VGA Out not working with long VGA cables

I bought a Macbook Pro with Tiger more than a year ago and I'm very happy with it except for one thing.

I do a lot of presentations and I have a problem that, when the vga cable to the proyector is very long (example: when the projector is installed in the ceiling of the room) my Mac tries to detect it (I see the screen for a moment) but comes back to just the main screen without VGA out.

It's not a problem of the projector or the cable because the windows laptops work fine and we can see the mac image in the projector for about a second. I tried to detect screens several times but it's allways the same.

I guess it's something about the impedance of the cable (because of the length) or something like that but I can't change it because it's allready installed.

¿Is there any way to force the VGA out of the Macbook pro?

Thank you

Is the extender cable really cheap - perhaps you should look at a better quality VGA cable.

As you say, might be a power issue. You can buy boosters - but the seem to cost silly money

louishen said:

Is the extender cable really cheap - perhaps you should look at a better quality VGA cable.

As you say, might be a power issue. You can buy boosters - but the seem to cost silly money

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But I can't change the VGA cable. I just get to the room (different each time) and plug the cable that goes to the projector through the ceiling (wich is already installed).

About the boosters, the signal seems to get well to the projector (I see the image for a second while it detects screens) and the windows laptops work well in the same situation.

I think that I need some kind of software or hardware (I prefer software) that tells Tiger to output signal even without a VGA cable pluged in.

use another persons laptop for presentations, or even the desktop thats in the classroom maybe?

stupid fix, but it is what it is

kgeier82 said:

use another persons laptop for presentations, or even the desktop thats in the classroom maybe?

stupid fix, but it is what it is

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That's what I've been doing, but I prefer to use mine because there is no "keynote" in Windows. If I cannot use the advantage of a Mac because I need another computer to work, ¿What is the point to use it?.

anorod said:

That's what I've been doing, but I prefer to use mine because there is no "keynote" in Windows. If I cannot use the advantage of a Mac because I need another computer to work, ¿What is the point to use it?.

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there really isnt an option here. Youre given the chance to use classroom projectors that just dont work with your machine.

Some times the result just doesnt justify fixing the problem. If all it is is a simple ppt presentation, your mac doesnt hold any advantage to a standard pc. anything can do ppt fine.

cant keynote save as ppt?

im afraid that you just have to do the best with what you have. why try to throw money at a problem, that quite frankly you may not have in a semester? temperary fixes are sometimes better in the long run

You can always buy your own projector.

Conclusions for now

Right now I see the following options:

• Buy a projector (not worthy and I cannot use it in all the places)
• Use a Windows laptop because the Macbook can't handle the VGA out with long cables (Are you seriously telling me that?)

About the ppt, kgeier82. I use keynote because I love the program. It can export to ppt, but the images and transitions are very poor in the ppt. I normaly export to pdf and use a full view in the windows acrobat reader (can't see the videos with this method ).

¿Is there anyway (software or hardware) to force the VGA out?

Okay so this might be stupid, but if your projector shows the desktop for a sec and then switches to blue, thats what my mbp does when its in dual screen mode.

You might want to go to display preference and make sure that you have Mirrored Screens checkmarked.

Like you may be seeing an extension of your desktop on the other side and not have noticed. Just make sure you have mirroring on.

Oh and btw, for some reason, like as with our school, some of the projectors will only display os10 in 800x600

not many other options, im out of ideas

good luck!

milessthomas said:

Okay so this might be stupid, but if your projector shows the desktop for a sec and then switches to blue, thats what my mbp does when its in dual screen mode.

You might want to go to display preference and make sure that you have Mirrored Screens checkmarked.

Like you may be seeing an extension of your desktop on the other side and not have noticed. Just make sure you have mirroring on.

Oh and btw, for some reason, like as with our school, some of the projectors will only display os10 in 800x600

Click to expand...

Good point (thinking different about the problem to find a solution) but it's not my case :S. I normally work with dual monitor and have different wallpapers in each screen. In that second I see the wallpaper of the second monitor.

Neither is the resolution because I've used the same projector in other classes and they work fine (I suppose they have shorter cables installed).

kgeier82 said:

not many other options, im out of ideas

good luck!

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Thank you very much for your ideas. Right now I'm doing what you said but I was tired of the doubt "will it work here?" and exporting the presentations to pdf.

Besides, It's sad to listen some people senteces like "That's because you use Mac, with Windows is completely compatible".

Not to harp on the same point, but have you checked Displays in System Preferences when this happens? I one time had that happen with my Mac Mini and some funky cables and was able to force it back on. I might be wrong but Miles has a good point.

dtravis7 said:

Not to harp on the same point, but have you checked Displays in System Preferences when this happens? I one time had that happen with my Mac Mini and some funky cables and was able to force it back on. I might be wrong but Miles has a good point.

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When the problem happened I opened the system preferences and tried to "Detect Screens". I don't know how to change the second display preferences when the Mac doesn't detect the second screen.

Anyway, I'll try to get in one of the rooms and check what you said.

Thank's. I'll keep up with the results

anorod said:

Good point (thinking different about the problem to find a solution) but it's not my case :S. I normally work with dual monitor and have different wallpapers in each screen. In that second I see the wallpaper of the second monitor.

Neither is the resolution because I've used the same projector in other classes and they work fine (I suppose they have shorter cables installed).





Thank you very much for your ideas. Right now I'm doing what you said but I was tired of the doubt "will it work here?" and exporting the presentations to pdf.

Besides, It's sad to listen some people senteces like "That's because you use Mac, with Windows is completely compatible".

Click to expand...

once they release that comment, why dont you show them windows in bootcamp, and then show them your method of AV protection/scanning in OSX.

buttfaces really.

If you have leopard you can open system preferences then hit multiple desktops and drag the 2nd screens system preferences panel to the main screen. I don't know if theres another way to pull all windows though.

milessthomas said:

If you have leopard you can open system preferences then hit multiple desktops and drag the 2nd screens system preferences panel to the main screen. I don't know if theres another way to pull all windows though.

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if the screen isnt detected like he is saying, you cant do this.

kgeier82 said:

once they release that comment, why dont you show them windows in bootcamp, and then show them your method of AV protection/scanning in OSX.

buttfaces really.

Click to expand...

Yeah, I know. They can't "think different" . When I have an presentation with a group, I normaly show them Keynote and they just say "we're going to use that, it's great!".

Just need that final part of the VGA out to make it perfect

milessthomas said:

If you have leopard you can open system preferences then hit multiple desktops and drag the 2nd screens system preferences panel to the main screen. I don't know if theres another way to pull all windows though.

Click to expand...

Uhm.. But to do what you say I need the second screen active (to have the second screen menu) and that doesn´t happen more than a seccond.
I can configure it with another monitor, but I think that MacOs uses different configurations for different screens.


Thanks to all!