Monitor going black regularly The monitor connected to my Mac mini is going dark regularly for a few seconds, then he comes back up. What could this be? It is not a flickering, the monitor just loses connection.


Mac mini (Late 2012)
macOS High Sierra 10.13.6
Monitor is a Dell U2713HM
second monitor which blacks out only very rarely (but he does as well sometimes.)


I have checked the cables about 100x times.
The most common causes for these types of blackouts are poor cables, poorly shielded monitors or excessive environmental noise.

If you have nearby sources of EMI (electromagnetic interference), try moving these sources or the monitor/computer/cable. In practice I have seen for example 4G/LTE hot spots, burglar alarms, stereo receivers and other similar equipment cause blackouts.

The next step is to replace the cables with properly shielded cables of a good quality.

If that doesn't help, contact your the seller of the monitor for support.