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CMOS and BIOS The system BIOS is the set of instructions that is written on a ROM chip on the motherboard. The CMOS is user-configurable settings that the BIOS uses to recognize hardware. The system date and time maintained In the CMOS when the system is turned off. To improve read performance, enable BIOS shadowing. Shadowing a BIOS copies the BIOS instruction set to RAM, where it can be read quickly. Your system may access the BIOS thousands of times a second when accessing hardware. Flashing the BIOS If you need to upgrade the BIOS for a particular motherboard, know the Manufacturer and Model of the motherboard to ensure you have the right update. Upgrading the BIOS involves booting from a disk, and using a program to load new BIOS software from an image file. The process is known as FLASHING the BIOS. If a BIOS does not support flashing but needs to be upgraded, it is necessary to replace the CMOS chip. This is more common on older (286-386) motherboards. Write down all BIOS settings before flashing the BIOS, since flashing the BIOS usually clears all CMOS settings. After flashing the BIOS, you will need to set the date and time. Note: If the Power goes out while updating the BIOS, the Motherboard may never boot again. A failed motherboard battery will cause CMOS settings to be lost. The BIOS settings are maintained in ROM, and are not lost with battery failure. Typical BIOS Settings Settings may differ between different motherboards and manufacturers, but the following settings are found in the CMOS configuration of most ATX motherboards: Standard Settings: Hard Disks (Heads, Sectors, Cylinders, LBA mode) – Auto-detect Advanced Settings: Boot Order (CDROM, Floppy, HDD), Video PCI/AGP settings. PCI Plug and Play: IRQ assignments for PCI ports, and IRQ availability Peripheral Devices: COM Port settings and LPT port settings, USB port settings. You can find the BIOS version ID on the main menu of the BIOS setup, and often in the beginning of the system boot process (on the POST screen). You can set a password on the BIOS to protect settings. If you forgot or lost the BIOS password on a computer most will have a CMOS jumper, which clears all of CMOS, including the password. Some computers will allow you to clear the CMOS by booting while holding down the CTRL key. The CMOS will also often have Advanced Power options, which allows the operating system to take advantage of power saving features. There is no setting for a screen saver. Bootup A video card has its own BIOS, which will often run before the system BIOS to initialize the video card. SCSI adapters also will have their own BIOS, but generally run the BIOS after the system. The ROM BIOS provides the first instructions available when a computer is powering up. The BIOS startup includes a POST (Power On Self Test): Minimum hardware components required to pass POST: CPU, RAM, Video Card The initial POST does a cursory check of the listed hardware, looking to see if all of the hardware needed to boot is present. The POST will identify any hardware that fails at startup, but would not identify a CPU or Memory that fails when the system heats up. POST checks and error code ranges:
The above POST errors are not all possible post errors. They are the major families of post errors that you will need to memorize for the test. Post errors will be a number in the family. Example:
For a more complete list of post errors, go here: http://www.toggit.com/library/hw/post.htm After POST, BIOS plug n play Consults ESCD (Extended System Configuration Data) to determine if resources are available and needed. ESCD provides Plug and Play capability to PnP components. In Advanced CMOS settings, you can specify which device(s) should be used to boot the system. When the BIOS completes the POST and PnP setup, it will report status and turn over control of the boot process to the specified boot device. Often you will have to change the boot order in the BIOS to have a computer boot from floppy or CD ROM. Many BIOS will allow you to specify multiple boot devices. The computer will check each device for bootable media. Mainboard For this test, you will have to be able to identify major motherboard components by sight. Learn to identify components from the photograph as well as from the cryptic drawing.
