Older OS MAC new LG monitor not detected

[TGoedde]

I am replacing a burnt out Princeton monitor with a new LG 24MK430H-B monitor. But my MAC OS 10.6.8 is not detecting it. I used an HDMI to DVI cable. If I do a PRAM zapped restart, the monitor fires up and shows the Apple startup screen, but just sits and spools without starting up. Then I do another standard restart and the monitor goes black and the main monitor goes back to work and the system starts up. I have 3 monitors in use. 2 run from a Radeon graphics card with DVI and 1 runs from a USB adapter. All ran fine until one of the monitors plugged into the card power source started to go out. If I switch position of cables it doesn't change anything and the failing monitor will flash the image showing that the card is working fine. The card has both DVI types. 1 has the 24 pins, the other with 2 blocks of 9 pins with a space between them. The HDMI to DVI adapter has all 24 pins. Should I try a VGA to 24 pin DVI adapter instead of the HDMI to 24 pin DVI?

Mac Pro, Quad-Core Intel Xeon, 2.8 GHz, 4 GB ram, ATI Radeon HD 4870 with 518 MB vram.

 

[chscag]

Which Mac (year and model) or are you going to keep us guessing?

 

[TGoedde]

Whoops. Sorry I forgot to add that. See edit

 

[pm-r]

All ran fine until one of the monitors plugged into the card power source started to go out.


I'm not understanding this part. Is the card actually supplying power????




- Patrick
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[TGoedde]

The power source in the monitor is going out. It flashes on and off but shows a signal still being fed to it from the graphics card.

 

[pm-r]

The power source in the monitor is going out. It flashes on and off but shows a signal still being fed to it from the graphics card.

Does it work properly if it is the only monitor connected??




- Patrick
======

 

[TGoedde]

No. It is odd how when I zap the pram the startup apple shows up on the new monitor but my system will not start up or get past the start up apple screen. When I unplug the cable my computer finalizes the start up.

 

[pm-r]

When I unplug the cable my computer finalizes the start up.

And it's known good normally working cable I trust???

I wonder if this is a requirement, but it won't help your 10.6.8 situation:

[Mac OS] OnScreen Control - version 2.86
OnScreen Control is an application to enable easy control of the monitor connected to a PC. Screen Split , Monitor Setting, and My Application Presets and other menus let the user control screen split layout and monitor display settings as well as the monitor picture mode for each application. OnScreen Control is enabled only when a monitor from LG Electronics is connected, with information of the connected display shown on the list of monitors.

Note:
- OnScreen Control supports connection of up to 4 monitors.
- Depending on the connected monitor, supported menu may vary.

Version : 2.86
Supported OS : macOS 10.12, macOS 10.13

http://www.lg.com/ca_en/support/support-product/lg-24MK430H-B


EDIT:
Maybe you just need a more basic monitor that will work with your setup.

But harry may show up with a good solution as he seems to be a Mac Pro guru and probably knows the answer.




- Patrick
======

 

[harryb2448]

The ATI Radeon did not come as standard until the next model, 2009 Mac Pro 3.1.

Is this the Mac Pro model 512GB or a flashed PC 1GB version of the card as they did require two power leads from the logic board?

 

[TGoedde]

It is an upgraded graphic card that I added to the machine. The cord is brand new and does work if I use a USB monitor devices. The USB device could work but has limitations. For example you can't take a screen capture and internet fed apps like Spotify don't show up correctly. Its weird, the Spotify app works, but you can't see the music list in the menu box. As noted previously, the card works and shows images on the monitor I am replacing. The monitor I am replacing is clipping out and the images goes on and off and the image is very faint. If I switch cords from one to the other, both DVI plug in slots work.

 

[harryb2448]

There are two versions of this card. One is the Mac Pro version with 512GB of memory and the other a PC/Saphire card with 1GB of memory. That was the question and is whatever this card may be using two power leads?https://discussions.apple.com/thread/1991909https://discussions.apple.com/thread/1991909

Also have a scan through this re multiple monitors.


https://discussions.apple.com/thread/1991909

 

[TGoedde]

Thanks harryb2448

I ordered a different DVI-D adapter that supposedly will do the trick. We'll see tomorrow what happens with that and report back.