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flyman

macrumors regular
Original poster
Jan 28, 2004
114
0
Hi Everyone,

Today I've just taken delivery of a lovely new Mac Mini which I've connected to my albeit rather old Benq FP241W monitor via HDMI.
Unfortunately the picture quality is pretty awful with it being distorted and pixelated but I'm not sure why?
I've checked system prefs and there's no adjustment there I can make so can anyone suggest what might be wrong?
For reference I also have my Mac Pro 3.1 connected via DVI-D and I just change input on the monitor to with between devices - This works absolutely fine!

Thanks in advance
 
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Fishrrman

macrumors Penryn
Feb 20, 2009
28,483
12,614
Try a different connection method.
USBc (Mini end) to HDMI (display)
or
USBc (Mini end) to DVI (display).
 

flyman

macrumors regular
Original poster
Jan 28, 2004
114
0
Last night I tried another HDMI to HDMI and it was still same.
Today I tried a usb c to HDMI but this time all I got was a blue screen!
Would there be any settings somewhere I need to change or is it possible my monitor isn't incompatible?
 

flyman

macrumors regular
Original poster
Jan 28, 2004
114
0
To further update when I look at about this Mac/displays/ on the Mac Pro is says 1920x1200.
On the Mac Mini it says 1920 x 1080 which I presume is because of the internal graphics?
Can I change anything on either the Mac Mini or monitor to improve the picture?
 

getrealbro

macrumors 6502a
Sep 25, 2015
604
262
This is almost certainly a cable/monitor problem. My 2018 Mini's internal graphics handles two monitors, both higher resolution than 1920x1080. The BenQ is attached via USBc<->Display Port and the DELL is attached via USBc<->DVI cable.

You can adjust the resolution of a monitor using System Prefs>Displays>Scaled

GetRealBro

DIsplays.png
 
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flyman

macrumors regular
Original poster
Jan 28, 2004
114
0
This is frustrating, I tried an older hdmi and it made no difference. Both cables I bought weren't cheap and reluctant to want to buy more if its the monitor!
When I go into system prefs theres no option to change to 1920 x 1200, so I'm using 1080p.
I read on another post somewhere that the an older Mac mini has an issue driving displays with non-coherent TMDS receivers in them above a certain frequency, not sure if that applies to my monitor?
 
This thread is so appropriate for me. I plan on purchasing a new 2018 Mac Mini soon, most likely this model:


I have been using a trusty Sony SDM-S93 19" monitor since February 21, 2004, first with a Mac Pro, and then with my current late 2012 Mac Mini. I am having no issues at all with the monitor, and it just seems to keep going and going and going .... And while it's not a Retina display, nor the latest and greatest technology, it still satisfies my needs:


And of course I realize that I will need to purchase an adapter like this one:


My monitor needs are not that demanding, but I would appreciate any recommendations for a replacement monitor. I'm not even sure what size to get, nor what specs to look for. So any advice, information, etc, would be appreciated.

Again, though, I am having no issues at all with the Sony monitor, and it works like a charm.
 

getrealbro

macrumors 6502a
Sep 25, 2015
604
262
This is frustrating, I tried an older hdmi and it made no difference. Both cables I bought weren't cheap and reluctant to want to buy more if its the monitor!...
As I’ve posted before…
My 1920x1200 DEL2407WFP does NOT work at all when attached via the HDMI port — black screen with a complaint from my DELL asking me to set the computer to output 1920x1200! But the same DELL works just fine when attached via this USBc<->DVI cable.


Note: the write up specifically lists “Up to 1920x1200@60Hz”

GetRealBro
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,483
12,614
OP:

Go back to my reply 2 to you above and re-read it.

Also...
DISCONNECT the display from the Mac Pro for now until you get the problems resolved.
When trying to diagnose a problem, remove as many "externals" as possible to narrow things down.
 
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getrealbro

macrumors 6502a
Sep 25, 2015
604
262
i picked up a DELL P2312H monitor for $3 at the local thrift yesterday. It’s working fine at 1080p when attached to my 2014 Mini “headless” server via an HDMI<->DVI cable. :)

So I gave it a try on my 2018 Mini using the same cable ...
1 - the 2018 Mini recognizes the P2312H as 1920x1080 @ 60Hz
P2312H on 2018 Mini.png
2 - it even gives me the option for a few other scaled resolutions
but
3 - the DELL monitor is not happy and displays “The current input timing is not supported by the monitor display. Please change your timing to 1920x1080@60Hz or any other monitor listed timing as per the monitor specifications” regardless of the scaled resolutions selected in System Prefs>Displays.

This is the same problem I had with my Dell 2407WFP monitor when it was attached to the 2018 Mini using the same HDMI<->DVI cable. So it may be that the HDMI<->DVI cable, that works fine with 2 different Dell monitors on the 2014 Mini, is somehow incompatable with the 2018 Mini's HDMI port. OR it may be the problem is the 2018 Mini’s HDMI port.