You will also need to identify typical ports by sight:
A. 5 pin DIN Keyboard connector (found on AT and XT
motherboards)
Memory Unplug the PC when installing memory. Having the PC off is not enough on ATX motherboards, as power is still applied as the system waits for an 'on' state. 72 pin SIMMs must be installed in pairs. 168 Pin DIMMs are installed one at a time. Learn to identify these types of memory formats: * Chip placement may vary, observe notches and pins
A. 30 Pin SIMM B. 72 Pin SIMM C. 144 Pin SODIMM D. 168 Pin DIMM
Advantage of using ECC (Error Checking and Correction) memory Corrects Cache errors. Process of refreshing memory is Recharging or reenergizing the registers. When RAM is installed correctly, the system will recognize it. There is no BIOS or Jumper setting for installing RAM. Hardware IRQs are used by hardware to allow them to send an interrupt request to the CPU, or for the CPU to signal the hardware. The I/O address is the address in memory that the CPU and hardware device can use to exchange data. You need to know the default IRQ settings:
There are many addresses to know, but these are the ones you need to know for the test:
A device must have IRQ setting in order to interrupt the CPU. When the hardware device signals the CPU on the interrupt, the device can share data with the CPU in memory at the appropriate I/O address. Most ISA devices are not Plug and Play. Most PCI and USB devices are Plug and Play. Components that are not Plug and Play have physical jumpers or special configuration software that must be used to configure the IRQ, I/O address, and for some devices the DMA channel. Example: when installing and ISA Network Card, jumpers would be set for IRQ (9, 10, 11, etc...) and I/O address (usually 300h). When installing PCI device you can check IRQ availability Motherboard BIOS. Most motherboards will allow you to configure IRQ assignments for PCI slots, or allow for automatic configuration. Assignemnt order of IRQs: 1. Hardware assigned (jumpered) non plug and
play devices. CPUs
Pentium MMX: Multi Media
instructions were added for performance and the
L1 cache size increased to 32KB. See the Webopedia detailed CPU chart Read up on SIMD Extentions at x86.org (Pentium III)
A ZIF socket (Zero Insertion Force) is any CPU socket that has a handle on one side to release the CPU form the socket. Older CPUs required pressure on the CPU to install. ZIF helps with inserting and removing CPUs? Intel's Single Edge Contacts (SEC) design used on Pentium II and Pentium III processors includes the CPU, L1 Cache, and L2 Cache. Socket 7 CPUs (and earlier) used L2 Cache on the motherboard. Level 1 Cache (L1 Cache) is the cache memory that is built in to the processor. L1 is also called primary cache. Level 2 cache (L2 Cache) is cache memory that is external to the microprocessor. In general, L2 cache memory, also called the secondary cache, resides on a separate chip from the microprocessor chip. Although, more and more microprocessors are including L2 caches into their architectures, it is still technically external to the CPU. A CPU speed is a combination of Bus Speed and a Pipeline multiplier. For example: The motherboard speed setting for a Pentium-200 is 66 Mhz multiplied by 3. A Pentium II 450 is a bus speed of 100Mhz multiplied by 4.5. Video There’s 15 pins are on a VGA connector (See connectors above) Memory address range is reserved for VGA video card C000-C7FF. VGA mode offers a resolution of 640x480. SVGA video mode offers a video resolution of 800 into 600. Most video cards offer even higher resolution. Resolution and color capabilities of a video card are determined by the memory of the video card. For instance: you need 4MB video RAM to display 1024 into 768 at 24bit color. AGP accelerated graphics port of an ATX motherboard which allows a video card to access main memory directly. The AGP Bus is 32bits wide and based on PCI technology. The AGP slot can only be used by a Video card. Types of video RAM? (Three) VRAM. WRAM. SGRAM. DRAM? LRAM? The Dots Per Inch (DPI) measurement on a monitor is a measurement of the detail level of the monitor. For instance: a 28 dot pitch (DPI) refers to .28 millimeters between color dots on the monitor. Energy star compliant monitor Switches to low power status when signal static. The Video Refresh Rate is the time it takes the monitor's electron beam to paint all of the lines of the screen once. The picture tube in a standard monitor is referred to as a Cathode Ray Tube (CRT). A CRT requires extremely high voltage, and should not be repaired onsite. Monitors should only be repaired by technicians trained to work on CRTs specifically. Drives Floppy: The Floppy drive letter is assigned by cable position. The floppy drive before the twist in the cable is drive B, the floppy disk after the twist in the cable is drive A. A "601" error during POST indicates Floppy driver error. If the floppy disk. IDE Hard Drives and CD ROMs Each IDE controller can host 2 IDE devices; one master and one slave. So a maximum of four IDE devices could be connected on most systems. Two IDE controllers are typically built into an ATX motherboard, and Pentium AT motherboards. A standard IDE connector