1.2.3 Establish and Test a Theory - Quick Notes

Goal: use symptoms to identify the probable cause, then devise tests to confirm or rule it out. Be methodical so you do not skip possibilities, and be efficient so you solve it quickly.

Conduct Research

• Perform a physical inspection. Look and listen for clues such as a scorched board or unusual fan noise.
• Reproduce the problem if the symptoms are not visible. Intermittent issues are the hardest to troubleshoot.
• Check system documentation, event logs, and diagnostic tools.
• Ask other techs. Someone else may have worked on the system, or another team may have made infrastructure changes without notice.
• Check vendor documentation, web searches, and forums for known fixes.

Key Reminder

Do not rely only on the user's description. Research independently to clarify the symptoms and probable causes.