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Introduction to a Typical PC. Computer Service & Repair Chapter 1. Key Terms. Computer : An assembly of electronic modules that interact with programs to create, modify, transmit, store, and display data. Data : Information (text, graphics and sound) Digital vs. Analog
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Introduction to a Typical PC Computer Service & Repair Chapter 1 Computer Service and Repair Chapter 1
Key Terms • Computer: An assembly of electronic modules that interact with programs to create, modify, transmit, store, and display data. • Data: Information (text, graphics and sound) • Digital vs. Analog • Digital: Data represented by a series of simple on/off switches. • Analog: Data represented by varying voltage levels (think dimmer switch) Computer Service and Repair Chapter 1
Key Terms Computer Data Codes: • Binary Number System: • Number system consisting of 1’s and 0’s • Perfect for on/off digital systems • Hexadecimal Number Code: • Number system consisting of 16 characters • Matches hardware systems (6,16,32,or 64 wide) • ASCII: • American Standard Code for Information Interchange • First attempt to standardize computer character codes Computer Service and Repair Chapter 1
Key Terms • Bit (b): Short for “Binary Digit” 1 or 0 • Bytes (B): eight bits • Words: the total amount of bytes a computer can process at one time • Varies from computer to computer • 1 to 8 bytes Computer Service and Repair Chapter 1
Key Terms Serial vs. Parallel Data Transfer • Serial transfer: • Data is sent through a port one BIT at a time • Used due to limited capacity of media (phone line) • Slow • Parallel transfer: • More than one Bit is sent side by side through a port • Used on internal bus (RAM to CPU) • Fast Computer Service and Repair Chapter 1
Key Terms Computer Numerical Values: • Storage is expressed in Bytes • Speed is expressed in Bits • Uses Metric Prefix names • Used base 2 not base 10 • i.e. Kilo is 210 not 103 • Nano = .000 000 001 (Billionth) • Milli = .000 001 (millionth) • Kilo = 1,000 (thousand) • Mega = 1,000,000 (million) • Giga = 1,000,000,000 (billion) Computer Service and Repair Chapter 1
Outside the Computer Case • Workstation consists of a computer, input device and output device • Computer is a case that contains: motherboard, CPU, memory, hard drive & etc. • Input device typically keyboard and mouse • But there are others • Output device typically monitor, printer, & speakers • But there are others Computer Service and Repair Chapter 1
Outside the Computer Case • Peripherals are optional pieces of equipment used to display or input data • Monitor • Printer • Keyboard • Scanner • Barcode reader • Etc. • Cases contain and protect electronic parts • Tower • Desk top • Mini tower • Laptop • Notebook Computer Service and Repair Chapter 1
Outside the Computer Case Exterior Connections • Mini DIN • Connections used for keyboard and mouse • May or may not be interchangeable • FireWire (IEEE-1394) • More often seen on Apple computers • Hot swap can change device while PC is running • USB Universal Service Bus • Eliminates need to open case to connect devices to computers main bus • Hot swap Computer Service and Repair Chapter 1
Outside the Computer Case • Device Bay: drive bay designed to hot swap drives. Bay is prewired with FireWire or USB • RJ • RJ 11 (Modem) Phone connection • RJ 45 (Ethernet) NIC connection Computer Service and Repair Chapter 1
Outside the Computer Case • DB “D” Shaped connection • 9, 15, or 25 pins • Sound Card DB (game port) • HD15 Monitor connection • Replaced by USB • VGA • HD 15 DB Port • Analog Port • DVI & HDMI (display ports) • Digital ports Computer Service and Repair Chapter 1
Outside the Computer Case • SATA • Data connection to external SATA device • Does NOT supply power to external device • Power eSATA • Same as SATA but supplies power to external device Computer Service and Repair Chapter 1
Lab 1 Identify Ports Computer Service and Repair Chapter 1
Inside the Case • CPU: Central Processing Unit • Brain of the computer • Silicon chip • Millions of Transistors (on/off switches) • Controls actions of computer components • CPU is controlled by Software • Intel, Celeron, and AMD Computer Service and Repair Chapter 1
Inside the Case • Power Supply • Converts 120 AC power from wall outlet to DC • Usually 3.3, 5, or 12 volts DC • Lower DC voltage needed to avoid damage to Components Computer Service and Repair Chapter 1
Inside the Case • Hard Drive: Internal Drive • Consists of several disks sealed in a sealed box • Data and programs are stored as magnetic patterns • Connected to power supply and motherboard Computer Service and Repair Chapter 1