has 40 pins. Connect the bootable drive to Either the first or the second connector from the primary IDE controller. an ATA/33 cable has 40 wires. An ATA/66 cable has 80 wires. Hard Disk drive letter is assigned when partitioning. An IDE drive can be set by a specific connector by Jumping for cable select. One hard drive and CD-ROM: Master drive on the secondary IDE channel. Set one drive a master and the other a slave when installing a second IDE. Hardware settings on the device determine which IDE device is master and slave. Two IDE devices can connect on a single IDE channel? Hard drive Size (Head, Cylinders, Sectors) values are held in the CMOS. LBA is a type of IDE translation, where the CMOS values are different from actual drive parameters. LBA mode is necessary fro drives over 502 MB. When replacing a hard drive change check drive select jumper (master or slave) and/or Cable orientation (which location the drive is on the cable if it's cable select) Valid translations in the hard drive settings in the CMOS: CHS, LBA, Extended TRA? SCSI Hard Disks, CD-ROMS, and Tape Drives Each SCSI device is configured with a unique ID to work on the same channel. ID is unique about each device on a SCSI chain, and is usually set by configuring jumpers on the SCSI device. Each SCSI chain must be terminated on each end. Some drives may have termination jumpers, otherwise a physical terminator must be put in place. If a SCSI chain is using internal and external devices on the same controller, one terminator will be on the outside of the computer, and one internal (the controller would be in the middle of the chain). Highest address on a three-position SCSI-2 jumper block is 7. This means that up to seven devices can be attached to a SCSI-2 controller. Command queuing features of SCSI-2 enable device to accept multiple instructions. SCSI ID reflects a binary number. For instance: An ID of 3 on a three-bit jumper block on a SCSI hard disk drive: 011 A SCSI adapter can plug into a PCI, EISA, VL-BUS expansion slot. SCSI devices are usually Hard Drives, CD-ROMs, and Tape Devices, though some other devices use SCSI also.
Fiber channel SCSI can achieve a speed of 100 Mbps over a ribbon cable Priority settings given to the SCSI ID number: 0 is the highest, 15 is the lowest. General For any type of drive, the seek time is the average time that it takes for the hard disk heads to move from one location on the platter to another. A seek time of 8ns (nanoseconds) is faster than a seek time of 12ns. IDE controller fails Install an IDE card. Replace the motherboard. "Bad or missing operating system”: Missing / corrupt boot sector or Flop in Dr IO ports Serial There are 9 or 25 pins are on a serial port connector. There are 25 pins on a parallel port. IEEE 1284 is the standard parallel cable used with most printers. Printer cable has a DB-25 connector on the PC end, and centronics connector on the printer end. A COM port is what the operating system calls the serial ports. You usually have up to 4 COM ports: COM1 - COM4. The RS-232 interface is the standard for the PC's serial interface. Essentially, RS-232 means serial port. Use the connectors graphic at the beginning of this document to become familiar with standard serial and parallel port connectors. Know the IRQ and memory assignments from the following chart:
Either COM1 and COM3 use IRQ 4. Either COM2 or COM4 use IRQ 3 Parallel There are three different operations modes for your parallel ports: SPP, EPP, and ECP. These mode settings are usually set in the CMOS settings under Peripheral Devices. SPP (Standard Parallel Port) is a one direction standard parallel port. EPP (Enhanced Parallel Port) is used for bi-directional printing capabilities. This is the setting used for connection to most printers. ECP (Extended Capabilities Port) is used to connect external devices (like drives) to a parallel port. ECP uses DMA, EPP doesn’t. ECP has the highest Parallel throughput over SPP, EPP. External storage devices like tape drives, CD-ROMS, Zip drives, and External hard disk drives often connect to a parallel port. The port should be configured as ECP to accept the device. A parallel port communicates information 1 byte (8bits) at a time to a device. Parallel is NOT capable of full-duplex transmission in any mode. Centronics (36-pin) D-shell is used for a parallel connector on the printer end
*Note: The IRQs listed are the default IRQs used for these ports. Since IRQ 5 is typically used by a sound card, LPT2 may wind up using almost any availale IRQ. LPT3 would also use any available IRQ. Each parallel port is linked to a logical printer port (LPT). An LPT port is what the operating system calls the Parallel ports. You can have up to 3 parallel ports: LPT1, LPT2, and LPT3. USB / Firewire USB is the newest type of printer interface, and is also typically used for connecting almost any other type of device: digital cameras, scanners, mice, keyboards, external drives, PDAs, networking components, musical instruments, speakers, and thousands more... Learn to spot a USB connector by sight. Advantages of the USB: Speed. Ease of configuration. Expansion On a computer, all USB ports branch out of one USB Root controller. The