Welcome to the MacNN Forums.

Uncle Skeleton · Jun 9, 2009, 09:13 PM

I got a VGA splitter for my home theater mac mini, so I could watch on the projector and then go into the kitchen and still see things on an LCD in there. Also to put up recipes. Anyway, when I connect the splitter, the image on the projector gets darker (maybe half brightness?). The monitor is a little darker but it doesn't matter there. I can jack up the brightness and contrast through the projector menus, and that almost makes up for it, but not quite and also then the picture looks kind of washed out.

Does anyone know the cause or how to remedy it? Thanks

ghporter · Jun 9, 2009, 09:40 PM

Is the splitter powered? How long are the cables? Does the kitchen LCD look dark then too? It sounds like the signal getting to the projector is attenuated by either the splitter circuitry or the length of cable.

Uncle Skeleton · Jun 9, 2009, 10:55 PM

Unpowered, the kitchen cable is 50', the projector's is 6', the splitter is about 0.5', and the DVI->VGA adapter (Apple) is about 1". I tried swapping the 50' for another 6', no change. The LCD is also about half as bright as otherwise, but that doesn't bother me because it was more than bright enough already.

ghporter · Jun 10, 2009, 07:41 AM

So it sounds like that unpowered splitter is the cause of the dimming. Powered splitters aren't horribly expensive; maybe you should look into one of those. I used such a device about 11 years ago (had to fabricate the cable to the projector by hand), and it worked great.

mduell · Jun 10, 2009, 02:29 PM

Intel or PPC mini?

ghporter · Jun 10, 2009, 02:37 PM

Originally Posted by mduell

Intel or PPC mini?

Different video systems on the two, right? Which would imply different capabilities for driving logic levels? Still, 50' of cable is a lot without powering a splitter, don't you think?

Uncle Skeleton · Jun 10, 2009, 03:06 PM

It's a 1.66 core2duo (a refurb mini), not sure of the graphics card.

I don't need to use the 50', a 6' would do if necessary. It just doesn't seem to change anything when I try it as-is.

ghporter · Jun 10, 2009, 03:17 PM

Have you tried it with only one 6' cable on the splitter?

Uncle Skeleton · Jun 12, 2009, 09:59 AM

Huh. That fixes it. What does that tell us?

ghporter · Jun 12, 2009, 10:21 AM

Originally Posted by Uncle Skeleton

Huh. That fixes it. What does that tell us?

That either the other cable has a problem, or that the splitter can't push the signal through the longer cable without loading so much that both outputs are pulled down, thus decreasing the brightness of the image from both outputs. This is exactly why a powered splitter is a better solution; the two (or more) outputs are not only isolated, but usually provided with enough power to push the signal through longer cables.

mduell · Jun 12, 2009, 06:16 PM

Originally Posted by ghporter

Different video systems on the two, right? Which would imply different capabilities for driving logic levels? Still, 50' of cable is a lot without powering a splitter, don't you think?

The PPC mini was known to have below-spec voltages on the VGA output.

Sounds like his problem is just a bad cable or splitter.