Inside the Case • Motherboard • Rectangular printed circuit board • Distributes power and digital signals (data and instruction) • This electrical system of pathways is called the computer bus Computer Service and Repair Chapter 1
Inside the Case • RAM (random access memory) • Stores programs loaded from hard drive • Volatile memory system (data lost when power is turned off) • Increasing RAM most common upgrade Computer Service and Repair Chapter 1
Inside the Case • Firmware: • Hardware specific software required to boot the computer and support communication operating system and hardware devices • Translates commands into actions • Found on mother board and in many devices • Includes SETUP utility • Once permanently burned onto “ROM chips” • Now on EEPROM (electronically erasable programmable ROM) Computer Service and Repair Chapter 1
Inside the Case • Driver: a small software program written specifically for hardware • CMOS: (complementary metal oxide semiconductor) it is where the setup utility stores date, time, and hardware information. • BIOS small 64kB firmware • There is no standard BIOS • May cause compatibility problems Computer Service and Repair Chapter 1
Inside the Case • Battery: • Supplies voltage to CMOS • Without battery system would lose date, time and information about hardware when power is turned off Computer Service and Repair Chapter 1
Inside the Case Expansion Slots: Expansion cards: Computer Service and Repair Chapter 1
Inside the Case • Cooling Fans • Excessive heart damages electronic components • Cables: • SATA Serial ATA • PATA Parallel ATA Computer Service and Repair Chapter 1
Lab 2 Identify Components Computer Service and Repair Chapter 1
How the Major Parts Work Together • Power turned on. Power supply converts AC to DC and fan turns on • Firmware is activated and performs a POST (power on self test) checks components to ensure they are working properly. • After Firmware checks system Operating system is loaded and takes over. • The CPU now waits for activity generated by mouse, keyboard, or other input device. The CPU is checking for commands thousands of time per second Computer Service and Repair Chapter 1
How the Major Parts Work Together • Once user selects a program icon (lets say WORD). The software represented by icon is activated and shares control of the CPU. • Some typing is done. • When WORD saves the operating system takes over with the firmware. • Operating system interprets the command and translates it to a set of instructions that the firmware can interpret. Computer Service and Repair Chapter 1
How the Major Parts Work Together • The firmware translates the instructions to the storage media (usually the hard drive) • The hard drive activates its motor and actuator arm then writes data to next available sector. • Control is then returned to WORD (unless an error occurs (i.e. disk full or un readable) • rinse and repeat… Computer Service and Repair Chapter 1
Dangers to / from Computers • ESD: Electrostatic Discharge • Static Discharge • ESD can Destroy miniature circuits inside a computer chip • Anti-static Wrist Strap Prevents ESD • Or just touch metal in the case before touching anything inside the case • Shipped in Anti-static bags Computer Service and Repair Chapter 1
Dangers to / from Computers • EMI: Electromagnetic Interference • Damage to components caused by magnetic fields • Most common source of magnetic field magnetic tools (screwdrivers) • Less reliance on magnetic media and shielding have minimized potential damage. • But why risk it avoid magnetic tools . Computer Service and Repair Chapter 1
Dangers to / from Computers • RFI: Radio Frequency Interference • Radio Waves • Normally not a problem because radio waves tend to be very weak. • Wireless networks may act erratically or fail • Microwave ovens • Baby monitors • Cell phones • Cordless phones Computer Service and Repair Chapter 1
Dangers to / from Computers • Physical Safety • Cables (tripping hazard) • Floor runner/tape • Avoid rugs (fire hazard) • Loose Clothing • Weight • 50 LBS max. • OHSA (Occupation Health and Safety Administration Computer Service and Repair Chapter 1
Dangers to / from Computers • Fire Safety: • Class A Ordinary materials (paper and wood) • Class B Flammable Liquids (gasoline oil) • Class C Energized Electrical Equipment • Class D Combustible Metals (potassium) • Class K Kitchen Fires (cooking grease) • Chemical Safety: • CRT Monitor (lead) • Some TONER (check MSDS) Computer Service and Repair Chapter 1
End of Chapter 1 Any Questions? Ready for a test? Computer Service and Repair Chapter 1