Monitor Dell U2412M - MacBook Pro (2019) - recognizes, but with no image

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Monitor Dell U2412M - MacBook Pro (2019) - recognizes, but with no image

I have a MacBook Pro 2019 and I am trying to connect the Dell U2412M monitor with the (official )USB-C Digital AV Multiport Adapter, through an HDMI-DVI-D cable. DVI-D on the monitor (it has no HDMI) and HDMI on the adapter.

The monitor is identified correctly by the notebook, appears in "about this... monitors" - but no image ever appears on the screen of the monitor. I messed around with all kinds of configurations and had no success. Any ideas how to get this done? Would another cable, other than the HDMI-DVI-D be necessary?

And by the way, the monitor and the cables work fine as they are. If I plug it in the HDMI of a PC it appears instantly with no problem. Also, I have more than one adapter and tested both on all 4 ports - with the same results throughout.

Thanks,

Wagner

Posted on Sep 1, 2021 12:25 PM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

133,411 points

Sep 1, 2021 6:01 PM in response to wagner_mn_santos

Maybe it doesn't like two adapters.

how about one adapter direct from the USB-C port to DisplayPort:

Monoprice Bidirectional USB Type-C to DisplayPort Cable - 4K@60Hz, Black, 6ft - Product # 39240 - $18.89

.

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Answer 2

Sep 1, 2021 1:53 PM in response to wagner_mn_santos

If you have [√} Mirror Displays set, the built-in display and the external display will BOTH be set to use a "compromise" resolution. Sometimes this resolution does not work for one display, the other, or both.

This is what Mirror Displays looks like:

In addition to the checkbox, the two blue Icons representing screen area are nearly-overlapped.

.

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Answer 3

Sep 1, 2021 12:54 PM in response to wagner_mn_santos

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. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• 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.

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Answer 4

Sep 1, 2021 1:41 PM in response to Grant Bennet-Alder

Hey Grant, thank you for your response. :)

Unfortunately, guess I l already tried a combination of all of those. I did put the macbook to sleep, turned it off, restarted, etc - same with the monitor - trying all permutations.

And about the monitor, I tend to believe that it is "ready" (listening to the proper input), because this happens:

1 - it is working, plugged to a PC through the HDMI

2 - I plug it in on another PC, it works fine again, no intervention needed. I can repeat 1 and 2 and it is always ok.

3 - If I plug it in the macbook (through the adapter) the screen "blinks", same happens with the screen on the macbook, as both appear to be exchanging information - the OS recognizes the monitor, all configurations show up as they should, but nothing ever appears on the external monitor. And as I said, at this stage I tried putting it to sleep, wake up, restart, detect monitors, everything.

I am thinking it might be because the macbook is sending something the monitor cannot process/render, because at this stage not even the monitor controls/displays appear on screen, only if I unplug it.

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Answer 5

Sep 1, 2021 1:02 PM in response to wagner_mn_santos

1920 by 1200

DisplayPort and DVI inputs.

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Answer 6

Sep 1, 2021 2:02 PM in response to Grant Bennet-Alder

Yeah, I tried with it checked and unchecked - and all those permutations that I mentioned. Numerous times... :(

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Answer 7

Sep 2, 2021 1:17 PM in response to Grant Bennet-Alder

Yeah! I had just ordered this exact cable as you posted this tip here. It arrived and has worked. You're a trooper and an invaluable asset to the community Grant. Thanks!! :)

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Monitor Dell U2412M - MacBook Pro (2019) - recognizes, but with no image

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