I have a 2017 iMac Pro running Ventura. I have attached two different 4k LG monitors, one at a time, and both exhibit the same behavior. They intermittently go black for a second or two, then come back on. They do this every few minutes. They are attached to a lightning port via an HDMI dongle. I have swapped out the HDMI cable and the power cable for the monitors. Both monitors work without a problem on a Dell computer. Any ideas?
iMac Pro, macOS 13.0
What USB-C to HDMI adapter do you have?
About the Apple USB-C Digital AV Multiport Adapter - Apple Support
Belkin USB-C to HDMI Adapter -Apple
Some after market USB-C to HDMI adapters will work and some will not.
For more info, see > Connect an external display to your iMac - Apple Support
What USB-C to HDMI adapter do you have?
About the Apple USB-C Digital AV Multiport Adapter - Apple Support
Belkin USB-C to HDMI Adapter -Apple
Some after market USB-C to HDMI adapters will work and some will not.
For more info, see > Connect an external display to your iMac - Apple Support
Thanks for the response den.thed. I have a Warrky adapter that claims that it is compatible with the iMac Pro and a 4K monitor at 60 Hz. Trying out a different adapter would probably be the next least expensive troubleshooting step available though.
You’re welcome.
In addition to testing one of the Apple recommended adapter(s) or another third party adapter. You will also want to use the shortest possible Premium Certified HDMI cable instead of the LG supplied and other cheap-o HDMI cables.
external monitor intermittently black
