Display gurus requested!

[philgxxd]

Hi.
I could need some help with an issue i’m trying to solve for quite some time now. It’s not that I digged deep into it but every now and then I came back to it.
It involves a KVM switch and a Apple 17” ADC LCD Studio display.
I use a known working Apple DVI to ADC converter and a known working Gefen VGA to DVI scaler.
The source I’m having trouble with is my B&W G3 Tower with a Rage Pro (only 1 VGA output).
My other two sources, a G4 MDD and a PC tower are getting a picture on the Studio Display through the KVM switch.
The B&W won’t output a picture through my setup.
I tried to setup the specific (max. resolution) of the Studio Display which is 1280x1024 through a temporary connected CRT monitor (connecting the CRT directly to the B&W G3) but that didn’t change anything.
The Studio Display always stays black.
By the way, the setup is working when I connect my other LCD 22” Cinema Display which seems more forgiven with resolution problems.

Paging @Amethyst1 here as I know he tried it all but I’m hopeful any member could maybe guide me to a solution.

 

[Doq]

Have you tried with a different video card in the G3? The Rage Pro may be outputting something that either the KVM or the Studio Display doesn't like (even though the resolution is correct, could be possible refresh rate or clock timing).

 

[DearthnVader]

I can't really offer much help here other than to say the B&W is likely not reading the EDID data correctly.

With the setup installed it would likely help to Remote Desktop into the B&W and see what data the display devices are sending the B&W.

With OS X there are some EDID overrides that can help, with OS 9 or older I think SwitchRes can do pretty much the same thing.

But the first step is seeing what data if any the B&W is getting from your KVM.

 

[philgxxd]

@Doq I will try with a Matrox card I have. It’s from 1997 and probably have even less memory than the Rage but it’s the only other PCI card I have.

@DearthnVader That is a good idea and I tried once a VGA splitter I brought home from work only to find out that the second port was not working…It’s running Mac OS 8.6 so I have to find out what Remote Desktop solutions I have to install. Thanks.

 

[philgxxd]

B&W G3 don’t support Firewire target mode, do they?

 

[Doq]

It should, if you hold down the T key at startup (just like every other Mac with FW).

 

[Amethyst1]

Paging @Amethyst1 here as I know he tried it all but I’m hopeful any member could maybe guide me to a solution.

Oh, the honor My advice would also be to Timbuktu into the box with the Studio Display connected to it, use SwitchRez2 to see what mode the box is using and to try setting it to 1280×1024@60Hz.

 

[philgxxd]

I have the remote software and SwitchRes2 installed on my B&W G3 and can see what I’m doing on my PowerBook with 10.4 Tiger and Timbuktu Pro 8.
I can verify that the resolution is set to 1280x1024 60Hz but the 17” LCD Studio Display still remains black.
When I hotplug my 20” Cinema Display to the G3 I get a picture and I can even see the menu of my VGA to DVI scaler when I press the physical menu button.

Is the 17” LCD Studio Display known to be picky?

As a reminder:
I’m using a Gefen VGA-DVI scaler to convert the output of the Rage128Pro 16MB from my B&W G3 tower going into a Gefen 4x4 DVI KVM matrix switch which gives me a picture with my other two DVI sources, a G4 MDD and a PC.

 

[Amethyst1]

I can verify that the resolution is set to 1280x1024 60Hz but the 17” LCD Studio Display still remains black.

Maybe it’s using a timing standard the display doesn’t like.
Does its LED provide any error code?
Does SwitchRes2 allow you to examine the actual timing like SwitchResX does on OS X?
Does the Gefen scaler show anything like that?
You could use SwitchResX on your G4 to see the actual timing the display works with, but that won’t help with the problem since SwitchRes2 doesn’t allow defining custom timings.

When I hotplug my 20” Cinema Display to the G3 I get a picture and I can even see the menu of my VGA to DVI scaler when I press the physical menu button.

At what resolution(s)/refresh rate(s)?

 

[philgxxd]

Hi.
Thanks a lot for the assistance.

So i connected the display to a MBP4,1 with SwitchResX temporary installed and i will attach the EDID dump here.
The LED of the monitor is just ON as soon as i have the Gefen KVM switch matrix operating. When i switch to another VGA-HDMI scaler i have i can make that the LED of the monitor is blinking 3x times as soon as i play with the output settings but with the current one it's just behaving like i described.
The scaler menu when it showed up on the other 22" Cinema Display is just giving the resolution and refresh rate.
I didn't change the resolution when i connected the Cinema display. It was still 1280x1024@60Hz from the B&W G3.

 

[philgxxd]

Bump @Amethyst1