sarcademy/syllabus/troubleshooting/troubleshooting.md

Troubleshooting Hardware

RAM

1. Symptoms: Frequent crashes, Blue Screen of Death (Windows), or kernel panics (macOS/Linux).
2. Steps:
   • Turn off the computer and unplug it.
   • Open the case and reseat the RAM modules.
   • Try booting with one RAM stick at a time to isolate faulty modules.
   • Use software like MemTest86 to test RAM.

CPU

1. Symptoms: Overheating, system instability, or failure to boot.
2. Steps:
   • Check the CPU temperature using BIOS or software like HWMonitor.
   • Ensure the CPU fan is working and reapply thermal paste if needed.
   • Check for bent pins or damaged components.

Motherboard (MB)

1. Symptoms: Failure to boot, no power, or irregular behavior.
2. Steps:
   • Inspect for physical damage like burnt areas or bent pins.
   • Check all connections and reseat components.
   • Test with minimal hardware to isolate issues.

Power Supply Unit (PSU)

1. Symptoms: No power, random shutdowns, or system instability.
2. Steps:
   • Use a PSU tester or multimeter to check voltage levels.
   • Inspect for physical damage or burnt smell.
   • Replace if faulty.

Troubleshooting Network

OSI Model

Use the OSI model as a framework for troubleshooting network issues. Start from the bottom layer and work your way up.

1. Physical Layer: Check cables, switches, and other hardware.
2. Data Link Layer: Verify MAC addresses and ensure devices can communicate within the same local network.
3. Network Layer: Check IP addresses, subnet masks, and routers.
4. Transport Layer: Verify that TCP or UDP ports are open and listening.
5. Session Layer: Ensure that sessions can be established and maintained.
6. Presentation Layer: Check for data format or encryption issues.
7. Application Layer: Verify that the application is functioning as expected, check for updates or patches.