Title: Troubleshooting a Non-Booting PC: No Signal, No POST, and Blinking Motherboard LED
Introduction
Encountering a PC that refuses to boot can be frustrating, especially when no clear error messages or beeps provide guidance. If your system, configured with an AMD Ryzen 5 3500X and ASUS Prime B450M-A II motherboard, suddenly ceases to start properly—showing no signal, no Power-On Self Test (POST), and a blinking LED indicator—it’s essential to conduct a systematic troubleshooting process. This article aims to guide you through common causes, troubleshooting steps, and considerations to diagnose and potentially resolve such issues efficiently.
System Overview
- Processor: AMD Ryzen 5 3500X
- Motherboard: ASUS Prime B450M-A II
- Memory: 16GB DDR4-3200 (two sticks, tested individually)
- Graphics Card: NVIDIA GeForce RTX 3070 8GB
- Storage: 1TB NVMe M.2 SSD
- Power Supply: Be Quiet System Power B9 600W
- Usage History: Stable operation for over five years with no recent hardware changes
Symptoms Description
Recently, the system abruptly ceased to boot. When powering on:
- The CPU fan spins slowly and continuously.
- The GPU fans spin briefly then stop.
- The motherboard’s LED pulses slowly in an orange color, resembling standby mode.
- No display output.
- No POST beeps or BIOS activity.
- The system appears to power up but remains in a limbo state.
Initial Troubleshooting Steps Taken
The following steps have been attempted to diagnose the issue:
- Memory Checks: Swapped RAM modules; tested each stick individually across different slots.
- Graphics Verification: Removed and reseated the GPU; checked power connections.
- CMOS Reset: Removed the motherboard’s CMOS battery and waited several minutes; also bridged the Clear CMOS pins with a screwdriver for approximately 10 seconds.
- Peripheral and Cable Testing: Verified monitor and cable functionality with other devices.
- Visual Inspection: Ensured all fans and LEDs are powered; no visible damage or burns.
Key Questions for Diagnosis
Given that the basic troubleshooting hasn’t resolved the issue, consider the following questions:
- Motherboard Power State: Could the motherboard be dead despite receiving standby power? Is the blinking LED an indicator of a specific fault?
- Power Supply Functionality:
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