UNIT I Hardware Maintenance and Troubleshooting
- 1. HARDWARE MAINTENANCE AND TROUBLESHOOTING UNIT - I Jeromy R Assistant Professor, Department of Computer Science and Applications, SRM Institute of Science and Technology, Ramapuram
- 2. Hardware Basics, Introduction to Computer Organization Computer: • An electronic device that accepts input, processing data, stores data, produces output Hardware: • Physical parts of the computer system • Machinery and equipment that can be seen and touched Firmware: • Low-level software stored on programmable memory devices • Treated like hardware but executed by software programs • Combination of software and hardware • Stored in chips such as: • ROM (Read-Only Memory) • PROM (Programmable ROM) • EPROM (Erasable Programmable ROM) Software: • Programs that tell the computer what to do • Examples: • Microsoft Word, Microsoft PowerPoint
- 3. The PC Hardware- consisting Input, Processing and Output Sections Input Devices: • Devices that input information into the computer • Examples: Keyboard, Mouse, Scanner, Digital Camera Output Devices: • Devices that output information from the computer • Examples: Monitor, Printer CPU (Central Processing Unit): • Also known as the Microprocessor or "The Brain" of the Computer • Executes instructions at high speed, measured in MHz Popular Processor Brands: • Pentium, Celeron, MAC, AMD, Cyrix
- 4. Overview of System Components: Motherboard components Input Unit: • Accepts data via devices like mouse, keyboard, scanner • Converts user data to machine-readable binary form • Sends data to main memory for processing • Bridges communication between user and computer CPU (Central Processing Unit): • The "brain" of the computer • Performs all arithmetic and logical operations • Comprises: • ALU (Arithmetic Logic Unit): Handles calculations and logical comparisons • CU (Control Unit): Directs operations, generates control signals
- 5. Overview of System Components: Motherboard components Memory Unit: • Stores data temporarily or permanently • Primary Memory (RAM): Temporary, fast access, volatile • Secondary Memory (Hard Disk): Permanent storage, non-volatile • Works closely with CPU for efficient data access Output Unit: • Displays processed data via monitor, printer, projector • Converts binary output into human-readable form • Produces both soft and hard copies
- 6. Overview of System Components: Motherboard components Motherboard: • Main printed circuit board in a computer • Connects CPU, memory, storage, and peripherals • Distributes power and allows communication between components Key Components on the Motherboard: 1. Processor Sockets • Houses the CPU • Types: PGA (Pin Grid Array), LGA (Land Grid Array) 2. Memory Sockets • Slots for installing RAM • Types: SIMM, DIMM, RIMM 3. Chipset • Manages data flow between CPU, memory, and peripherals • Determines motherboard capabilities (CPU type, memory type/speed, USB slots, etc.)
- 7. 4. Cache Memory • Small, high-speed memory near the CPU Types: • L1 – Inside CPU (8–64 KB) • L2 – Between CPU and RAM (256–512 KB) • L3 – On motherboard or within CPU (shared among cores) 5. BIOS (Basic Input/Output System) • Firmware that initializes hardware during boot • Handles POST (Power-On Self-Test) and OS loading 6. Clock Generator & RTC (Real-Time Clock) • Provides timing signals for system synchronization • RTC keeps time even when power is off 7. Super I/O Controller • Manages legacy devices: floppy disk, serial ports, keyboard/mouse interfaces 8. Form Factor • Physical layout standard (e.g., ATX, Mini ATX, NLX) • Determines compatibility with cases and power supplies Overview of System Components: Motherboard components
- 8. Identifying Type of SMPS: Circuit Diagram & Pin Assignments What is SMPS? • SMPS (Switched Mode Power Supply) converts high-voltage AC into regulated DC • Compact, efficient, and supports multiple voltage outputs (e.g., 5V, 12V, 24V) • Uses high-frequency switching and feedback control Basic Components: • TNY267 IC: Core switching controller • Flyback Transformer (EE20): Steps down voltage • Optocoupler (e.g., EL817): Provides output feedback to regulate voltage • Rectifier & Filter: Smooths the DC output • PWM Control: Adjusts pulse width to maintain stable output
