Linux+: Hardware Part 18 – Technical Troubleshooting Computer systems can and do fail. When a system fails to start or perform properly there are steps that can be used to determine the failure and repair it. Eight basic repair steps are as follows: Determine symptoms Find the specific area affected Distinguish what has been changed Make out a list of probable causes Plan out a solution Implement a solution and test result Check effects and side effects of solution Note problem and solution 1. Determine the symptoms This step is a matter of determining what problem is occurring. A mouse cursor isn’t moving or a hard drive is not accessible. Make out a list of all symptoms you can find. This is important since the list will be needed later to determine that the problem and all its symptoms are fixed. 2. Find the specific area affected Sometimes this step may be a very easy one, but occasionally it can be difficult. For instance, you sit down at the computer and move the mouse but the cursor remains in place on the screen. Your initial reaction may be that the mouse is broken or unplugged. You check and find that the mouse is connected to the Universal Serial Bus (USB). Next, you may want to use the keyboard to maneuver around the system, but find that it doesn’t work either. After checking, you find it too is plugged into the USB port. Not as simple of a problem as you first thought. When determining the area affected don’t check one item, check others which are similar. In the previous case with the mouse and keyboard it could easily be that a USB controller has failed to initialize, or failed completely when the system started. If you have a USB network adapter which is not letting you connect to a network, you can determine a few things. Can others connect? – this can narrow down if it is a network problem or if it is only your system If it is my system, could it be my whole USB system? – Check other USB devices to see if they work properly If it is my system, is it my network card? 3. Distinguish what has been changed Sometimes this step can cause more harm to your investigation of the problem. Say for instance you have the previous mouse problem. You think about it and remember that the software driver was updated. If the problem is the USB controller, then you will be going after the wrong solution. With the symptoms list also make a list of what has changed since the previous time you booted the system or made changes. NOTE: Sometimes it can be beneficial to reboot the system and try again. It is not uncommon for a reboot to fix problems by re-initializing drivers and resetting the Random Access Memory (RAM). 4. Make out a list of probable causes Once you have the symptoms and possible areas you can list out the possible causes. This is really an extension of finding the area affected. You can be broad in scope here at first and narrow down the scope on your list. As a precious example of a USB network adapter which is not allowing you to connect, but others can, you could compose a list as follows: USB controller Network Adapter Network Adapter driver Network settings 5. Plan out a solution Now, you make a list of what you are going to do to determine the problem. With the previous example you can specify the following: Check other USB devices to determine if the problem is the USB controller. If other devices work you could switch a working device with the network adapter. Move the network adapter to the working devices port and the working device to the network adapter’s original port. If there is no change then the problem is not the USB controller. If the problem is fixed but the other USB device now does not work then you could have multiple USB controllers and one has failed. Now, you can start troubleshooting the failed USB controller. It may be possible that the USB port itself has malfunctioned and is unusable. Checking the Network Adapter can be a simple one and may be performed first. If your adapter has failed you can easily tell by swapping with someone else that has an identical adapter which is working. If your adapter works in their system the problem is not the adapter. The problem can be the USB controller, the adapter or settings. Drivers can sometimes cause problems. It is possible for drivers to be updated and all settings lost. If the network adapter driver was updated it is possible that all the network settings were lost. It may also be possible that the driver has flaws which do not allow the adapter to work properly. If possible, rollback to the previous driver which did work. For a network adapter to connect to the network there are multiple settings which must be correct for a connection to be made. Check the settings, or at an extreme reset the settings to default and rest them. It is possible that the settings could be in conflict with another network user causing your adapter to not initialize properly. 6. Implement a solution and test result Determine which solution you try first. It is usually best to try simple solutions first before the harder ones. NOTE: Basically, try all solutions first that do not require a system to be opened. It is possible to cause a lot of damage to internal components of an open system for Electro-Static Discharge (ESD). ESD is the same static that you feel when you are shocked by a doorknob or other metal object. The static can ‘fry’ components in a system and you may not even feel the discharge. Once you implement a solution test to determine if the problem and symptoms have been fixed. Examples were given in the previous section along with the possible solutions. It is sometimes best to make out a plan of attack with each solution as I did. By adding this to the list it can help your mental processes by thinking the solution through and determining if you are leaving out any possible issues such as the USB controller. Even if the USB controller works the problem could be the individual port. 7. Check effects and side effects of solution Once you perform a possible solution it is best to make sure everything works as needed. For example, if the problem was a USB mouse and the mouse is working it is best to check all other USB devices to verify that another device was not unplugged or caused to fail in some manner. Whatever system was fixed, check other devices, if any exist. Another example is if a SCSI device failed and the problem was resolved check the other SCSI devices. 8. Note problem and solution It can be beneficial to keep a notebook of any changes made to a system. For example, any time an application is installed or updated a note can be made with time and date. If a problem pops up afterward the notebook can be consulted and you know what was previously changed. When a problem is fixed you can make a notation of the problem and solution. If the problem occurs again you can find your solution and repair the problem easily. If you notice that problem keeps occurring it can be determined that your solution was not a long term fix. At this point, it is best to try another solution and hope the problem stops permanently. NOTE: For any assistance with technical issues it is sometimes easiest to search for the problem on the Internet using Google or Bing.