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LG 31MU97 4k Display

Looking to connect the 2016 MBP to this monitor (TB3 to Displayport). I was able to find a USB-C to regular Displayport cable on Amazon (LINK).

Anyone know where I can get a male to male USB-C/TB3 to Mini Displayport cable?

Just to be clear, I don't want to use a USB-C dongle to connect Mini Displayport. I just find Mini Displayports easier to disconnect than regular Displayport.
 
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I've bought an LG 31MU97 too. After I've got the first model, I noticed overheating issues and very impressive backlight bleeding. So, I decided to ask a replacement, but also the new one was a bad unit. Both were, sometimes, flickering when connected to my MacBook Pro 2015 and they were produced during August 2016.

Here is the images of both LG 31MU97 during black screen test. Have you tried to do a similar test to yours?
Schermata 2017-02-07 alle 18.42.39.jpg


Schermata 2017-02-07 alle 18.42.46.jpg
 
So am I right that the new 6,1 new Mac Pro cylinder can run this 31MU97-B display now at true 4K at 60hz? Or is it still stuck at 50hz?
 
am_macrumors said:
With my MacBook Pro 2015, I was able to run the 31MU97 at true 4K 60Hz. I think the new Mac Pro can run it at the same resolution & refresh rate.

More info here: https://support.apple.com/en-us/HT206587
Click to expand...


Thanks for the reply. I saw that on Apple support pages, I was just worried because when I looked into it a few years ago the display would only run at 50hz.

Further, LG's own webpage still says it will only run at 50hz.
 
The thunderbolt version will only support thunderbolt @ 50Hz (LG limitation)
MiniDP to DP is fine at 60Hz.
I run 2 of these on a Mid2015 MBPr using the 2 thunderbolt ports on the Mac.
Daisy chaining is not supported.

I have discovered the flickering was caused by OSX setting a refresh rate not supported by the display.
In the back of the manual it gives supported resolutions @ refresh rates and the cable connections that are compatible at those settings. By using SwitchResX I have set various hot key combinations for resolutions I like to work at for various tasks. Once I keep the refresh rates within spec for the cable type connections I am using, I have had no issues with either display.

Before I found this out, I was plagued with random blackouts and flickering ... but all gone now for the past 2 months.
Everything is stable at...
MiniDP-DP 4096x2160 @ 60Hz
Thunderbolt 4096x2160 @ 50Hz
Thunderbolt and any HiDPI scaled setting.

Hope this helps anyone setting up these excellent monitors, I love mine.
 
I just received my MacBook Pro 15 (late 2016) and my LG 31MU97z-b but I can do anything, but max. resolution with thunderbolt via T3 to T2 adapter is 3840x2160. Same when I press alt+scaled.....PRAm rested...any ideas? Any drivers or special setup Mac/LG necessary?

Regards, Sascha
[doublepost=1487514681][/doublepost]sorry, meant PRAM reseted.
 
smy said:
I just received my MacBook Pro 15 (late 2016) and my LG 31MU97z-b but I can do anything, but max. resolution with thunderbolt via T3 to T2 adapter is 3840x2160. Same when I press alt+scaled.....PRAm rested...any ideas? Any drivers or special setup Mac/LG necessary?

Regards, Sascha
[doublepost=1487514681][/doublepost]sorry, meant PRAM reseted.
Click to expand...

Try Apps like QuickRes or SwitchResX to get access to many more resolution options.
 
turbineseaplane said:
Try Apps like QuickRes or SwitchResX to get access to many more resolution options.
Click to expand...
Thanks a lot - no improvemts thereafter....but I wondered, when I saw, that they offered me always 30 Hz..

I finally found it: besides the monitor I connected my Raid and my Lan access via T2...with Monitor last in the chain....I changed the sequence to monitor first and....it works!
 
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Does anyone with this monitor hear a sporadic crack/creaking sound from this monitor? This is with the sound muted.

Thanks.
 
beccas said:
Does anyone with this monitor hear a sporadic crack/creaking sound from this monitor? This is with the sound muted.

Thanks.
Click to expand...

How often? Like a "pop" or can you describe it more?

Could be a logic board dying - That happened to mine - Took $300 LG repair to get it fixed.
:-(
 
turbineseaplane said:
How often? Like a "pop" or can you describe it more?

Could be a logic board dying - That happened to mine - Took $300 LG repair to get it fixed.
:-(
Click to expand...

I really can't describe it. Maybe a pop? I am not sure. It happens randomly and it sounds like it comes from different places on the back (not concentrated to one area). If it is a sign of fault, that would suck. I just got it and it is refurbished so my warranty window is smaller.

How soon after you heard the sound did you had to send it in for repair? Are you still hearing the sounds? What revision is your monitor?
 
beccas said:
Does anyone with this monitor hear a sporadic crack/creaking sound from this monitor? This is with the sound muted.

Thanks.
Click to expand...

Hi,
I had the same issue and I tested it for weeks. I can say now it is all about the cable you use.
Try with a different cable. For me best working is MiniDP to DP cable which was delivered with the display..
Had this cracking sound (every minute) also with USB-C to DisplayPort Adapter Cable from StarTech and with MiniDP to MiniDP.
HDMI is working fine but only with 24Hz.
Regards
 
beccas said:
I really can't describe it. Maybe a pop? I am not sure. It happens randomly and it sounds like it comes from different places on the back (not concentrated to one area). If it is a sign of fault, that would suck. I just got it and it is refurbished so my warranty window is smaller.

How soon after you heard the sound did you had to send it in for repair? Are you still hearing the sounds? What revision is your monitor?
Click to expand...

I hear the same sounds. None when I first had the monitor, then two months later, some severe popping and screen blanks. Then nothing for a year or more. Now I occasionally get pops, usually after running the system without rebooting for 5 days or more.
 