- 9. Pin Assignments (TNY267 IC): 1. BP (Bypass): Connects to capacitor for internal circuitry 2. D (Drain): High-voltage input (connected to transformer) 3. S (Source): Ground reference and power return 4. EN/UV (Enable/Under Voltage): Enables IC and senses undervoltage Working Principle: • AC input → Rectified to DC → Switched at high frequency • Transformer steps down voltage • Feedback via optocoupler regulates output by adjusting PWM • Ensures minimal output fluctuation regardless of input/load changes Identifying Type of SMPS: Circuit Diagram & Pin Assignments
- 10. Knowing working of smps input and load requirement mother board of pc Input Requirements: • Accepts wide AC range: 90–250V • Requires input filtering (to suppress spikes/surges) • High-voltage rectification occurs in the first stage Load Requirements: Provides multiple DC rails: • +12V: CPU, fans, disk drives • +5V: Legacy devices, USB • +3.3V: RAM, chipsets • -12V, -5V: Serial ports, audio circuits (rare now)
- 11. SMPS: Working, Requirements, Interrupts, I/O, Circuit & Pin Details Interrupts (Priority Management): • Devices send interrupt signals to CPU • Software Method (Polling): CPU checks devices in order of priority • Hardware Method (Daisy Chaining): • Devices connected in series • Highest priority device blocks the chain • Passes interrupt vector to CPU I/O Techniques: • Manages data transfer between CPU and peripherals • Interface handles: • Data rate mismatches • Code conversion (serial ↔ parallel, digital ↔ analogue) • Control and timing signals • Synchronizes I/O operations and buffers data
- 12. Device Interconnection, Virtual & Cache Memory Interconnection Between Devices: • Devices connect to the motherboard via ports and headers • Common interfaces: • ATX power connector (24-pin) • IDE/SATA for storage • PS/2 / USB for keyboard/mouse • Serial/Parallel for legacy I/O • Headers & Ports: Bridge between internal components and external peripherals Cable Polarities: • Ensure correct orientation of connectors (marked by notches or color codes) • Red wire usually indicates pin 1 in ribbon cables • Incorrect polarity can cause boot errors or hardware damage • Polarized connectors prevent incorrect insertion
- 13. Virtual Memory: • Logical extension of RAM using hard disk space • Allows execution of programs larger than physical memory • OS swaps data between RAM & disk (paging) • Advantages: • Allows multitasking • Boosts memory usage efficiency • Disadvantages: • Slower than physical RAM • Frequent swapping can reduce performance Cache Memory: • High-speed memory between CPU and RAM • Stores frequently accessed data/instructions • Levels: • L1 (within CPU, 8–64 KB) • L2 (external or internal, 256–512 KB) • L3 (shared, up to several MB) • Advantages: Faster access than RAM • Disadvantages: Expensive, small size Device Interconnection, Virtual & Cache Memory
- 14. Microcomputer Concepts, Multitasking & Multiprogramming Microcomputer Concepts: • Definition: A small, low-cost computer with a microprocessor as its CPU • Components: CPU, memory, storage, input/output devices on a single board • Examples: Desktop, Laptop, Tablet, Smartphone, PDA • Uses: • Personal computing • Education & learning • Medical & industrial applications • Features: • Compact & affordable • Runs common OS (Windows, macOS, Linux) • Designed for single-user operation
- 15. Microcomputer Concepts, Multitasking & Multiprogramming Multiprogramming: • Concept: Multiple programs loaded into memory simultaneously • CPU executes one while others wait (e.g., for I/O) • Purpose: Maximize CPU utilization • Advantages: • Increases system throughput • Reduces CPU idle time • Disadvantages: • Complex scheduling • Requires OS with job management capabilities
- 16. Microcomputer Concepts, Multitasking & Multiprogramming Multitasking: • Concept: Multiple tasks/processes executed seemingly at once • CPU switches rapidly between tasks (time slicing) • Types: • Preemptive (OS controls switching) • Cooperative (tasks voluntarily yield control) • Advantages: • Improved responsiveness • Allows interactive user sessions • Disadvantages: • Needs more memory • Overhead from frequent context switching