USB root controller is assigned an IRQ (usually done in CMOS). So all USB devices connected to a computer will use only 1 IRQ! USB devices are hot-swappable, which means that they can be added or removed while the system is running. For example: You can plug a USB mouse in while the computer is running. The USB port can supply a minimal amount of power for a device, though most larger devices (like printers or scanners) will have their own power connections. Maximum number of USB devices that can be connected to a PC is 127 IEEE1394 (Firewire) is faster than USB, uses different connectors, and only supports a maximum of 63 devices. Peripherals Analog loop back test checks the transmitter and receiver of a local modem A mouse will typically use a PS/2 connector, and sometimes a USB connector, and more rarely, a serial connector. If you are replacing a mouse, check the connector type. A digital camera most often use RS-232 Port,USB Port to connect to a computer. A digital video camera typically use IEEE 1394 (firewire) over USB because of speed. Modem A standard telephone line uses an RJ-11 connector to plug into a modem. When accessing a modem from terminal mode, you can send commands directly to the modem. The commands start with AT, and include other command letters. For instance: ATZ command used to reset your Modem's configuration, ATDT 555-1234 would cause your modem to dial the number 555-1234. The modem will not dial out: Cable is not plugged in. The phone line is defective? Phone, Fax machine can cause interference with a modem connection Laptop Since manufacturers are constantly trying to design better, smaller, lighter laptop computers, there are very few interchangeable parts between computers. For instance, when replacing motherboard in a laptop, you must match the manufacturer and model number exactly. Another motherboard would not physically fit. Connector to docking station is Manufacturer and model specific. Newer laptops use SODIMM as the memory architecture, which makes memory interchangable, and most laptops use a 2.5 inch IDE hard disk, which is also interchangable. For expansion cards, laptops use the PCMCIA standard (PC Cards). PCMCIA cards are hot swappable cards.
Typically, you can fit only 1 Type III PC card in a laptop, as they are twice as thick as other PC cards. Read the PCMCIA.ORG FAQ LCD on a laptop powered by Low voltage DC. Replace Adjustment Switch if the brightness or contrast adjustments were malfunctioning on a Laptop? LCD Display too expensive A notebook computer that has a Ni-Card battery continually requires recharging more often than when the notebook was first published called Memory effect A technician is working on a standard laptop with two PCMCIA slots available for add on boards. The system currently has a type II PCMCIA modem installed and will need to add a Type III PCMCIA modem card. Remove Type II PCMCIA card to install Type III card. Power
Use Multimeter to test the power connector from PS. When replacing a power supply what you must observe Wattage. If the fan in the power supply stops working or is noisy, replace the entire power supply. Power supply fans are not considered to be serviceable parts. Higher Amperes most likely to cause serious injury or death Electrical sag: Computer suddenly restarts and lights flicker There is danger from a power surge when power is restored after a power failure . When installing an AT power supply Black, Black Printers A parallel printer cable has a DB25 connector on the computer end, and a Centronics 36 connector on the printer end. Most printers today connect to the computer using USB, though many still come with parallel port connectors as well. Laser jet printer speeds are measured in pages per minute (PPM). Dot matrix printers are measured in Characters per second (CPS) printer self test page? panel on printer. printer properties settings. Dot Matrix Printers The dot matrix printer uses pins to strike the print ribbon to form an image. The dot matrix printers tend to be loud and slow, but are used when printing forms that need to be filled out with carbon paper or carbonless multi-copy paper. Dot Matrix printers are also used when tractor-feed paper needs to be used (like when using Continuous Forms). Dot Matrix printers generally come with 9 or 24 pins on the print head. Standard paper quality dot matrix printer has 9 pins, and a Letter quality dot matrix printer has 24 pins. Defective print head on a dot-matrix printer may cause only the bottom half or top half of the characters to be printed. If a dot matrix printer is patchy, faint or uneven replace the ribbon Ink Jet PrintersClose nozzle gate keeps ink from leaking out of the cartridge on ink jet printer Ink jet printers use special miniature nozzles to spray ink onto the paper. When not printing small "valves" keep the ink from leaking out. After installing a new ink-jet cartridge, you should run the printer alignment program that comes with most ink-jet printer drivers. Laser Printers Toner cartridges disposed off by Recycled by manufacturer. The proper storage for OPC (Organic Photoconductive) drums is a cool and dark location. Laser printer should not be plugged into a standard UPS?
