Question

Difficulty: EasyMotherboard, RAM, CPU, and Power Issues

A technician is troubleshooting a desktop computer that turns off immediately after being turned on. What is the correct sequence of steps the technician should follow to diagnose and resolve a suspected power supply issue according to standard troubleshooting procedures?

  1. 1Verify that the external power cable is securely connected to a known-working wall outlet and the power supply rocker switch is turned on.
  2. 2Check that internal motherboard power connectors, including the 24-pin ATX and 8-pin EPS power cables, are firmly seated.
  3. 3Measure the power supply voltage outputs using a dedicated PSU tester or multimeter.
  4. 4Replace the defective power supply unit with a functional, known-good replacement unit.

Answer

The correct sequence begins with verifying external power, checking internal motherboard cable seating, testing PSU rail voltages with a dedicated tester, and finally replacing the faulty power supply unit.
CompTIA troubleshooting methodology requires prioritizing simple external verifications before inspecting internal connections, taking tool-based measurements, and performing component replacement.

Step-by-Step Solution

1
Verify external power sources and connections.
Ensures utility power is actively reaching the power supply inlet.
Standard troubleshooting dictates starting with simple external checks first.
2
Inspect internal power cable seating on the motherboard.
Confirms 24-pin ATX and 8-pin EPS connectors are fully latched.
Loose motherboard power leads can cause thermal trip or immediate power-off events.
3
Test power supply outputs using a multimeter or PSU tester.
Identifies if voltage rails (+12V, +5V, +3.3V) are within proper operating specs.
Direct measurement isolates PSU electrical failure before performing component swaps.
4
Swap out the bad PSU for a functional replacement unit.
Restores consistent power to all system hardware components.
Remediation via hardware replacement occurs after empirical failure verification.

Key Concept

Power Supply Diagnostics and Isolation Sequence
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