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Second monitor not working with Mac Pro (Mid 2010)

I am attempting to hookup a second monitor to my Mac Pro. It is running High Sierra 10.13.6. I purchased a Monoprice Mini DisplayPort to DVI Cable and hooked it up to an older monitor that supports 1680 x 1050 resolution. I can't get a signal to it, and when I open up System Preferences > Displays, nothing shows up. I reset PRAM also, and still no luck. What else can I do to fix this? Thanks.

Mac Pro, macOS 10.13

Posted on Aug 10, 2020 10:49 PM

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Question marked as Top-ranking reply

Posted on Aug 11, 2020 6:49 AM

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

 

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

 

so try doing some of those things and see if the display comes alive.


Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.


Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.


Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.

10 replies
Question marked as Top-ranking reply

Aug 11, 2020 6:49 AM in response to Pritch

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

 

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

 

so try doing some of those things and see if the display comes alive.


Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.


Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.


Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.

Aug 11, 2020 5:21 PM in response to Grant Bennet-Alder

Thanks for your reply. I have tried all of those options, and it still won't work. For some reason it just won't recognize that the second display is hooked up. The detect display button didn't do anything either. I'm really surprised that this doesn't work. I bought the Displaylink to DVI adapter, and I thought I could just plug it in and the Mac would recognize it. Is there anything else I can do?

Aug 11, 2020 5:29 PM in response to Pritch

Yes, if using DisplyLink hardware, you need to load the DisplayLink software. DisplayLink provide a display "faked" in software.


For less money, you can get a real, Hardware accelerated display using the hardware built into your Mac.


If this is the 42lb silver tower, what graphics card is installed?

If not what Model MacBook Pro by year, early mid late, screen size and processor speed??

Aug 12, 2020 4:35 PM in response to Pritch

'Mini DisplayPort to Dual-Link DVI adapter' requires that you supply POWER on the USB pigtail. You can plug that short USB cord into a "real" USB port, or you can use any other 5 Volt power source like an iPad charger.


That certainly sounds like cracking nuts with a B-52 bomber, unless that adapter "fell on you". The Apple ones sold for US$100 when new.

Aug 12, 2020 4:36 PM in response to Grant Bennet-Alder

Well, you won't believe this (but you probably will), but just for grins, for like the 6th time, I pulled out the displaylink cable from the mac, and reconnected it, but this time I shoved it in there really hard, and now it works. I feel like an idiot, but I had it in there pretty **** good the first 4-5 times I tried. I thought I might have broken it when I shoved it in real hard that last time. I'm recovering from back surgery, and my right hand has been very weak lately because of it for some reason. And that was the hand I was using. But I still had it in there good those other times. Guess you really have to cram it in there. Anyway, it works. Thanks so much for your time. Much appreciated.

Second monitor not working with Mac Pro (Mid 2010)

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