Tom9999 said:
Hi,
I had the same issue and I tested it for weeks. I can say now it is all about the cable you use.
Try with a different cable. For me best working is MiniDP to DP cable which was delivered with the display..
Had this cracking sound (every minute) also with USB-C to DisplayPort Adapter Cable from StarTech and with MiniDP to MiniDP.
HDMI is working fine but only with 24Hz.
Regards
Click to expand...

I only use the supplied cable. It's good to hear that I am not the only who is experiencing this. The monitor is not even active when the sound is heard sometimes.


toomanyipods said:
I hear the same sounds. None when I first had the monitor, then two months later, some severe popping and screen blanks. Then nothing for a year or more. Now I occasionally get pops, usually after running the system without rebooting for 5 days or more.
Click to expand...
I don't get screen blanks...at least for now. Have you heard of any more users of this monitor experiencing this?

Thanks guys!
 
Watch out guys. I'm positive the popping will lead to circuit board failure that I had to have fixed.

Absolutely no popping ever since the new board has been in. Faster at input switching as well.
 
I'm looking for some help on this. I purchased a LG 31MU97-B for my nMP and I can not get it to work at all in a way I think it should. I can only get 4096x2160 @ 50hz. Any other resolution will display nothing. So no scaled resolutions. If I choose any of those I will get just a blank display. If I plug the monitor into my 2014 retina iMac everything is beautiful, all scaling modes with 60Hz no problem at all so I know my cable is ok. But on my nMP I can only do one resolution at 50hz. How are others getting scaling and 60hz working on there 2013 nMP? I am running 10.12.4 I thought all of these issues were sorted out.
 
Has anyone been able to get a 31mu97-b working with a USB-C/TB3 based Mac? In particular a 2017 5k iMac?

The monitor has worked fine with my Windows gaming rig and my TB2 based Macs. With a 2017 iMac I've tried more than a few TB3 and USB-C to Displayport adapters that specifically claim they support 4096x2160@60Hz such as:

http://www.cablematters.com/pc-831-...ayport-adapter-for-mac-windows-computers.aspx

and

http://www.kanex.com/usb-c-dp-adapter
(click the Technical Specifications at the bottom)

It freezes the iMac screen on and off when connected and never comes up as a display. I have been using the same cables I used with my TB2 based Macs or my Windows rig but have also tried other cables.
 
Signal64 said:
Has anyone been able to get a 31mu97-b working with a USB-C/TB3 based Mac? In particular a 2017 5k iMac?

The monitor has worked fine with my Windows gaming rig and my TB2 based Macs. With a 2017 iMac I've tried more than a few TB3 and USB-C to Displayport adapters that specifically claim they support 4096x2160@60Hz such as:

http://www.cablematters.com/pc-831-...ayport-adapter-for-mac-windows-computers.aspx

and

http://www.kanex.com/usb-c-dp-adapter
(click the Technical Specifications at the bottom)

It freezes the iMac screen on and off when connected and never comes up as a display. I have been using the same cables I used with my TB2 based Macs or my Windows rig but have also tried other cables.
Click to expand...

I haven't been able to get it to work with 4 different adapters and both a 2016 13" MacBook Pro and a 2017 MacBook Pro 15". Works flawlessly with my 2015 15" MacBook Pro of course (TB2)

Super frustrating
 
On the iMac the only errors I can find is in /var/log/displaypolicy/displaypolicyd.PEG0.log
Note: On Macbooks "PEG0" might be POP0 or something else.

https://pastebin.com/raw/NjEXEYpe

Every "inject FB[2] change" the iMac monitor freezes up and repeats until the monitor is unplugged. I thought it might be due to the Standby mode the monitor is in and the timing of becoming active. I switched the monitor to standby after 4hrs (simulating always on) and that just increased the duration of freezing on the iMac screen.

I compared it to my Late 2013 rMBP and TB2 display port connection and the first 4 lines are the same and the monitor displays correctly.

So now I'm back to having to try and contact LG, Apple, and the maker of the devices. All of which can point fingers at each other. I may just get a new monitor but still looking at options. I don't want another LG.
 
BTW, if you switch the monitor to Displayport 1.1 it does "work" but at the gimped 3840x2160@24Hz resolution. In the log you can see it negotiate at the slower HBR speed just fine.

I've opened a bug report with Apple and contacted LG and Cable Matters.

Response from LG:

1. Is there a firmware update for the 31MU97-B? I'm being asked as there appears to be a timing issue negotiating the DisplayPort configuration of 4-lanes SST @ HBR2 speed when using a USB-C or Thunderbolt 3 adapter.

A. Checking with our support system or even in the LG website there is no firmware release for the LG monitor model 31MU97-B

2. Is there an LG recommended Thunderbolt 3 or USB-C adapter to use with the LG 31MU97-B?

A. We from LG do not recommend adapters. First this is because LG did not manufacture and not guaranteed to work. All LG monitors are plug and play device means no special device driver is required. Your system, upon Power On and boot up after installing and connecting the new monitor to the computer it will recognize and load native software drivers automatically using recommended cable only (not using adapters docking station or converters).

Second, adapters are usually being recommended by the computer or graphics card original equipment manufacturer.
 
Last edited:
Got the 31MU97 4K display to run at 60hz at full res from my 2017 iMac (4GB VRAM)! I got the Moshi USB-C to displayPort cord (5k one at 1.5m or 5ft)
image.jpg
image.jpg
 
I have bought this monitor for 300€
It works like a dream for colour, but only via tb2 at 3840x2160 on a Mac mini 2014
On the 2016 rmbp I would like to try the adapter, but red that this will not work
Any other suggestion on cable settings for both devices?
 
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