I’m having some strange issues with my Mac Mini 2018 running a Samsung Ls34j550 monitor via DisplayPort. ( I also have a second different monitor running via HDMI behaving as expected.)
When the Mac Mini sleeps the Samsung display goes into a loop of no signal, saying it will go into stand by mode in 3 seconds, turning off then back on and repeating. Strangely when this happens an external hard spins up before shutting down and a USB powered device also powers on then off. Eventually the screen turns completely off and won’t turn back on unless the power is unplugged and re plugged. During this cycle the 2nd monitor remains in stand by.
This issue has returned. The monitor goes into sleep in the evening but in the morning the LED is not flashing and the screen is blank and won't power on until unplugging the power supply.
I have bought this monitor, it is attached to my PC via HDMI and is one of 2 monitors. Every now and then, while I am using the computer the monitor powers off, going blank for a few seconds, then comes back on. I have swapped the power cable and have also changed the plug socket. I have also changed the HDMI lead. Any ideas? Thanks for your time.