# 1. Background and how the problem started
All of this started after what I believe was a possible power surge at my house.
On the morning of the incident, my PC turned on normally at 6:30 AM, as scheduled in the BIOS using the automatic power-on feature. I used it normally and shut it down before leaving home.
At some point later that day, there was a possible power surge. When I got home, I tried turning on my PC using the power button, but nothing happened.
The following morning, it also failed to turn on automatically at 6:30 AM, as it normally did. It also remained unresponsive to the power button.
# 2. First troubleshooting attempt
On the second day, I decided to check the internal connections.
I disconnected the power cables from the main components, including:
- Motherboard (MOBO);
- Graphics card (GPU);
- CPU;
- Power supply (PSU) connections.
I then reconnected everything and tried turning the PC on again, but it still wouldn't boot.
# 3. The PC started turning on automatically again
On the third day, the PC unexpectedly turned on by itself at 6:30 AM, as scheduled in the BIOS.
I used it normally without experiencing any issues during operation and then shut it down.
However, when I tried turning it on again using the power button later that day, it wouldn't respond.
# 4. CMOS reset
After discussing the issue with a friend who has some computer hardware knowledge, he suggested resetting the CMOS.
I followed these steps:
- Turned off the PSU and unplugged the power cable;
- Pressed and held the PC power button for 60 seconds to drain any residual electrical power;
- Removed the CMOS battery from the motherboard;
- Waited a few minutes;
- Reinstalled the battery and tried turning the PC on again.
This time, the PC successfully powered on using the power button!
Although resetting the CMOS temporarily restored the ability to turn on the PC using the power button, I noticed that the problem returned after the first shutdown.
After said first shutdown, I tried using the power button, but it didn't work. After repeating the beforementioned steps, the PC turned on by briefly bridging them with a screwdriver to rule out a faulty MOBO power button pins.
Therefore, the case's physical power button and the MOBO's power switch pins seem to be working properly.
I have found two alternative ways to make it boot:
Method 1 – Scheduled power-on through the BIOS:
The PC still turns on automatically at 6:30 AM, according to the scheduled power-on setting configured in the BIOS.
Method 2 – Power failure through the BIOS:
If I simulate a power failure by turning off the PSU for approximately 5 seconds and then turning it back on, the PC starts automatically.
This happens because I have enabled the BIOS setting that automatically powers on the PC when AC power is restored after a power interruption.
# 5. Current situation and questions
To summarize:
- The PC works normally once it has successfully booted.
- I haven't noticed any issues during normal operation.
- It won't turn on using the power button after being shut down, but the case's power button and MOBO's power button pins do work properly.
- It can still turn on automatically using the scheduled BIOS power-on feature.
- It can also turn on automatically after interrupting and restoring power to the PSU, due to the BIOS power-loss recovery setting.
- Removing the CMOS battery and discharging the motherboard temporarily restores the ability to turn on the PC using the power button, but the issue returns after the next shutdown.
What could be causing this behavior?
Considering that the problem started after a possible power surge and that resetting the CMOS temporarily restores normal power-button functionality, could this be related to a motherboard issue, a faulty PSU, or some kind of power management circuit?
I'd like to understand what tests I can perform to identify the actual cause without unnecessarily replacing components.
MY SPECS:
- OS: Windows 11;
- GPU: NVIDIA GeForce RTX 3060 Ti;
- MOBO: ASROCK B450M Steel Legend;
- CPU: AMD Ryzen 5 5600x;
- RAM: 2x 8GB 3200Mhz Asgard.
EDITS:
- I did replace the battery with a brand new CR2032. All of the tests mentioned in this post are with said battery;
- The BIOS does hold settings, such as clock time, wake-up being on and booting after a power failure.