GetRealBro
 
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Floored

macrumors newbie
Jan 17, 2020
19
4
Probably not much help but I've noticed since updating to 10.15 the Startup screen on my machine has a 'That's All Folks' set of concentric circles around the Login box that cover the screen just like good old 8bits used to. I'm also having other screen issues too so I think another update is on the cards if apple pull their fingers out?
 

dilgil

macrumors newbie
May 4, 2009
4
2
Summary:
Boot-up, black screen at log-in
Mac Mini 2018 (3.2 GHz 6-core i7)
LG Flatiron L227W display from 2008
HDMI to DVI-D
Catalina OS

This is about a display problem with my Mac Mini 2018.

When I boot up from cold, the display screen is blank. It’s black. I do not see the normal log-in prompt. I see nothing. My solution is to disconnect the display cable, wait a moment, and when the monitor tells me it’s getting no signal, then I re-connect the cable. And only then will I see the log-in prompt screen.

I can log-in blindly when the screen is black, but after logging in, the screen will remain black until I disconnect/reconnect the display cable as described above.

I do not have the black screen problem on Restart or when Waking From Sleep. In both cases, the log-in prompt will appear as it should.

I am using the HDMI port on the Mac and the DVI-D port on the monitor with an HDMI-to-DVI-D adapter. I believe that the HDMI cable/DVI adapter/monitor combination is good because I tested it with my old Mac Mini 2014. Using the same cable/adapter/monitor, that old computer behaves normally (with an older Mac OS).

I zapped the PRAM and the SCM on the new Mini. No change. I have never used FileVault. I have no external devices connected to the Mini, other than a bluetooth keyboard and a bluetooth mouse.

My monitor is an LG Flatiron L227 WTS from 2008. I use the standard resolution for the monitor at 1680 x 1050. It offers just two input options: DVI-D and D-SUB (aka VGA).

I’m beginning to think that I’m not the only person with a black screen at start-up. I see people using USB-C and DisplayPort are having problems too. https://forums.macrumors.com/thread...rtup-when-using-usb-c-to-displayport.2157964/

So, before I spend money experimenting with new cables or a new monitor, does anyone have any ideas? My only option seems to be to wait for Apple to issue a fix, or to return the Mini while it’s still under warranty (to be replaced by another that may have the same problem?).

Thanks all. By the way, aside from this problem the Mini has been a great machine, blazingly fast compared to my old Mini.
 
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getrealbro

macrumors 6502a
Sep 25, 2015
604
262
...So, before I spend money experimenting with new cables or a new monitor, does anyone have any ideas? My only option seems to be to wait for Apple to issue a fix, or to return the Mini while it’s still under warranty (to be replaced by another that may have the same problem?)....
When my 2108 i7 Mini wouldn’t display anything on my my DELL 2407WFP, when it was attached via an HDMI<->DVI cable (which BTW works fine on my 2014 Mini), i too was VERY reluctant to start playing cable roulette in the hopes that some cable would fix this. But switching my DELL to this USBc<->DVI cable made it all go away :)


FWIW I bought this cable because of Amazon’s easy, free return policy in case it didn’t fix the issue.

IMHO the 2018 Mini’s HDMI port is not reliable when attaching older, pre-HDMI/displayport monitors that require an adapter/cable (e.g. HDMI<->DVI, etc.), And I now have two DELL monitors that don't work with my 2018 Mini's HDMI port to back that up.

GetRealBro
 
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dilgil

macrumors newbie
May 4, 2009
4
2
That is very useful information, Mr. Getrealbro. I can't afford a monitor upgrade, but I can afford an $18 cable, especially when you've pre-tested that solution. Thank you so much. You also saved me the trouble of sorting through all the different suppliers of cables. Take care and thanks for responding. Down the road I'll let you know how things turned out.
dilgil
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,483
12,614
dilgil wrote:
"I am using the HDMI port on the Mac and the DVI-D port on the monitor with an HDMI-to-DVI-D adapter. I believe that the HDMI cable/DVI adapter/monitor combination is good because I tested it with my old Mac Mini 2014. Using the same cable/adapter/monitor, that old computer behaves normally (with an older Mac OS)."

^^^^^^^^^^^^^^^^
Here is your problem.
Because "what worked" with the older Mini, may not necessarily work with the new one.

You need to try A DIFFERENT CONNECTION SCHEME.
What you try depends on what type of connections are available to you (on the back of the display).

Do you have displayport on the display?
If so, you could try a USBc (Mini end) to displayport (display end) cable.

Or... try a USBc (Mini) to DVI (display) cable.

Or even try an HDMI (Mini) to DVI (display) cable WITHOUT "an adapter" mixed in.

Your problem -- the "black screen at boot" -- is VERY common in the 2018 Mini.
I have it, too.
In my case, the display will ALWAYS "go black as the OS loads".
But... it will ALWAYS "come back" for the login display.
In my case, I found "success" with an HDMI-to-DVI cable.

Whether or not one experiences this problem seems to have something to do with the wide combination of displays AND connecting cables out there.

