Mm 1,1-6,2 Mac mini 2006 on modern display via DVI to HDMI adapter?

[BanjoDudeAhoy]

Hello. I wonder if anyone has some insight.

I have a (late) 2006 Mac mini here as a bit of a project to upgrade hardware and run old stuff on. It’s a delightful little machine.
It works fine on a 40” 1080p TV and a 24” 1080p monitor with a DVI to HDMI adaptor.

But when I hook it up to a 27” 4K display, no matter what what HDMI cable I use, the display tells me there’s no signal. Now, afaik this mini is supposed to support a max resolution of 1920x1200 but I figured my display would adjust to that and automatically switch to a resolution they both support.

Does anyone know what’s happening here? Is the display maybe just too new and high res to be supported by this old mini?

 

[Amethyst1]

If the display’s EDID also contains a 1080p or lower mode with a pixel clock of <=165 MHz the mini should use that.

What display is it? I used a Dell P2415Q with my 2006 mini at 1080p but don’t quite remember if it was via DisplayPort or HDMI. Probably DisplayPort though. I do remember not getting any signal until OS X‘s login screen appeared on the first boot. But that was fixed on subsequent reboots.

Can you screen-share into the Mac mini while the display is connected and use SwitchResX to

• see what mode it’s trying to run on the Current Resolutions tab
• try to switch to another mode on that same tab to hopefully find one that works
• export the display‘s EDID so I can see what modes it presents to the computer (this can also be done on a more modern machine)?

 

[BanjoDudeAhoy]

If the display’s EDID also contains a 1080p or lower mode with a pixel clock of <=165 MHz the mini should use that.

What display is it? I used a Dell P2415Q with my 2006 mini at 1080p but don’t quite remember if it was via DisplayPort or HDMI. Probably DisplayPort though. I do remember not getting any signal until OS X‘s login screen appeared on the first boot. But that was fixed on subsequent reboots.

Can you screen-share into the Mac mini while the display is connected and use SwitchResX to

• see what mode it’s trying to run on the Current Resolutions tab
• try to switch to another mode on that same tab to hopefully find one that works
• export the display‘s EDID so I can see what modes it presents to the computer (this can also be done on a more modern machine)?

It’s a Philip 278E1A.

Maybe it’s because I’ve not used SwitchResX before, but I’m a little lost. How do you mean screen-share int the Mac mini?

 

[BanjoDudeAhoy]

Okay, I ran SwitchResX from another machine on the same monitor and it lists this in the exported EDID document:

Detailed Timing Block #2 - Timing definition:
Mode = 1920 x 1080 @ 60.000Hz
Pixel Clock............. 148.50 MHz Not Interlaced

EveryMac.com says about the 2006 Mac mini

supports coherent digital displays up to 154MHz; supports non-coherent digital displays up to 135MHz

Do these listed frequencies have anything to do with the Pixel clock?
Here's the rest of the exported document from SwitchResX.

 

[Amethyst1]

How do you mean screen-share int the Mac mini?

You need to see the mini's screen and control it when it's connected to the 4K monitor. It needs to be networked to another computer for Screen Sharing to work. Using a monitor that works with the mini, go to System Preferences > Sharing and turn on Screen Sharing. Then, connect to the mini from another Mac using the Screen Sharing app (use Spotlight to locate it). If that doesn't work because the macOS versions on the two machines are too far apart (I've never tried it), try going into the advanced screen sharing settings on the mini and enabling the VNC option. Then connect from the other Mac using Finder: Go to > Connect to server and enter vnc://1.2.3.4 where 1.2.3.4 is the mini's IP address.

Maybe it’s because I’ve not used SwitchResX before, but I’m a little lost.

The 4K monitor needs to be connected to the mini and you need to be screen-shared into it. After launching SwitchResX, select the monitor in the left part. There is a Current Resolutions tab on the right. Select it and you'll get a list of resolutions; the one the mini is currently outputting has a radio checkbox next to it. The idea is to

• see what resolution the mini is trying to output to the monitor (which doesn’t work)
• try lower resolutions which have a lower pixel clock until you hopefully find one which works
• (optionally) define a custom timing, such as 1920×1080@58Hz CVT-RB, to stay under the mini's pixel clock limit (assuming it is 135 MHz; see next paragraph).

Do these listed frequencies have anything to do with the Pixel clock?

Yes, they refer to the pixel clock. 1920×1080@60Hz is 148.5 MHz using HDMI timings so if your display is non-coherent (I have no idea how to determine if it is or not) that won't work. Lower resolutions up to 1280×1024@75Hz should™ work though since they are ≤ 135 MHz and your display's EDID contains a bunch of them; although you provided the DisplayPort EDID and the HDMI EDID is different, there’s hope it has a bunch of lower resolutions in it too.