In the fusing stage of the laser printer melts the written image to the paper. When you service the laser printer avoid touching Fuser because it is hot. Ozone filter (Google) vacuumed or replaced during maintenance on a laser printer? Printer Errors: Malfunctioning pick up rollers is the most common problem with the paper tray. Smooth pickup rollers common cause of wavy image on paper. Also, under humid conditions, paper can stick together and cause the computer Duplexer allows you to print on both sides of the paper. Why would the back of page be dirty on a Laser printer? Contaminated fuser Trouble The computer will not boot from the floppy drive. The boot sequence in the BIOS is incorrect. The floppy drive is defective. Suspect bad sectors: Run Scan Disk with the thorough option. Your customer decided to install a new USB printer on his Windows 95 computer but cannot get the computer to recognize it. What is the most likely cause? USB supplement for Windows 95 is not installed. Ask a user when gathering information about an issue: When did this issue begin? Ask a user: What were you doing when the issue began? A new 128 MB memory chip has just been installed in a Pentium 3 laptop. When the system is booting up the first time, only the original 64 MB of RAM is visible. The new memory chip is not seated properly Dead computer was working fine the day before? Check the AC outlet for voltage Virus risk factor: a floppy disk from friend or downloaded file from internet A bent pin on a three row DB-15 male connector plug could cause problems with Monitor Hardware How should you open the tray on an inoperative CD-ROM drive pin? FRU (Field Replaceable Units)? RAM ROM Choose three) ? Upkeep Better system cooling benefit of cleaning the inside of the computer A failed processor fan would cause CPU damage System lockups Canned air or Small brush can be used to clean the inside of a computer Purpose: Line conditioners, Battery backup devices, Surge Sup./ Strips How should you clean the CD-ROM media? Wipe it using center to edge motions You should you have slot covers installed on a computer to Improve Air flow Uninterruptible power supply is also known as Battery Backup? Class C extinguisher should be used to extinguish a computer fire Clean the mouse if the mouse pointer is not moving correctly across the screen
other-firewall typically stored on Hard disk Windows cannot detect the jumpered modem: IRQ conflict. What is the problem? PS/2 mouse - ATX keyboard have same looking connector SCSI scanner, Parallel printer may have the same looking connector? (Choose Networking Which cable types can network two computers? UTP Parallel Serial? Firewire? One personal digital assistant to another PDA: IR? A Network Interface Card (NIC) provides computer with a physical and electrical connection to a network. Half Duplex means that the network equipment cannot send and receive at the same time. The maximum distance for a 10BaseT segment is 100 meters Category 5 is the minimum cable type 100BaseTX specifies? 10BaseT cable is most likely in use with RJ-45 connectors The 10BaseT specifies Category 3 minimum cable typeEthernet 10BaseT uses Star type of physical topology? Cross over cable connect two computers in network RJ- 45 and Category-5 Cable. Crossover cable Connect two network devices without a Hub Repeater is used to extend the 10Base2 network beyond the maximum distance The 10Base2 uses which of the following connectors? BNC What are causes of problem on 10Base2 network? Faulty T-connector or terminator Logical Bus topology does 10Base2 use? Maximum distance for a 10Base2 segment? B. 185 meters A NIC that has an ST or SC connector on it is Fiber Optic Protocol is the common language that computers use to talk with one another. Set of rules used to transmit data from one computer to another called Protocol TCP/IP supports: Ethernet, Token Ring, Modem dial-up TCP/IP requires unique addressing through software configuration? Peer to peer: Limited number of computers acting as both client and a server. With respect to the interface network card, 10/100 refers to Megabits per second. Windows uses Workgroup name in a peer to peer network? IRQ; MAC address; I/O Address settings are set in EEPROMS on a NIC? Define: 802.11b Fiber cable is the MOST expensive to implement? The protocol HTTP answers a request to an Internet site? You are installing an IPX client connecting to a file server. The client can not communicate with the server, but other workstations can. The workstation can communicate with other nodes on the same network through IP. The frame types are different between the client and file server.
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