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study guides and tutorials. PC Troubleshooting |
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Common symptoms and problems associated with each module and how to troubleshoot and isolate the problems. CPU: A faulty or overheating processor will cause system crashes, lockups, and sudden reboots. Memory: Bad memory can cause a 'Memory test failed' error during POST, a 'Himem.sys detected unreliable memory' error during bootup, or a 'Parity error' during normal use. Floppy drive: problems can be caused by incorrect BIOS settings, a bad drive, a bad/poorly connected controller cable, or a bad I/O card respectively. Reversing a floppy drive's cable will prevent reading, but should not harm the drive. Monitor/video: Monitor settings are the most likely cause of a blank screen when the PC boots normally otherwise. Other causes can be a problem with the cable connection, monitor, video card, motherboard, processor, or RAM. Power supply: The entire power supply must be replaced if its internal fan goes dead. When replacing a power supply, pay attention to physical dimensions, the voltage and connectors are standardized. Fuses: are usually tested with a Volt/Ohmmeter (or Multimeter) set to Ohms. A good fuse will show 0 Ohms resistance. Multimeter use: If a multimeter is to be used on a circuit of unknown voltage, it should be set to the highest setting to avoid damaging the tool. Most good circuits will read 0 Ohms resistance. Basic troubleshooting procedures and good practices for eliciting problem symptoms from customers. To determine the cause of a problem, ask specific questions about the PC, its users, and its environment When troubleshooting a problem, try only one thing at a time, so it will be clear what resolved the problem BIOS (Basic Input Output System) - Built-in software that contains low level software for configuring the system's capabilities with hardware. System Assembly Basics Phillips and Flat-Head screw drivers are the most common tools needed for disassembly. Paper should be at hand for diagraming connections. Egg cartons are helpful in keeping screws organized. Expansion boards should be removed by gently rocking back and forth at each end. Red and blue stripes on ribbon cables indicate pin 1. Field replaceable units (or FRU's) are any computer parts that can be replaced without special equipment such as soldering irons. System Board Repair Mother boards, system boards, planar board, and main logic boards are all interchangable terms. Older XT planar boards used DIP settings for floppy configuration. Modern AT system boards use SETUP in the BIOS. SETUP should always be ran after motherboard replacement to reconfigure the system for customers. Controllers Controllers match speeds between sending and receiving devices, convert data between formats, and isolate the software from the hardware. A DTE device in general, is a device such as a computer or printer. A DCE device is a device such as a modem. A terminal sends the Ready To Send signal when it transmits to a DCE device such as a modem. A modem must have the Carrier Present signal before it is able to receive. RS232 is the standard for serial connections. DMAs (Direct Memory Access) work with the CPU, letting devices put data into memory rather than the CPU, therefore helping to speed transfer rates. Other Troubleshooting Tips: When replacing a power supply pay special attention to the physical characteristics, the voltage and connectors are standardized. Rom addresses, I/O addresses, IRQs, and DMA channels can all cause conflicts. IRQ conflicts are the most common conflict, because there are so few IRQs compared to the many peripherals that can be installed into a system. If a battery test fine after a boot configuration error, the most likely cause is the system board. Always carefully examine any shipped in merchandise before installation and powering the system on. Power Supplies |
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Hardware
Topics: Basic PC Overview
Operating
System Topics:
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all your tech book needs: Please Read -DISCLAIMER: Technology changes very rapidly. The information presented here was believed to be accurate at the time it was gathered. No claim is made that this information is up to date, or that it represents the current technology used today. |
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