Identify issues with the PC startup process following shutdown.
Identify issues with the PC startup process following shutdown.
A short while ago I purchased a refurbished ASRock Phantom Gaming 4 Z590 for my i7 11700K. Once I replaced the memory module, the computer started on its own after I connected it. The following day I attempted to power it up but it wouldn’t respond. I switched the PSU on and off, and it rebooted itself again. I adjusted the power settings via Control Panel and reinstalled drivers, yet the issue remained unresolved. I inspected every connection inside the case and confirmed they were intact. The power button functions for shutting down but fails to start the system. Additionally, the power indicator on the case turns off briefly after a shutdown and comes back on within seconds. Compared to my previous setup using an MSI H510M PRO-E board, everything operated smoothly. The power button itself isn’t the issue since the problem continues even when it’s disconnected, and attempting to short the pins didn’t resolve it. My complete system specs are: i7 11700K, ASRock Z590 Phantom Gaming 4, Kingston HyperX Fury 2x8GB at 2400MHz DDR4, ASRock RX 6700 XT, Challenger Pro 12GB cooler, Cooler Master MWE Gold V2, 750W full modular 2TB HDD, and a 500GB Samsung Evo 2.5" SSD.
It might be a hibernation or sleep mode configuration you have active. If the LED turns off when you power off the PC and then lights up again after shutdown, it suggests your BIOS is handling hibernation. Check the advanced power settings under Windows for related options like suspend to RAM or C-states. Ensure Fastboot is turned off in your BIOS settings. Another possibility is a power supply issue—some PSUs have power factor correction problems. The fact that the motherboard powers on by itself when connected isn’t always harmful, but it could mean a loose button was pressed or a ground connection was broken, causing a boot attempt.
It seems the issue originated from the second monitor linked via a DP→HDMI cable. After disconnecting it, the power indicator stopped working but the computer started up fine. I don’t understand why this happened.
After reviewing the information, it appears the issue lies with the DP→HDMI cable you're using. Certain cables can allow power to flow backward into the motherboard via the GPU, causing shutdown problems. This problem is common and often referred to as the "DP pin 20 issue." It seems a simple fix might involve adding a diode to block reverse current, but since you're new to electronics, the solution could be more involved.
I haven't come across this before and have been using a 4K DP monitor for nearly two years without any issues. Of course, now that I've mentioned it... It seems the connection method for the dp-hdmi dongle varies depending on the model. That's going to be a bit tricky every time you purchase one.