The following is the General Troubleshooting Theory that is used by Mac engineers to troubleshoot Mac hardware computer problems.
Below is the accurate flowchart:
Gather Information -> Verify Issue -> Try Quick Fixes -> Run Diagnostics -> Systematic Fault Isolation -> Research ->Repair -> Verify Repair ->Inform User
In the book, Desktop and Portable Systems, there is a detailed account of the necessary troubleshooting steps.
Below, I will review the most important information in regards to troubleshooting your computer.
Verify the issue, including the steps that will re-create the issue. This might be possible, but sometimes it is not. It all depends on the nature of the fault. For example, if the motherboard does not start, then there is nothing to re-create.
Try Quick Fixes. I personally never do quick fixes as almost all faults that I have seen in my practice were such that quick fixes could not help, and sometimes quick fixes just made the problem worse.
Run Diagnostics. This is actually my favorite step. If the system is doing something that it is not supposed to do, it is advised to run stress tests until the issue reveals itself. There are many tools that are used for diagnostics and stress tests.
Systematic Fault Isolation. The popular method for troubleshooting includes starting by eliminating roughly half of the items you are checking for instead of trying to re-create the issue. Continue halving your search group until you find the source of the issue. But, I believe that in order to troubleshoot quickly and easily, the best route to take is disconnecting everything and starting with a minimal system to boot it from using a diagnostic CD.
Research; use all available information resources to identify the fault.
Repair all the procedures and steps that are necessary to replace the faulty part or reinstall the system with a data back up. Data back up must be a part of the troubleshooting process. I personally have never lost data, but I know that it does happen. Customers sometimes forget to ask for data backup or do not realize that all the data is located on the hard drive and not on the USB stick with shortcuts.
Verify Repair. ASD AHT for Apple and everything that is mentioned below for PC are used as stress test tools.
Inform The User. Sometimes, customers might call to check on the repair. And, the best method is to let them know how the repair is going or even inform them that it is complete.
Here is my method: I call this method the hybrid hardware troubleshooting method because I rely on the knowledge of common faults. At the same time, I use system stress tests as well as diagnostic/measurement tools. I do this by disconnecting everything from the motherboard on the desktop, or I disconnect all peripherals that are connected to the laptop. Test the hard drive – usually the most frequently failing part. For a quick diagnostic, use GSmartControl or HDTune (which will take longer). If everything looks okay, then test the memory or, in other words, the RAM. If the memory is okay, then scan for viruses. If the system does not show any sign of fault, then stress test it with OCCT for a couple of hours. Check the power supply if it is a desktop and the power adaptor if it is a laptop. The oscillogram of all power lines should be straight with no fluctuations whatsoever. If it shows spikes or moves up and down, then it is better to replace the power supply or the power adaptor. I would suggest checking the motherboard visually for anything that looks suspicious. For example, capacitors with damaged tops or overheating elements as well as ICs like South Bridge. The capacitors on the top must lay flat and the components on the motherboard can be warm or even hot, but not extremely hot. If it feels impossible to hold a finger on an element such as the South Bridge, then something is wrong with it or something is wrong with another component in the same circuit. Capacitors usually stay room temperature. MOSFETS are usually warm, and sometimes hot, but not extremely hot. The CPU can be on heavy load hot, but you should still be able to keep a hand on it without burning. Actually, a lot of diagnostic work can be done just by checking the temperature. Sometimes, because design engineers make a mistake, the Integrated Circuits don’t get enough cooling. This is a very common problem on laptops with dedicated graphics cards, as well as desktops with passive cooling systems such as South Bridges and North Bridges.
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