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rurza

macrumors member
Original poster
Feb 27, 2011
51
31
Hey,
I've recently noticed that my 4K Ultrafine stopped, yeah, stopped working (Mac is charging, but there is no picture on the external display itself) when connected to the right side of the 2018 13" Macbook Pro. Resetting SMC (there are two ways to reset it on the Macbooks with T2) and PRAM didn't helped. Running fresh OS from external hd didn't resolve it either. Updating to the newest beta didn't helped. :/
The display has the newest firmware.


Any ideas?
 
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Painter2002

macrumors 65816
May 9, 2017
1,197
943
Austin, TX
Have you tried a different cable? It is possible that when you plug it in on the one side it is bending the cord in a certain way that has damaged the internals of the cable and thus limiting the functionality of the cord. I would try a new cable before I do anything else.

Also, you specify the right side of the laptop is where the plug is plugged into, does the monitor work correctly if plugged into one of the left side ports?
 

rurza

macrumors member
Original poster
Feb 27, 2011
51
31
Have you tried a different cable? It is possible that when you plug it in on the one side it is bending the cord in a certain way that has damaged the internals of the cable and thus limiting the functionality of the cord. I would try a new cable before I do anything else.
I've tried different positions and bending to opt-out the cable. It always charging. And...

Also, you specify the right side of the laptop is where the plug is plugged into, does the monitor work correctly if plugged into one of the left side ports?

It works when connected to the left side. On both ports.
 

Painter2002

macrumors 65816
May 9, 2017
1,197
943
Austin, TX
I've tried different positions and bending to opt-out the cable. It always charging. And...

It works when connected to the left side. On both ports.
I know it may not be cheap, but it may be worth trying an entirely new cable still. Otherwise your next best bet is to reach out to Apple and see if there is an issue with the USB-C ports on the right side of your machine not utilizing the full bandwidth of power/data.

I am going to lean on the side that it may still be the cable, as even when you bend it and try to reposition that it may or may not fix the issue.

The only other suggestion is to possibly unplug the LG monitor from power (at the surge protector or wall plug), and see if that resets the monitor and Mac connection. I have had that issue before on one of my monitors that was plugged into my Mac via a Caldigit dock, and unplugging the monitor at the power source fixed the issue.
 

rurza

macrumors member
Original poster
Feb 27, 2011
51
31
The only other suggestion is to possibly unplug the LG monitor from power (at the surge protector or wall plug), and see if that resets the monitor and Mac connection. I have had that issue before on one of my monitors that was plugged into my Mac via a Caldigit dock, and unplugging the monitor at the power source fixed the issue.

It didn't helped :(

I know it may not be cheap, but it may be worth trying an entirely new cable still. Otherwise your next best bet is to reach out to Apple and see if there is an issue with the USB-C ports on the right side of your machine not utilizing the full bandwidth of power/data.

I am going to lean on the side that it may still be the cable, as even when you bend it and try to reposition that it may or may not fix the issue.

I've ordered a new cable (hopefully good, with 10Gbps transfer and PD) :)
Hopefully it'll help :) Thank you for your time :)
 
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rurza

macrumors member
Original poster
Feb 27, 2011
51
31
Few updates on this topic:
External disk doesn't work on the right side either. I feel that it's spinning, but the OS doesn't recognize it and the white LED doesn't turn on. Again – everything is fine on the left side. But, if the disk is connected to the computer before the OS asks for FileVault password everything is fine (I see the LED light). So I thought that maybe it was software related after all.

So I've downgraded the Mac OS to High Sierra but without any success :(

Edit 2: It looks like the ports on the right side can't provide enough bandwith to push the 4K display. Sometimes the external HD is recognized by the OS (few minutes after connecting it) and the System Information displays 480Mb bandwidth :/
 
Last edited:

Painter2002

macrumors 65816
May 9, 2017
1,197
943
Austin, TX
Few updates on this topic:
External disk doesn't work on the right side either. I feel that it's spinning, but the OS doesn't recognize it and the white LED doesn't turn on. Again – everything is fine on the left side. But, if the disk is connected to the computer before the OS asks for FileVault password everything is fine (I see the LED light). So I thought that maybe it was software related after all.

So I've downgraded the Mac OS to High Sierra but without any success :(

Edit 2: It looks like the ports on the right side can't provide enough bandwith to push the 4K display. Sometimes the external HD is recognized by the OS (few minutes after connecting it) and the System Information displays 480Mb bandwidth :/
You stated this is a 2018 MBP, which would mean you have a one year hardware warranty still active. Given this, I’d definitely take it in to Apple, and have them check it out. If you are having issues with any devices plugged into the right ports, it well could be the i/o ports are fried on that side, especially if you’ve tried downgrading software and the ports on the other side work fine.

Beyond doing that, I think you’ve covered all the possible software solutions (except the new cable), so this sounds more like a hardware issue.
 
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