IT 141 - Troubleshooting a System Unit.pdf

IT 141 Troubleshooting a System Unit Prepared by: Naycer Jeremy G. Tulas [email protected] 09129412101 https://www.facebook.com/naycer.tulas Common Issues with a System Unit System Unit will not turn on Bef...

IT 141 Troubleshooting a System Unit Prepared by: Naycer Jeremy G. Tulas [email protected] 09129412101 https://www.facebook.com/naycer.tulas Common Issues with a System Unit System Unit will not turn on Before proceeding to perform advanced troubleshooting, it is advisable to check for these basic checks first: Check the power cable/AVR/UPS/ extension cord to make sure it is plugged in and turned on. Check for any loose cables on the motherboard Check the outlet for power problems. Try plugging the cord to a different outlet. Try a different power cable. If the system unit still refuses to turn on, we may proceed to perform these advanced troubleshooting techniques. There are available power supply testers available on the market. In the absence of such a tool, you can proceed to perform the paper clip test on the PSU. - Unplug every cable from the PSU from where they are connected. - Obtain a paper clip. Bend the paper clip to resemble a “U” shape. - If the paper clip is coated, use a blade or knife to strip and expose the bare metal on both ends of the paper clip. - Insert one end of the paper clip to the lone green pin and the other to the gray pin. - Turn the PSU on. If the PSU fan starts to spin, the PSU is ok and is functioning normally. - In the case of other PSUs where their cables are not color coded and all black, you may refer to the diagram below. - Insert the paper clip on pins 8 and 16. One other thing to check for is the power button the front panel. Short the power switch pins on the motherboard Trace the cable/wires coming from the power switch to the motherboard. Disconnect the wires from the motherboard, making note of the location of the power and ground connectors. Jump or short the two pins for the power and ground directly on the motherboard with a metallic instrument (screwdriver) momentarily. If the last step works, the problem is a loose connection between the power switch and the motherboard. System unit powers on but screen is entirely black Double check if RAM is installed properly. Unplug the RAM sticks (one by one if there multiple) to find the faulty RAM stick Clean the RAM slots and the contact points of the RAM stick with a clean piece of cloth. Reseat the RAM sticks. System unit will not boot the OS Troubleshooting a system unit that will not boot the OS requires a basic understanding or the overview of the boot process. To boot is to load the OS. An overview of the boot process is as follows: - The unit loads the BIOS - The BIOS performs the POST - The BIOS loads the MBR to the RAM - The BIOS loads the boot loader/ boot manager/ boot strapper - The boot loader loads the OS Power-on Self-test (POST) The computer POST (power-on self-test) checks a computer's internal hardware for compatibility and connection before starting the remainder of the boot process. If the computer passes the POST, the computer may give a single beep (some computers may beep twice) as it starts and continues to boot. However, if the computer fails the POST, the computer may generate a beep code telling the user the source of the problem. The most common causes of POST failures are problems with the following components: BIOS ROM RAM CPU Video card Motherboard *Note: Except for Dell and Mac, your computer or motherboard manufacturer is not the BIOS manufacturer. Determine the BIOS manufacturer for your computer's motherboard, then search for a reference for beep code meanings. American Megatrends Inc. (AMI) beep codes 1 Short Beep A single short beep from an AMI-based BIOS means there has been a memory refresh timer error. You'll need to start by replacing the memory (RAM). If replacing the RAM doesn't work, you should try replacing the motherboard. 2 Short Beeps Two short beeps mean there has been a parity error in base memory. This problem affects the first 64 KB block of memory in your RAM. Like all RAM problems, this isn't something you'll be able to fix yourself or get repaired. Replacing the RAM modules that cause the problem is almost always the fix. 3 Short Beeps Three short beeps mean there has been a base memory read/write test error in the first 64 KB block of memory. Reseating or replacing the RAM usually solves this AMI beep code. 4 Short Beeps Four short beeps mean that the motherboard timer is not working properly but it could also mean that there's a problem with the RAM module that's in the lowest (usually marked 0) slot. Usually, a hardware failure with an expansion card or a problem with the motherboard itself could trigger this beep code. Start by reseating the desktop memory module and then replacing it if that doesn't work. Next, assuming those ideas have failed, reseat any expansion cards and then replace any that seem to be the culprit. Replace the motherboard as the last option. 5 Short Beeps Five short beeps mean there has been a processor error. A damaged expansion card, the CPU, or the motherboard could be prompting this AMI beep code. Start by reseating the CPU. If that doesn't work, try reseating any expansion cards. Chances are, however, the CPU needs replaced. 6 Short Beeps Six short beeps mean that there has been an 8042 Gate A20 test error. This beep code is usually caused by an expansion card that has failed or a motherboard that is no longer working. You might also be dealing with a certain kind of keyboard glitch if you hear 6 short beeps. When troubleshooting A20 errors, you may need to reseat or replace any expansion cards. Lastly, you might be dealing with a failure severe enough that you'll need to replace your motherboard. 7 Short Beeps Seven short beeps indicate a general exception error. This AMI beep code could be caused by an expansion card problem, a motherboard hardware issue, or a damaged CPU. Replacing whatever faulty hardware is causing the problem is usually the fix for this beep code. 8 Short Beeps Eight short beeps mean that there has been an error with the display memory. This beep code is usually caused by a faulty video card. Replacing the video card usually clears this up but verify it's sitting properly in its expansion slot before buying a replacement. Sometimes this AMI beep code arises from just a loose card. 9 Short Beeps Nine short beeps mean that there has been an AMIBIOS ROM checksum error. Literally, this would indicate an issue with the BIOS chip on the motherboard. However, since replacing a BIOS chip is sometimes impossible, this AMI BIOS issue is usually corrected by replacing the motherboard. Before you go that far, try clearing CMOS first. If you're lucky, that'll take care of the problem for free. 10 Short Beeps Ten short beeps mean that there has been a CMOS shutdown register read/write error. This beep code is usually caused by a hardware failure with the AMI BIOS chip. A motherboard replacement will usually solve this problem, although it could be caused by a damaged expansion card in rare situations. Before you go replacing things, start by clearing CMOS and reseating all the expansion cards. 11 Short Beeps Eleven short beeps means that the cache memory test has failed. Some piece of essential failing hardware is usually to blame for this AMI BIOS beep code. Often times it's the motherboard. 1 Long Beep + 2 Short Beeps One long beep and two short beeps is usually an indication of a failure within the memory that's part of the video card. Replacing the video card is almost always the route to go here, but try removing and reinstalling it first, just in case the only problem is that it has wiggled a bit loose. 1 Long Beep + 3 Short Beeps If you hear one long beep followed by three short ones, this is due to a failure above the 64 KB mark in the computer's system memory. There's little practicality in this test versus some of the earlier tests because the solution is the same—replace the RAM. 1 Long Beep + 8 Short Beeps One long beep followed by eight short beeps means that the video adapter test has failed. Try reseating the video card and making sure any auxiliary power it needs is connected to the power supply. If that doesn't work, you'll need to replace the video card. Alternating Siren Finally, if you hear an alternating siren-type noise at any time during your computer use, at boot, or afterward, you are dealing with either a voltage level problem or a processor fan that's running too low. This is a clear indication that you should turn off your computer and inspect both the CPU fan and, if possible, the CPU voltage settings in BIOS/UEFI.  ------ END ------ Prepared by: Naycer Jeremy G. Tulas [email protected] 09129412101 https://www.facebook.com/naycer.tulas