here is my setup:
My mac mini 2018:
16 gb ram
1 to ssd
intel graphic 630 uhd 1536 mo
I am using two external displays.
One TV full hd bravia Sony from 2011
One projector Epson Tw-1000 full hd.
Both were used with old macbook pro without issue for almost 10 years with another graphic card intel HD vintage.
When i am plugging only one display, either on hdmi cable direct or via apple adaptater usb c - HDMI , i have no issues at all with display.
When i am plugging my two external display, sometimes i am losing signal with a black screen with my projector only.
The HDMi signal (for the projector) is going to the Yamaha RXV467 receiver before going to the projector Epson.
I am not using both display in the same time. Either the projector, either the full hd tv.
Cables are fine, i tried many. (1.4, 2.0, not cheap,...)
Adapter or hdmi direct, nothing changed.
Reset smc, nothing changed.
Safe mode, nothing changed.
Reset pram, nothing changed.
Install again mojave 10.14.2, nothing changed.
Format the hard drive and install clean mojave only. Nothing changed.
Most part of the time ih happend When watching videos, whatever the video software i am using. (vlc, kodi,...)
i tried everything that apple care and apple told me to do. For me, there is a problem with hdmi management when using multiple display, depending or the display.
I tried not using at all the Yamaha receiver (just for the test), it's working great, i am losing signal on the projector anymore. however, the receiver works great when it's plugged on the mac mini without the full hd television sony plugged as well.
This graphic car can handle at least 3 external display in 4k....now i am trying only with two in 1080p.
Also i tried a HDMI switch A/B connected to the hdmi port of the mac mini. the problem is still there.
I tried also a hdmi splitter to the hdmi port of the mac mini, the problem disappeared but it's not a solution for me for two reasons: splitter means duplicate and the sound of my receiver is not the same that the tv (dolby digital,dts,...) and also this graphic card should be able to manage multiple display on his own with the hdmi port and the 4 USB-C port on the rear of the machin.
i am losing signal randomly, after 15 minutes, 40 minutes, hours... for 1 or 2 seconds.
but more i am using the mac without restarting or sleeping, and the problem disappear. The problem is coming back after shutting down, restart, or wake up after sleeping.
All these are non sense, that's why i need expertise from intel.
second problem: sometimes it’s not possible to wake up the mac after long sleep. Not with the mouse, trackpad, keyboard or rear button.
i had to power up the mac manually.
I tried to touch some features in the settings but it didnt change anything.
nothing special Written in the console by the way for both problems.
If anybody can help or give me some news? i am already in discussion with apple for all these topics, but i think it's coming from the graphic card driver or something.
i spent at least 300 hours on these problems. myself alone, with apple on the phone, with apple store genius bar. nothing is working. so i am trying with you... maybe i ll get lucky.
maybe it's coming from the osx version or the driver of the graphic card.
I don't know. i just know that there are a lot of people with similar problem with multiple display on the web.
thanks a lot.