI and Wide SCSI variants. Fast SCSI doubled the maximum transfer rate to 10 MB/s, and Wide SCSI doubled the bus width to 16 bits to reach 20 MB/s. Maximum cable length was reduced to 3 meters.
The first parallel SCSI devices that exceeded the SCSI-2 capabilities were simply designated SCSI-3. These devices were also known as Ultra SCSI and Fast-20 SCSI. The bus speed doubled again to 20 MB/s for narrow (8 bit) systems and 40 MB/s for wide (16-bit). The maximum cable length stayed at 3 meters.
This standard featured a low-voltage differential (LVD) bus. For this reason Ultra-2 SCSI is sometimes referred to as LVD SCSI. LVD’s greater immu- nity to noise allowed a maximum bus cable length of 12 meters. At the same time, the data transfer rate was increased to 80 MB/s.
Also known as Ultra-160 SCSI, this version was basically an improvement on the Ultra-2 SCSI standard, in that the transfer rate was doubled once more to 160 MB/s. Ultra-160 SCSI offered new features like cyclic redun- dancy check (CRC), an error correcting process, and domain validation.
This standard doubled the data transfer rate to 320 MB/s.
Also known as Fast-320 SCSI, Ultra-640 doubles the interface speed yet again, this time to 640 MB/s. Ultra-640 pushes the limits of LVD signaling; the speed limits cable lengths drastically, making it impractical for more than one or two devices.

Storage Area Networks
In addition to the technologies you see for increasing the drive space on workstations, many companies now implement technologies such as storage area networks (SANs). A SAN is a Fibre Channel network designed to attach storage devices such as drive arrays and tape librar- ies to servers. Most SANs use the SCSI protocol to communicate with these devices, along with the high-speed Fibre Channel interface. The advantage to a SAN is that you can easily move its storage from one server to another. In addition, you can configure a server to boot from a SAN, which means that if the server fails, you can quickly configure another server to use the SAN and thus replace the failed server.
Network-Attached Storage
In contrast to Storage Area Networks, network-attached storage (NAS) refers to storage devices that are dedicated storage servers. These devices enable users to access their data even when other servers are down. The drawback to NAS devices is that their performance depends on the speed of and traffic on your existing network.
Floppy Disk Drives
Internal floppy drives connect to the system board through a floppy disk controller. The drive can access data on the disk directly and spins at about 360 RPM. The form factor of floppy drives is usually 3.5 inches. Depending on the number of sectors per track on the disk, 3.5- inch floppy disks can hold 720 KB or 1.44 MB of data; the floppy drive can accommodate either disk capacity.

How Floppy Disk Drives Work
When you insert a floppy disk into a floppy disk drive:

1. The metal door on the disk slides open, revealing the Mylar disk surface.
   
2. The controller motor spins the floppy disk at about 360 RPMs.
   
3. A worm gear operated by a stepper motor (a motor that moves in fixed increments) moves the read/write heads (one on each side of the disk) to the desired track.
   

Write Protection
Floppy disks can be protected so that you cannot write over data on the disk. On the back side of the floppy disk, you will see a slider in the upper-left corner. If the slider is pushed down, it blocks the write-protect hole and enables you to write to the floppy disk. If the slider is pushed up and the write-protect hold is visible, you will not be able to write to the disk.
Tape Drive Types

Tape drives come in several formats.

How Tape Drives Work
While hard drives, floppy drives, and removable cartridge drives are direct-access devices, tape drives are sequential access devices. Rather than being able to go to a specific file directly, with a tape, you have to read past every file on the tape until you get to the one you want. For this reason, tape drives are typically used to store backup copies of information, as opposed to for live data access. When you insert a tape cartridge in a tape drive and perform a backup of files from your hard drive:

1. The computer reads the file system table on the hard drive, locates the files that you want to back up, and begins reading file data into RAM.
   
2. Data is then dumped from RAM to the tape drive controller buffer as memory fills.
   
3. The controller sends commands to the drive to start spooling the tape.
   
4. The capstan in the center of the supply reel turns the rollers in the cartridge. The belt around the tape and the rollers provide resistance and keep the tape taught and tight to the drive heads.
   
5. Data is sent from the controller to the read/write heads.
   
6. The tape is composed of parallel tracks. Data is written from the center out towards the edge on each pass. Holes in the end of the tape signal when the direction of the tape needs to be reversed. When it gets to the end, it reverses and moves out one track.
   

Optical Drive Types
Optical drives include CD and DVD drives. They can be connected via IDE, SCSI, USB, FireWire, or parallel interfaces. Some optical drives provide only read capabilities, while others enable users to write, or burn, data to optical disks. Optical drives can be internal or external. Internal optical drives have a 5.25-inch form factor. The following table describes optical drive specifications.

CD and DVD drives have varying characteristics and specifications. 

 

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