Trouble with early PowerMac G4 and 23" acrylic Cinema Display

[bobesch]

A friend of mine got a PowerMac3,3 G4 400 (Gigabit) with standard ATI Rage 128 Pro graphics card.
He also was lucky to score an acrylic 23" acrylic cinema display.
Unfortunately the cinema display doesn't work, when connected to the PowerMac through ADC.
I happened to have the same problem with my Cube G4.
Is it related to the lower resolution of the PowerMac's graphic-card compared to the higher resolution of the Cinema Display
and are there any workarounds or solutions to sort that out?
Thanks for help!

​

 

[Amethyst1]

Is it related to the lower resolution of the PowerMac's graphic-card compared to the higher resolution of the Cinema Display
and are there any workarounds or solutions to sort that out?

Yep. The Rage 128 Pro’s DVI port (more precisely, the TMDS transmitter that drives the DVI port) cannot “do” 154 MHz pixel clock, which is necessary to run the 23” at full resolution and 60 Hz refresh rate. Since the display doesn’t have a built-in scaler, it doesn’t support any lower resolutions either.
You need a newer graphics card or you can try hooking up the display to the Rage’s VGA port using a VGA to DVI adapter plus a DVI to ADC adapter (like this).

 

[eyoungren]

Yep. The Rage 128 Pro’s DVI port (more precisely, the TMDS transmitter that drives the DVI port) cannot “do” 154 MHz pixel clock, which is necessary to run the 23” at full resolution and 60 Hz refresh rate. Since the display doesn’t have a built-in scaler, it doesn’t support any lower resolutions either.
You need a newer graphics card or you can try hooking up the display to the Rage’s VGA port using a VGA to DVI adapter plus a DVI to ADC adapter (like this).

In regards to the DVI/ADC adapter, wouldn't an A1006 with a VGA to DVI adapter work?

 

[bobesch]

In regards to the DVI/ADC adapter, wouldn't an A1006 with a VGA to DVI adapter work?

The VGA adapter does work with another display. We are going to cross-check the function of PowerMac and Cinema-Display tonight or tomorrow using the adapter(s), a smaller 15" Cinema-Display and a later PM-G4 which has a graphic-card, that has proved to work with the 23" display.
Problem is, that my friend needs to get an A1006, which is more expensive, than PM and 23" display together and harder to find. So I wonder, if there's a solution to make the 23" display work through ADC despite of the lower resolution.

 

[bobesch]

Yep. The Rage 128 Pro’s DVI port (more precisely, the TMDS transmitter that drives the DVI port) cannot “do” 154 MHz pixel clock, which is necessary to run the 23” at full resolution and 60 Hz refresh rate. Since the display doesn’t have a built-in scaler, it doesn’t support any lower resolutions either.
You need a newer graphics card or you can try hooking up the display to the Rage’s VGA port using a VGA to DVI adapter plus a DVI to ADC adapter (like this).

Ah, thanks for the information!
(I started reading here this morning from the bottom to the top and missed your answer in first place ... ?)
Well, unfortunately that's a disappointment ?, because I also unsuccesfully tried to connect a 23" display to my Cube G4 some time ago.
So we are definitely going to check, if the VGA to DVI to ADC adapter-chain will work ...

 

[Amethyst1]

In regards to the DVI/ADC adapter, wouldn't an A1006 with a VGA to DVI adapter work?

Yep, or Dr. Bott's VGAtor (VGA-to-ADC) adapter, if you can find one.
The VGA-to-DVI (or VGA-to-HDMI) adapter needs to be this particular direction, a passive DVI-to-VGA adapter won't work.

So I wonder, if there's a solution to make the 23" display work through ADC despite of the lower resolution.

You can try reducing the refresh rate to stay within the pixel clock limits of the Rage 128 Pro. It can “do” 1600×1024 at 60 Hz for the 22", i.e. 112.27 MHz pixel clock, which is enough for 44 Hz at 1920×1200 using CVT-RB timings. However, I'm not confident the 23" accepts refresh rates that low — it accepts 57 Hz, but 44 Hz is another pair of shoes.

So we are definitely going to check, if the VGA to DVI to ADC adapter-chain will work ...

It worked with a PowerBook G3 (Pismo)’s 8 MB Rage Mobility 128, so the 16 MB Rage 128 Pro should have no issues.

 

[TheShortTimer]

Yep, or Dr. Bott's VGAtor (VGA-to-ADC) adapter, if you can find one. The VGA-to-DVI (or VGA-to-HDMI) adapter needs to be this particular direction, a passive DVI-to-VGA adapter won't work.

Here's one. I've been searching for this adapter for a long time but the price is too high imho - that's without even considering the import charges and postage. Maybe I'll regret passing it up but oh well.

 

[Amethyst1]

Here's one.

