MacPro monitor setup with LG 34" problem.

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Level 1

9 points

MacPro monitor setup with LG 34" problem.

I bought a Macpro and decided to use a 34" LG monitor which is ultra wide and has a thunderbolt port. I couldn't get the monitor to work depite connecting via the thunderbolts. I tried connecting via the HDMI ports too but the screen doesn't boot. I can change settings of the monitor and it looks like it's ok. the LG monitor was advertised as MacPro ready so I bought it rather than the very expensive 4K monitors. I'd appreciate any help or suggestions. Thanks.

Posted on Sep 30, 2014 11:32 PM

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Answer 1

lllaass

Level 10

210,411 points

Oct 1, 2014 1:08 AM in response to vman1027

Monitor's/TV do not have Thunderbolt ports. Some have displayports and mini displayports. The Thunderbolt port supports video out via a mini display port.

Just how di yo connect the monitor to the Mac Pro?

Did yo select the right input on the monitor?

It should work fine with a mini displayport connection to the monitor.

Note that although a Thunderbolt cable end looks like a mini displayport cable end they are not interchangeable. Yo need to use a mini displayport/display port cable for video

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Answer 2

vman1027 Author

Level 1

9 points

Oct 1, 2014 6:50 AM in response to lllaass

The LG 34UM95 has thunderbolt input so that's how I connected it to the Mac Pro, thunderbolt to thunderbolt. when I turn on the Mac the screen is just blank. I could make adjustments on the monitor settings thru the monitor itself So I know the monitor must be ok. I tried connecting using HDMI instead of thunderbolt but the same thing happens. I could hear the MacPro running though cause it's asking me my preferred language but the monitor screen is blank. Do you think I need another connection? The monitor has 2 thunderbolt inputs in the back.

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Answer 3

lllaass

Level 10

210,411 points

Oct 1, 2014 9:06 AM in response to vman1027

Your monitor does have both Thunderbolt ports and a displayport in addition to an HDMI port.

Per the manual (page 16) is is not clear what the Thunderbolt port is really for except it mention dual monitors

You can download the manual here:

http://www.lg.com/us/support-product/lg-34UM95-P#

What cable are you using? To use the Thunderbolt port you need a Thunderbolt cable which is different than a mini displayport cable eventhough they will both plug into either a mini displayport or Thunderbolt port.

What I would do would be to get a displayport to mini displayport cable (about $10) and use that for the video.

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Answer 4

vman1027 Author

Level 1

9 points

Oct 1, 2014 1:01 PM in response to lllaass

I Use thunderbolt cable I bought with Macpro. I dunno why it's not working. I'll try what you recommended but what a waste of thunderbolt cable if I can't use it for the monitor.

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Answer 5

lllaass

Level 10

210,411 points

Oct 1, 2014 1:09 PM in response to vman1027

I have no idea. Yours is the first post I have seen with using Thunderbolt monitor except for Apple's Thunderbolt monitor

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Answer 6

vman1027 Author

Level 1

9 points

Oct 1, 2014 1:19 PM in response to lllaass

No worries. Was gonna get the thunderbolt monitor then I found this 34" LG and I thought it would be better than having 2 monitors.

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Answer 7

Nov 1, 2014 11:32 AM in response to vman1027

Hi vman1027:

did you solve the MacBook Pro to LG 34" monitor connection problem? I have the same problem

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Answer 8

Nov 2, 2014 6:22 AM in response to vman1027

I have the Macpro & 34UM95 screen

I figured it out, to connect the Thunderbolt cable (and make it drive the screen) one must use the on/off toggle switch at the bottom of the screen to pick the LG's (on screen) menu and then pick the Thunderbolt connection option to connect the screen.

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Answer 9

Nov 2, 2014 6:24 AM in response to vman1027

I have the Macpro & 34UM95 screen

I figured it out, to connect the Thunderbolt cable (and make it drive the screen) one must use the on/off toggle switch at the bottom of the screen to pick the LG's (on screen) menu and then pick the Thunderbolt connection option to connect the screen.

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Answer 10

vman1027 Author

Level 1

9 points

Nov 2, 2014 6:53 AM in response to RoySutton

Sorry got this message just now. Glad it worked out for you. Mine was a little complicated. I had to set up the MacPro using my TV then connected the LG via thunderbolt to the MAcPro and it worked. Then I disconnected the TV from the MacPro and the LG became the main screen. It was all good after that.

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Answer 11

manuelhe

Level 1

8 points

Nov 25, 2014 10:23 AM in response to RoySutton

My resolution was to use an HDMI to DVI cable. HDMI output from MacBook, DVI input on the LG monitor.

I have an LG 27 inch monitor that would not work with my MacBook Pro (2013) when I connected via HDMI output to HDMI input on the monitor or by using a thunderbold adapter to HDMI input on the monitor.

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Answer 12

Feb 28, 2015 12:45 PM in response to vman1027

I had an issue connecting the monitor to 2 different MacBook Pros using an Apple Thunderbolt cable. The monitor never show in the list of Thunderbolt devices on my MacBook Pro. However the monitor worked fine when I switched to another Thunderbolt cable I had (OWC brand). After some further testing, I found I simply had a bad Thunderbolt cable.

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Answer 13

Feb 10, 2016 4:01 AM in response to vman1027

I had the same problem. LG 34" worked great with my Mac Mini but was black when I bought a late 15 iMac 27". Called LG and they told me that monitor won't work on a 2015 iMac so I reluctantly put the monitor on eBay. Before it sold I thought I'd contact Mac support and the genius senior advisor I spoke with walked me through a few steps and cleared out some old junk files and settings and then presto....LG 34" worked. Glad I didn't sell it!

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Answer 14

Feb 27, 2016 12:10 PM in response to macdaddy360

Can you share specifically what files he removeed/deleted?

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Answer 15

Feb 27, 2016 12:18 PM in response to ngerasimatos

I wish I knew I would have written the steps down and shared for you but I did a screen share and he walked me through several steps in areas the I am def. not familiar with. I have sent that tech an email asking him to share here so hope he does.

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