ATEM Mini blanks out every hour or so

I have an ATEM mini which is switching HDMI video at 1080p/60 from a number of PCs and a Mac to a Philips HDMI monitor.

The input from the Mac Mini (via Thunderbolt->HDMI Adapter) blanks out every hour or so.
When it blanks out the Mac does not know. The only way to recover is to reboot the Atem or unplug/replug the HDMI Input. The monitor thinks it is getting a valid, but blank, signal.

I have spent a lot of time trying to get to the bottom of this, and have concluded it's probably an issue with the ATEM Mini because of the following:

1. Plugging the HDMI Adapater directly into the monitor = no issues.
2. Using another brand of good quality HDMI Siwtcher = no issues.
3. Using the cheapest 4-in, 2-out HDMI Switcher from Amazon = no issues.
4. Moving the Mac input to a different port on the Atem = same issue on all ports.

I have tried altering the framerate and the same thing happens on each setting.

So I think there is maybe something in the Atem firmware or hardware which doesn't quite like the input from this HDMI Adpater? After some time it just blanks the signal only a physical act will re-sync it.

My ATEM is running f/w version 8.6

*EDIT Spelling and Grammar *

I'd start by checking the sleep/power settings on the Mac.

Then check the HDMI cable. How long is it? How good is it? Anything over 3m with 60P is taking a chance with any ATEM.

I'd start by checking the sleep/power settings on the Mac.

Then check the HDMI cable. How long is it? How good is it? Anything over 3m with 60P is taking a chance with any ATEM.

Thanks for the reply.
Yeah...it's a good quality HDMI cable, 1.5m long, and none of the other switchers I use have this issue.
It's not the sleep settings on the Mac, this monitor is the 2nd monitor on the mac which I use in a 2-monitor setup. Just the one going via the ATEM blanks out - and nothing brings it back on short of re-initialising the ATEM input.

No worries - if no one else is seeing this, it must be something unique to my setup.
Is there any form of diagnostics mode for the ATEM where I can watch an event log or anything like that?

Is your ATEM getting really hot?
Amazon has coolers you can put it on for cheap.

I never did get to the bottom of this. In the end I just removed the iMac from the ATEM and put it on the 2nd HDMI input of the monitor.

However I'm now seeing the same behaviour with DP over USB-C adapters from a different iMac to a different ATEM. So different adapter, different ATEM, different iMAc, same issue.

It also shows if I remove thr ATEM and replace it with a pair of BMD Microconvertors. So it's DP/USB-C/HDMI to SDI Microconvertor then along an SDI cable to HDMI Microconvertor to monitor. Same issue.