That’s a DVIator, i.e. DVI to ADC — same as Apple’s A1006 but with compatibility issues. No thanks.

 

[TheShortTimer]

That’s a DVIator, i.e. DVI to ADC — same as Apple’s A1006 but with compatibility issues. No thanks.

Yet the seller has described it as an ADC to DVI.

Return and refund scenario...

Thanks for the clarification.

 

[Amethyst1]

Yet the seller has described it as an ADC to DVI.

What I love about Dr. Bott’s adapters is how they solved the problem of powering ADC displays: by throwing in the original G4 Cube power supply. Brilliant.

 

[TheShortTimer]

What I love about Dr. Bott’s adapters is how they solved the problem of powering ADC displays: by throwing in the original G4 Cube power supply. Brilliant.

So that's what it is! I was confused about the Apple logo and the Dr. Bott badging. You'll have to excuse my ignorance as I haven't dabbled with the G4 Cube.

On reflection that listing isn't a bad deal for the G4 Cube PSU alone - it's considerably cheaper than what the unit goes for elsewhere.

 

[Amethyst1]

You'll have to excuse my ignorance as I haven't dabbled with the G4 Cube.

Nothing to apologise for — I haven’t gotten my hands on a Cube yet either but was curious about what PSU they used.

On reflection that listing isn't a bad deal for the G4 Cube PSU alone

Indeed. I wonder how many people looking for a Cube PSU are aware of this possible deal.

 

[bobesch]

That’s a DVIator, i.e. DVI to ADC — same as Apple’s A1006 but with compatibility issues. No thanks.

Crazy product! Allows You to use two Studio-Displays with the Cube and has that fancy case!

 

[Amethyst1]

Crazy product! Allows You to use two Studio-Displays with the Cube and has that fancy case!

The VGAtor does, since the Cube has VGA and ADC. The “case” is actually the PSU, the adapter itself is just a not-very-pretty-looking (not that this matters ) cable.

 

[ervus]

A friend of mine got a PowerMac3,3 G4 400 (Gigabit)...

Are you sure it's a "gigabit" computer? The 400MHz G4 also came in the AGP model. So it's possible to put an ADC video card in an earlier model and it will work, except the ADC card won't have 28v to power the monitor through the card. I made an identification guide in this thread:

CPU Upgrades - The PowerMac G4 Digital Audio (DA)

Hello! Currently, I have not seen someone confirm a Gigabit Ethernet CPU working in a Digital Audio. I have seen Gigabit Ethernet G4 CPU's around on eBay and some are even dual CPUs. This one I'm looking at here being at dual 800Mhz. eBay Link This reportedly being compatible with the...

forums.macrumors.com

 

[bobesch]

Are you sure it's a "gigabit" computer? The 400MHz G4 also came in the AGP model. So it's possible to put an ADC video card in an earlier model and it will work, except the ADC card won't have 28v to power the monitor through the card. I made an identification guide in this thread:

CPU Upgrades - The PowerMac G4 Digital Audio (DA)

Hello! Currently, I have not seen someone confirm a Gigabit Ethernet CPU working in a Digital Audio. I have seen Gigabit Ethernet G4 CPU's around on eBay and some are even dual CPUs. This one I'm looking at here being at dual 800Mhz. eBay Link This reportedly being compatible with the...

forums.macrumors.com

Oh, thank for Your information! I've checked Your pictures from Your other posting and, yes, it's a 400MHz Gigabit PM-G4.
Today we made a testdrive with both PM and the 23" ACD. Both worked fine.
The PM was checked in combination with a 15/17" acrylic StudioDisplay.
The 23" ACD was checked with the Apple DVI/ADC-adapter and my 17" early'08 MBP (DVI-out)

Unfortunatly we couldn't connect the 23"ACD through the Apple DVI/ADC-adpter to a VGA-port, because I hadn't the right adapters.
PM/VGA-socket(f) <> (m)VGA-cable(m) <missing adapter> (m)DVI-ADC-adapter

 

[Amethyst1]

Unfortunatly we couldn't connect the 23"ACD through the Apple DVI/ADC-adpter to a VGA-port, because I hadn't the right adapters.
PM/VGA-socket(f) <> (m)VGA-cable(m) <missing adapter> (m)DVI-ADC-adapter

I thought you have a Matrox DualHead2Go? If it's the version with a VGA input and two DVI outputs, you can also use that. Connecting a single monitor makes it behave like a VGA-to-DVI adapter.

 

[bobesch]

I thought you have a Matrox DualHead2Go? If it's the version with a VGA input and two DVI outputs, you can also use that. Connecting a single monitor makes it behave like a VGA-to-DVI adapter.

Good idea - that didn't come to my mind ?
On the other hand, I do not want to give away my Matrox adapter.
Haven't even got the time / occasion to try it out ... ?