LG Ultrafine with different issues depending on CPU

[josiahla]

Hi!

I just got my hands on a used LG Ultrafine 27" 5K (Version A). It has some issues with my work MacBook (Intel) and different issues with my personal MacBook (M1 Pro).

On Intel: Display connects, charges MacBook and lights up, but suddenly turns off the panel every +- 10 seconds, stays black for 1-2 seconds and turns on again. Charging, speakers and webcam continue working.
On M1 Pro: MacBook asks for me to allow the connection of a Thunderbolt accessory (monitor), the popup disappears and shows up again after a few seconds. This doesn't stop until I allow/reject it. Although the MacBook charges, the monitor doesn't light up.

I read that Version A has some shielding issues and can disconnect when placed too close to a WAP for example. I tried the monitor in multiple places around the house, still same issues.

I also tried multiple Thunderbolt cables:
- LG TB3 cable that came with the monitor
- Apple TB3 cable
- Caldigit TB3 cable
-> Same results with every cable.

Does anyone know what this could be caused by? Faulty Thunderbolt port on the monitor? I know this is a common issue for Ultrafine monitors.

Thanks in advance,
Josiah

 

[transmaster]

Watching this thread I need a new monitor for my Mac Studio,

 

[IsaacFOK]

Is the monitor new? Also try swapping the TB cable ends.

 

[josiahla]

Is the monitor new? Also try swapping the TB cable ends.

Nope, it's used. I tried swapping cable ends yesterday, no luck sadly. Weirdly enough, the monitor worked fine with the Intel MacBook all day, still no luck with the M1 MacBook tho.