LG UltraFine 5K - Owners Thread

[Quotenfrau]

Anyone noticing the colour on the LG is a bit strange since upgrading to OSX 26 ?

I haven't noticed anything negative after the macOS 26 upgrade.

 

[rb24]

I haven't noticed anything negative after the macOS 26 upgrade.

Thanks for getting back. I've now tried with another laptop - running an older OS - and the colour cast remains. Searching the net it seems that some kind of LG motherboard failure can produce this result. Must have coincidentally happened at the same time (as OSX26). May have to go in for service. Annoying this happens when there's rumour that an upgraded Apple Studio is imminent.

 

[ralphthemagi]

Thanks for getting back. I've now tried with another laptop - running an older OS - and the colour cast remains. Searching the net it seems that some kind of LG motherboard failure can produce this result. Must have coincidentally happened at the same time (as OSX26). May have to go in for service. Annoying this happens when there's rumour that an upgraded Apple Studio is imminent.

Try unplugging the Mac entirely (both the Thunderbolt and mains cables). Leave it off for 15 minutes or until the display is completely cold. Plug the Mac back into the mains and ensure that the power supply you’re using can provide the maximum wattage the machine accepts (e.g., don’t use a 30W power supply on a 60W device—you want to make sure no USB-PD connection is established with the display). Turn on the display using AC power. Wait for 30 seconds. Plug the Thunderbolt cable into the display first, and then the Mac. Repeat this process five times. If you get the same result every time, the logic board on the display is likely faulty. If the color cast disappears, the device fails to connect, or you notice any strange intermittent issues (e.g., USB or audio connection established but no display) during one of those five connection attempts, it’s most likely that the pads or traces around the Thunderbolt port have degraded. This degradation causes strange intermittent issues due to thermal expansion and contraction.

I own numerous of these displays, and the troubleshooting process is consistently frustrating. The only solution is to persistently attempt various combinations of plugging and unplugging. If the results remain consistent, the issue lies with the logic board. Conversely, if the results are intermittent, it’s almost always the pads on the connector itself. At least this has been my maddening experience with these displays.

 

[Genelec8341]

I wish I could find a second one for sale locally at a decent price. Mine is still going strong since new in 2021, though I have never connected anything to the inbuilt USB-C ports. After reading about the thermal issue here, I never will!

 

[ralphthemagi]

I wish I could find a second one for sale locally at a decent price. Mine is still going strong since new in 2021, though I have never connected anything to the inbuilt USB-C ports. After reading about the thermal issue here, I never will!

The USB-C ports are safe to use and likely will not fail. The issue is the single Thunderbolt port—that is the one that fails.

 

[Genelec8341]

The USB-C ports are safe to use and likely will not fail. The issue is the single Thunderbolt port—that is the one

Thanks. I should have been more specific regarding your caution using PD. I use a CalDigit for all of my USB-C data and PD needs.

 

[rb24]

Try unplugging the Mac entirely (both the Thunderbolt and mains cables). Leave it off for 15 minutes or until the display is completely cold. Plug the Mac back into the mains and ensure that the power supply you’re using can provide the maximum wattage the machine accepts (e.g., don’t use a 30W power supply on a 60W device—you want to make sure no USB-PD connection is established with the display). Turn on the display using AC power. Wait for 30 seconds. Plug the Thunderbolt cable into the display first, and then the Mac. Repeat this process five times. If you get the same result every time, the logic board on the display is likely faulty. If the color cast disappears, the device fails to connect, or you notice any strange intermittent issues (e.g., USB or audio connection established but no display) during one of those five connection attempts, it’s most likely that the pads or traces around the Thunderbolt port have degraded. This degradation causes strange intermittent issues due to thermal expansion and contraction.

I own numerous of these displays, and the troubleshooting process is consistently frustrating. The only solution is to persistently attempt various combinations of plugging and unplugging. If the results remain consistent, the issue lies with the logic board. Conversely, if the results are intermittent, it’s almost always the pads on the connector itself. At least this has been my maddening experience with these displays.

Thanks for this. Tried the lengthy voodoo like sequence of manoevres 3X (not 5)... I guess it's a logic board fault.

FWIW don't ever plug/unplug the cable from the monitor so my connector has a good chance of being in reasonable shape.

 

[iNICK20]

I bought an 27MD5K for $300 + $100 shipping. It arrived the next day, and it ended up being a 27MD5KA model. I was a little disappointed but I guess what can you expect? I was hoping for a newer model with less issues and the iPad Pro support like my other one. But the owner who bought it, said it works great and he upgraded to a dual Studio Display.

 

[EugW]

The USB-C ports are safe to use and likely will not fail. The issue is the single Thunderbolt port—that is the one that fails.

Anecdotally at least, is this issue ONLY with Thunderbolt Power Delivery to laptops? What about with Mac minis, Mac Studios, and Mac Pros?

I just ordered the LG UltraFine 6K 31.5" model, and haven't decided yet if I'm using Thunderbolt or HDMI. My M4 Mac mini has HDMI 2.1 so I have both options available to me. I'm leaning toward HDMI 2.1 though since it'd be nice to free up a Thunderbolt port, the M4 Mac mini doesn't support Thunderbolt 5, and I don't have any Thunderbolt 5 devices anyway.

 

[vbctv]

Anecdotally at least, is this issue ONLY with Thunderbolt Power Delivery to laptops? What about with Mac minis, Mac Studios, and Mac Pros?

I just ordered the LG UltraFine 6K 31.5" model, and haven't decided yet if I'm using Thunderbolt or HDMI. My M4 Mac mini has HDMI 2.1 so I have both options available to me. I'm leaning toward HDMI 2.1 though since it'd be nice to free up a Thunderbolt port, the M4 Mac mini doesn't support Thunderbolt 5, and I don't have any Thunderbolt 5 devices anyway.

I have never had an issue with my M2 Pro Mac mini before or my M4 Pro Mac mini now.... The thunderbolt area does NOT feel warm at all. Probably because the Mac mini like the other Mac desktops are display only and have their own external Power. While the MacBooks do both display and power thru the Thunderbolt port.

 

[ralphthemagi]

Anecdotally at least, is this issue ONLY with Thunderbolt Power Delivery to laptops? What about with Mac minis, Mac Studios, and Mac Pros?

I just ordered the LG UltraFine 6K 31.5" model, and haven't decided yet if I'm using Thunderbolt or HDMI. My M4 Mac mini has HDMI 2.1 so I have both options available to me. I'm leaning toward HDMI 2.1 though since it'd be nice to free up a Thunderbolt port, the M4 Mac mini doesn't support Thunderbolt 5, and I don't have any Thunderbolt 5 devices anyway.

Primarly yes, but the display can fail even without PD. It's just very poorly designed.

No one knows about the new model. Hopefully they have fixed the issues with the old design… it's certainly been long enough.