USB_C ports

[richmond62]

Suddenly my 3rd monitor stopped working, and all the ports on the USB-VGA converter went 'wonk' . . . thought it was the converter. Anyway, after a lot of pissing about it turns out that the port marked in green on the back of the Mac Mini seems to be 'dead', and I am able to get the 3 video signals out of the ports marked in orange (which the official Apple documentation says is not possible) . . .

 

[DeepIn2U]

But you’ve highlighted only 3 of the 4 TB3 ports and with the HDMI cable.
Have you done a hardware diagnostic or just have the problematic USB-C port connected to your adapter and this external screen?

 

[joevt]

What official Apple documentation?

As far as I know, you can connect two displays to any one (using a Thunderbolt dock or adapter or device) or two Thunderbolt 3 ports, and a third display to the HDMI port.

 

[richmond62]

No, I have done no hardware diagnostic as I do not know how to I am: I am an EFL teacher and educational programmer, not a whizz with machines.

Of course, if you want to be a "nice person" you could let me know how to do a diagnostic.

 

[Erehy Dobon]

All four Thunderbolt 3 ports function the same and have identical capabilities. All four will drive video.

If that one port does not drive video anymore, you need to get the machine serviced. Assuming you are in a location where the Apple Stores are closed due to COVID-19, I suggest you contact Apple Support (online, phone) and have them start a repair ticket now. When the stores reopen, you can take it in.

If you haven't already done so, you should try different cables in the suspect port. Cables can go bad too.

 

[Tygernoot]

I have the exact same issue! The first port appears to have died right after I installed the latest security updates just now!

** Edit **
This worked for me: https://forums.macrumors.com/threads/lost-thunderbolt-port-with-10-15-4-beta-6.2227374/

 

[Fishrrman]

Well... looking at Apple's "reset" for SMC on t2 Minis... I guess mine gets "reset" every night.
I keep my Mini plugged into a power strip, and shut down the Mini and POWER OFF the power strip every night...

 

[djc6]

Well... looking at Apple's "reset" for SMC on t2 Minis... I guess mine gets "reset" every night.
I keep my Mini plugged into a power strip, and shut down the Mini and POWER OFF the power strip every night...

That doesn't reset SMC

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

1. Shut down your Mac.
2. Press and hold the power button for 10 seconds, then release the button.
3. Wait a few seconds, then press the power button to turn on your Mac.

You only perform step 1 every night

 

[DeltaMac]

That doesn't reset SMC

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

1. Shut down your Mac.
2. Press and hold the power button for 10 seconds, then release the button.
3. Wait a few seconds, then press the power button to turn on your Mac.

You only perform step 1 every night

Fishrrman mentioned having a T2 mini, which (reading that same article for relevant info) says to unplug the power cord, which is essentially what happens when you turn off the power strip that the mini is using for power.
(from that same Apple support article):

Desktop computers with the T2 chip

1. Shut down your Mac, then unplug the power cord.
2. Wait 15 seconds, then plug the power cord back in.
3. Wait 5 seconds, then press the power button to turn on your Mac.