strange blue screen problem

[estmn]

I am currently setting up and operating a video system for a theatre production..

 

The setup we are using is a DLP BenQ projector

iMac G5, with a forced extended desktop - through use of a patch

a VGA extender running a 30m cat5 cable in between.

 

The sysem is brilliant, but during shows, the projector loses signal for about 1 second. usually around the same place in the video. We are unsure as to what it could be. we've tried everything, replaced all the cables, taking out all the equipment we didn't need, and it still does it.

 

If anyone has any ideas as to what this could be, please let me know, cause we're stumped.

[mac.calder]

Does it play okay on your mac without extending?, what about on another computer? Have you tried a different file? Are all cables in good condition - tight connections? Is there something going on at about that point that could be effecting signal?

[MarcT]

Screensaver? Monitor power saving mode (DPMS) ?

 

Just a thought...

[ian@prl]

To eliminate projector replace with a TFT screen,have you tried using VGA instead of CAT5 extenders.

[bruce]

Coincidence or what - today I came across a virtually identical problem!

 

5 identical installations, all exhibiting the same fault.

 

Brand new installation, small lecture theatres - using active vga & composite extenders. Small wall-box with vga, composite and audio input, secondary box on roof beside projector, 2 lengths of CAT5 between them.

 

Works well - good picture.

 

BUT, there's also an electrically-operated screen. When you raise or lower this (specifically, when you turn the motor OFF) the screen goes blank for a couple of seconds while the projector re-adjusts. You also get a click on the audio.

 

We're getting the installation company back in to investigate, but it looks like maybe inadequate suppression on the screen motor, or some sort of back-emf, is interfering with the extender.

 

Bruce.

[JCoster]

The sysem is brilliant, but during shows, the projector loses signal for about 1 second. usually around the same place in the video. We are unsure as to what it could be. we've tried everything, replaced all the cables, taking out all the equipment we didn't need, and it still does it.

<{POST_SNAPBACK}>

Erm... If I recall correctly, this is because the projector is automatically updating the signal or something... This happens on my Pioneer 43" plasma every now and then... It searches for new signals that could improve the quality... This could be a load of rubbish but I'm not too sure...

[jcgoldcoast]

A half-fix to the blue screen problem is to set the black screen colour to black, rather than blue, it wont get your image back for that second, but looks a hell of a lot better than having blue up on the screen. From memory, in the BenQ projectors it is in the setup menu (can anyone verify this?)

[viktorkr]

Could you please explain in detail what you are doing with computer (which software are you using, in which resolution etc.) because it seems to me that when you try to play video, software automatically changes the resolution, and of course the projector losses sync for that time of change. I am using one specifical software for subtitling which works only on 800 x 600, and when I start the subtitling, software immediately changes the resolution.

If this happens to you in the middle of video, then it is not a problem of that kind, but if happens before or after or especially before and after video, try to find solution in stopping the software to make automatic changes.

Good luck.

Viktor