Some work fine.
Others, not so good.
It's UP TO YOU to find out which "combination" works for you.

Sounds crazy, but I don't believe even the Apple hardware/software engineers have found the solution to this yet...
 

getrealbro

macrumors 6502a
Sep 25, 2015
604
262
...
In my case, I found "success" with an HDMI-to-DVI cable.
...
I'd like to use the HDMI port for my DELL2407WFP and free up a more valuable USBc port. Could you tell us which HDMI-to-DVI cable and monitor combo is working for you?

Thanks in Advance - GetRealBro
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,483
12,614
I'm using an older Viewsonic 27" 1080p display.

The cable? I think it might be this one:

But what works for me... might not work for you.
That's what makes the "black screen at boot" problem so vexing at times.
There doesn't seem to be any "one-size-fits-all" solution.
 

getrealbro

macrumors 6502a
Sep 25, 2015
604
262
Thanks. It might be worth $7 to give that cable a try, since it specifically says that it is “bi directional” and lists support for both 1080p and 1920x1200.

FWIW this is the cable that works with both of my DELL monitors when attached to the 2014 Mini, but not when attached to the 2018 Mini


In reading the writeup, this cable “adapts a DVI output to an HDMI input” Maybe the 2018 Mini’s HDMI port is sensitive to this subtlety and the 2014 MIni’s HDMI port is not.

Edit: I ordered the following cable. It should be here tomorrow.


I post whether it works with my 2018 Mini's HDMI port and DELL monitors.

GetRealBro
 
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dilgil

macrumors newbie
May 4, 2009
4
2
I need to say, thank you, Mr. getrealbro.
You might recall my DVI-D monitor and my 2018 Mac Mini weren’t speaking to each other during boot-up. I wasn’t seeing anything, including the log-in prompt. You suggested a USB-C to DVI-D cable (no adapter needed). Well, I did exactly what you suggested and it worked great.
i too was VERY reluctant to start playing cable roulette in the hopes that some cable would fix this. But switching my DELL to this USBc<->DVI cable made it all go away :)


My lessons learned:
-the 2018 Mac Mini is finicky about adapters
-troubleshooting only gets you so far (I tested my original HDMI-cable-with-DVI-D-adapter on my old Mac Mini 2014 and it worked ok)
-there is no substitute for experience (you knew exactly what to do)
-the MacRumors forum is a great resource
-people like mr. getrealbro who generously offer their time and advice, worthwhile advice, are a treasure.

Thanks.
dilgil
 
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getrealbro

macrumors 6502a
Sep 25, 2015
604
262
I need to say, thank you.... You suggested a USB-C to DVI-D cable (no adapter needed). Well, I did exactly what you suggested and it worked great....
That’s really good news! You are very welcome dilgil. I’m glad the USB-C to DVI cable worked for you too.

BTW - I just received and tested the HDMI - DVI cable that Fishrrman suggested (and only costs $7)



And it also works with my 2018 Mini and both of my DELL monitors. The only problem is that I can no longer use Monitor Control to adjust the brightness on the DELL monitors when they are attached via this HDMI - DVI cable.

GetRealBro

EDIT: OOPS! Posted to soon…
The Benfel cable does work a lot better than the Amazon Basics cable (links in post #18 above). BUT…. I have to unplug and replug it after every reboot :( So I’ve switched back to the Smolink USB-c to DVI cable.
 
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dilgil

macrumors newbie
May 4, 2009
4
2
"what worked" with the older Mini, may not necessarily work with the new one.

You nailed it, mr. Fishrrman. Based on my experience, you are right. I had been using an HDMI-cable-with-DVI-adapter on my old 2014 Mac Mini. I expected it to work on my new 2018 Mac Mini but it did not work well at all (black screen at boot).
I replaced that old cable with a USB-C to DVI-D cable. No adapter needed. It's a cable made by Smolink that was suggested by getrealbro (see previous post).
Thanks for your great advice.
dilgil
 
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flyman

macrumors regular
Original poster
Jan 28, 2004
114
0
Hi Everyone,

I'm a bit late coming back and wow some really useful info posted here so thanks to all of you.

Just to bring you up to speed I disconnected the DVI cable and I've now managed to start up using both the HDMI>HDMI and the USB-C>HDMI albeit with black screen issues as others have mentioned.

I took my Mini to a friends house who has a Dell Alienware AW3418DW monitor. Again tried the same leads and eventually managed to log in with the HDMI>HDMI and the picture looked a whole lot better.?

Try as I may I cannot get my old (2006) BenQ to change resolution to 1920x1200??
 

Floored

macrumors newbie
Jan 17, 2020
19
4
Looking at the manual p46
'Image disruption may occur as a result of signal frequency differences from graphic cards which do not correspond with the usual standard. This is not, however, an error. You may improve this situation by altering an automatic setting or by manually changing the phase setting and the pixel frequency from the “Display” menu.'


Maybe it could be a default setting on the display itself?

Try as I may I cannot get my old (2006) BenQ to change resolution to 1920x1200??
[/QUOTE]
 
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