PC to iMac Migration

[BackstageAlex]

At our church, we are moving from using PC to do all our projection to an iMac. Unfortunately, I am having trouble getting the iMac to show up on our screen.

Our signal path runs VGA from the computer to an Extron DVS 304 scaler, then into the switcher, then to the conduit and up to the projectors.

When I switch from the PC to the iMac I get "no signal" on the scaler. The Mac doesn't seem to see the projectors either. I'm using the exact same cable, only connecting it to a VGA-mini DVI adapter to get it to the iMac.

I tried bypassing the scaler and going directly into the projectors. The Mac was then able to detect that external displays were present and even set the resolution, but I was not able to get anything to come up on the screens.

Any ideas?

[Chris Chapman]

When switching back and forth, you may have to power cycle everything once in awhile to get the projector, scaler, etc to reset properly.

When I hook up my Mac to our projector, sometimes I have this issue.

Remember to boot the Mac FIRST and then the outboard stuff afterward.


That may help a little.

[NickJones]

Check the screen resolution, Mac's have a really high one. Your scaler may not be able to handle the signal. Try talking it back to something like 800x600
Nick

[ruinexplorer]

Problem I have had with Macs is that they like to be at a 75Hz display where most everything else will work at 59.94Hz (old NTSC). I agree with Nick that you also need to verify what resolution the Extron can handle, though I don't think you'll need to scale down that much.

I don't know how this particular model of switcher/scaler works, does it save the settings of what's connected? That would make your life a lot easier. Once connected, it would always recognize that source which will make your switching much smoother.

[Studio]

Make sure the mac is set to output to the projector. In system prefrences look for a mirror monitors checkbox in the arrangement tab. If you see 2 monitors then the mac should see the projector. Also check that the adapter cable is firmly connected as they tend to wiggle lose.

[BackstageAlex]

Thanks for all of your input. The computer has started working properly with the cable now, however, anytime I restart the computer or the cable comes out, it takes exactly 6 minutes to get it back up again. Every time.

When using my Macbook Pro, I don't have this problem at all. The display responds immediately. There are only two differences graphics wise between the Macbook Pro and the iMac:

1. Macbook Pro uses an nVidia GeForce card. The iMac uses an ATI Radeon. (Both 256MB)

2. Macbook Pro connects DVI-VGA, whereas the iMac connects mini DVI-VGA.

I figure one of these two items has got to be the problem. Has anyone else ever run into trouble with either of these items?