4.1. Troubleshooting Core Components

💡 First Principle: To diagnose systemic failures, you must use a logical process of elimination based on observable evidence (e.g., POST codes, error messages, physical signs) to isolate the issue to a core component.

Scenario: A user reports their desktop PC will not turn on at all. There are no lights, no sounds, and no fans spinning. Your diagnostic path starts outside the case: check the wall outlet with a known-good device, check the power cable is seated firmly, and check the PSU's power switch. Only then do you proceed to test internal components.

When a computer fails to boot or behaves erratically, the problem often lies with one of the core components. Troubleshooting these issues requires careful observation and a methodical approach.

⚠️ Common Pitfall: Immediately assuming the most expensive component (like the motherboard or CPU) has failed. The problem is often much simpler, like a loose cable or a faulty power supply.

Key Trade-Offs:

• Component Swapping vs. Diagnostic Tools: Using a PSU tester is a quick, non-invasive way to check a power supply. Swapping it with a known-good unit is more definitive but also more time-consuming.

Reflection Question: When a PC fails to boot, why is checking the power source (from the wall outlet to the PSU) the most logical first step before opening the case?