Member Avatar for Amy M.

Hello,

I just received my new Cinema Display 20" and have it all hooked up.

However, I would like to also run the previous monitor which is a NEC Accusync LCD 17" as a second monitor. I'm told this would be particularly beneficial when using photoshop.

There is only one port on the back of the PowerMac which fits the monitor.

There is another port which has 3 rows of 10 pins which is not being used.

Is there a way I can run both monitors simutaneously?

Thank you in advance.

Amy

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Short summary and safest wiring: follow . by keeping the NEC on the Mac’s DVI output (using the passive DVI->VGA adapter only if the Mac’s DVI port provides analog) and use an active DVI->ADC adapter to plug the Apple Cinema Display into the ADC socket. The Apple DVI->ADC adapter is an active device with its own power and signal conditioning, which is why it usually works reliably where passive chains fail. (apple.com)

How to check the DVI port before you plug things together: look at the DVI connector on the Mac. If there are four small pins surrounding the long flat blade it is DVI‑I (analog + digital) and a passive DVI->VGA adapter will work. If those pins are missing (DVI‑D) the passive adapter will not provide VGA — an active converter is required. The Power Mac G4 documentation also notes that an analog monitor can be connected via a DVI->VGA adapter when the card supplies the analog signals. (nvidia.custhelp.com)

If the ADC->DVI adapter is unavailable or too costly, adding a Mac‑compatible PCI/AGP video card is a valid alternative. Confirm the G4 variant (PCI vs AGP slot) and choose a card that has Mac drivers for your OS X version — many G4s shipped with specific Apple/ODM cards (GeForce/Radeon families) and not all PC retail cards behave the same without Mac driver support. Check model‑specific specs before buying. (leopard-adc.pepas.com)

Cautions and final notes: avoid chaining passive adapters (VGA->DVI passive -> DVI->ADC) because converting analog to digital and back rarely works reliably. ADC and its adapters are legacy Apple hardware; the active adapter’s power and electronics are why the ADC route is the cleaner solution if you can source one. Test each monitor alone first, then set up extended desktop in Displays/System Preferences once both are connected. (en.wikipedia.org)

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Member Avatar for John A

Yeah, although you'll need to add another video card. Get a PCI video card (note that it's just PCI -- PCI Express, or PCI-E for short is a completely different interface), and make sure it has the correct output. If your monitor has a plug that looks like this:
http://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/DVI_Connector.jpg/762px-DVI_Connector.jpg
Then it supports DVI and you should look for a PCI video card which supports DVI output.

If the only monitor input you have looks like this:

Your monitor only supports VGA, and you should look for a video card which supports VGA output. Note that it might also be advertised as SVGA, which is essentially the same thing.

If your monitor supports both, go with DVI as it's a purely digital signal and will therefore result in a higher picture quality.

Member Avatar for Amy M.

Thank you for the great information, John. The pics were very helpful too.

The PowerMac has the DVI connection and while the NEC has a VGA, it came with the DVI adapter, so I am all set for DVI.

I'm going to try to identify what the other connector is on the back of the PowerMac. Now it has made me curious.

Thanks again.

Amy

Member Avatar for Amy M.

Ok, the other connection is an ADC port. It's intention was to enable the use of 2 monitors, but was abandoned after the Power Mac series.

BUT there is a DVI to ADC Adapter still available.

My new question is since the monitor is VGA, but with adapter becomes DVI, is it "safe" to use 2 adapters back-to-back?

In other words, it would be Monitor (VGA) connected to DVI Adapter, which would be connected to the ADC Adapter, and then to the ADC connector in the back of computer.

Would an additional PCI graphics card still be preferable to the Adapter?

Member Avatar for John A

>is it "safe" to use 2 adapters back-to-back?
I doubt it. It gets a little tricky because VGA is analog, while DVI is digital, and converting the signals back and forth a couple of times likely won't work (see ).

A simpler solution would be to connect the NEC Accusync LCD 17" to your PowerMac's DVI port with your DVI to VGA adapter. Then, buy the ADC to DVI adapter and use that to connect your Cinema display to your ADC port.

Member Avatar for Amy M.

Good to know.

Unfortunately, the second and most viable option costs a lot more. Lucky me.

Guess I'm back to the PCI card.

Thanks!

Member Avatar for John A

>Unfortunately, the second and most viable option costs a lot more.
I fail to understand what you mean. An ADC to DVI adapter costs $30 on Amazon:
http://www.amazon.com/Belkin-F2E9142-WHT-Apple-Monitor-Adapter/dp/B000067RLH

Through that adapter, you can connect your Cinema display to your ADC port on your computer.

You said you already have a DVI to VGA adapter, so you can connect your NEC Accusync LCD 17" to the DVI port on your PowerMac.

Or have I missed something?

Member Avatar for Amy M.

I was thinking of the other way around. The ADC monitor to DVI port were around $100.

Yes, the DVI monitor to the ADC port are much more reasonable. Thanks for pointing it out.

By going from DVI (monitor) to ADC port, is it likely to sacrifice any picture quality?

Member Avatar for John A

>By going from DVI (monitor) to ADC port, is it likely to sacrifice any picture quality?
Nope, because the image signals that run through the ADC are digital (as compared to the purely analog VGA). ADC essentially is DVI with a few add-ons thrown in.

Member Avatar for Amy M.

Thanks!

I think I'm good to go!

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