CurtPalme.com Home Theater Forum

WayneB

I have a newly installed ceiling mounted Marquee 9500LC Ultra and a 16x9 72inch wide screen.
I just noticed a prism-like (multi-colored) light about 24 inches below the screen.
It may have been there for the last month (since I installed the projector), but I just noticed it yesterday. Embarassed

What the heck is it?

It is definitely coming from the lenses. I can hold a piece of white paper in the light path and follow it back up to the lenses. It happens on all signal sources (1080i satellite, 1080p DVD, and all test images from the Marquee).

I took the following pictures in a totally dark room, using "night scenery" and the count-down timer, then modified them in Photoshop Elements to brighten the image so it is easier to see. I also taped some white paper as a background for the colored lights.

Marquee white-screen test pattern with prism-like image below

This picture is a blow-up of the prism-like image

Enhanced closeup of the Prism-like image

Has anyone else seen this before?

What is causing it Question

Am I "overdriving" the Marquee in some way?

Thanks for your help

....Wayne

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

Bubbles in the glycol?

Heywood Jablome · Joined: 12 Mar 2006 Posts: 1548

WayneB · Posted: Tue Jun 30, 2009 7:07 pm Post subject:

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

You just need to put a little more glycol in them. The bubbles are at the top of the chamber, rapping on the tubes won't do any good.

WayneB · Posted: Tue Jun 30, 2009 7:19 pm Post subject:

Tom.W · Joined: 09 Mar 2006 Posts: 6635

You might need to add some of this....

http://www.mcmelectronics.com/product/20-4275

Turn down the contrast and brightness for the sake of your eyes and look through the lenses. You should see the source of the relection on one or all CRT tubes.

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

I bet you could put some masking tape or other blocking material over the top of each tube face -- which you're not using anyway -- and keep that stray light from leaking out. Some people say masking the top & bottom "unused" areas with black material will help your contrast ratios.

That works with an AC projector. I don't know if you can do that with an LC. Maybe on the back of the lenses?

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

How high is your brightness?

Heywood Jablome · Joined: 12 Mar 2006 Posts: 1548

jkruger · Joined: 24 Oct 2007 Posts: 2435 Location: Carlsbad, CA

I wouldn't try to mask an LC pj. Black stuff between the lens and c-element might get too hot and make a mess.

stefuel · Posted: Tue Jun 30, 2009 7:55 pm Post subject:

The image inverts when it leaves the lens. Look in while it's running with sunglasses on. You will see one large bubble at the top, inside the coupling of each color you see projected on the wall. You could blank it with some black tape or paper rolled in to match the curve of the c-element. The fluid does not get that hot. I have seen factory installed blanking panels on other LC projectors.

ecrabb · Posted: Tue Jun 30, 2009 8:33 pm Post subject:

Yeah, I probably wouldn't use tape on the lenses, as it would be a mess, but a plastic or perhaps flocking tape stuck to itself to seal the adhesive or something might work.

Some later XG LC's had factory-installed masking panels - I've seen them in pictures. I bet if you searched here or at AVS long enough, you might even find them in a photo. I've thought about making a set for my G70 to try, but it's LOW on the priority list.

SC

WayneB · Posted: Tue Jun 30, 2009 8:51 pm Post subject:

dturco · Posted: Tue Jun 30, 2009 9:07 pm Post subject:

dturco · Posted: Tue Jun 30, 2009 9:22 pm Post subject:

Also a more important question is where did the Glycol go? Are your bellows leaking?

I misread your process, as purpose. Sorry about that. This is what you need for the process

http://www.etechvideo.com/techtip8.htm

Kiev Savoie · Joined: 25 Oct 2007 Posts: 432

Even if you don't have a leak i would imagine that those bubbles are scattering light to other places on the image and may be affecting your black detail a little. the surface of an air bubble suspended in a liquid is usually shiny, even mirrored. it could be like having a tiny disco ball hanging out at the source of your image! At least they aren't spinning! But then again maybe not.

WayneB · Posted: Tue Jun 30, 2009 10:05 pm Post subject:

dturco · Posted: Tue Jun 30, 2009 11:03 pm Post subject:

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I, like Chip, have seen a soft flocking material adhered to the top and bottom of the C-elements. I believe this is done to block any reflections of the image off the screen or any surrounding reflective material to be focused back into the LC chamber and then possibly back out of the lens onto the screen therfore contaminating the original picture. To demonstrate this i bet you could shine a very bright flashlight onto the screen while the PJ is off and then move it around and you will see another light source moving with it. That would be the light being reflected off the screen into the PJ lens then back out. Now this is just a theory but it makes sense to me.

Athanasios