Computer keeps cutting power- and computer repairman can’t find a single issue

Understanding Unexplained Computer Power Losses: Troubleshooting Tips When Hardware Seems Fine

Experiencing sudden computer shutdowns can be incredibly frustrating, especially when the cause isn’t immediately clear. Recently, a user reported their PC randomly powering off without warning—completely cutting power while other devices on the same extension cord remained unaffected. Despite thorough diagnostics, the issue persisted without an obvious source. In this article, we’ll explore potential reasons for such power interruptions and practical steps to diagnose and resolve them, even when hardware tests come back clean.

Case Summary

The user described their computer shutting down unexpectedly without any Windows shutdown message—simply, the power cut off. Other electronic devices connected to the same outlet continued functioning normally, suggesting the problem wasn’t solely with the power strip or outlet. The user had to manually turn off the PC using its power switch and wait before restarting.

A professional computer repair technician conducted comprehensive diagnostics, including memory, storage (SSD), GPU, and CPU stress tests. Remarkably, the hardware tests revealed no issues, and the technician was unable to reproduce the problem under controlled conditions. This situation leaves several questions: Could the cause be a faulty power cable? An unstable wall socket? Or possibly something else?

Potential Causes and Troubleshooting Strategies

Power Cable and Delivery Stability
- Cable Condition: Even if the PC’s power cable appears intact, it may be internally damaged or of poor quality, leading to intermittent power delivery. Consider testing with a different, high-quality power cable known to function correctly.
- Connection Check: Ensure the cable is securely connected both to the power supply unit (PSU) and the wall outlet. Loose connections can cause sudden power losses.
Wall Outlet and Circuit Stability
- Outlet Inspection: Test the wall socket with another device to confirm it supplies consistent power. If other devices also experience power issues, the problem might reside with the outlet or wiring.
- Circuit Load and Stability: Heavy load on the circuit, such as other high-power appliances, can cause voltage drops that lead to PC shutdowns. You might consider testing from a different, dedicated outlet or consulting an electrician.
Power Supply Unit (PSU) Reliability
- PSU Faults: Even if hardware diagnostics pass, the PSU itself could be failing or intermittently failing under certain loads. PSU issues can cause sudden shutdowns without warning.
- Testing or Replacing: Consider