FixYourDLP.com Forums

Hi all. I was curious if this television used a light tunnel. The bottom half of my screen has a black shadow over it.

also, are there removal instructions anywhere on how to remove the light engine?

Hello adezan.
That is correct, your tv dose use a light tunnel, since it uses DLP technology. As for the symptoms you are describing can either be one of two things. The most probable is a collapsed light tunnel. It’s the part of the light engine that is surrounded by mirrors, so its possible on might have falling off due to the heat of the light emitted from the lamp (500 f). the other small possibility is the DMD board that might have a circuit malfunction.
Here is a small reference guide that might be able to give you an idea of what you are up against.
http://www.fixyourdlp.com/forum/viewtop ... =21&t=1289
If you do diced to buy a new part search buy part number & tv model. Some light engines include the DMD board, so check the description.
If you have any questions or doubts let me know.

so i was going off of what my girlfriend was telling me and just got a chance to take a look at it personally. On the bottom half of the screen there are these small white ovals which form to create lots of small white boxes consisting of like 10 of these little white ovals. and they flash as well. Could this be the main chip with the mirrors in it? Its almost like pixelation where the messed up pixels just flash white. and you can see the image through these white dots like the dots are just over them. Its definitely something on the DMD board but what?

Hello again adezan.
I think the DMD board just became our prime suspect. When a picture shows white spots, ovals, lines, or pixilation there is a very high possibility that the DMD is defective, in time the entire picture is going to be covered. The only way to fix the tv is to replace the DMD board, if you look online you’ll notice very few places sell it as an individual item, that because it typically comes include in the light engine. If you do decide to buy one, I suggest you look by part number & tv model, compare pictures of the actual product with the one you are going to replace, so you buy the correct one.
Good luck.

now would it be possible if i found a dmd from the 56 inch version of my tv and take out the DLP chips and the chip with the mirrors in it and just swap them with the components on my board? or does it seem like it is a component other than the chips?

also on those tvs there was a 56mx195, 56hm195, 62mx195, 62hm195, 72mx195, 72hm195. I was looking on pac parts and they all use the same parts other than the light engine. The light engine is the only thing with the different part number. Is it possible that everything is the same with these except for the last item in the light engine which projects the image onto the screen? Could it be that the projector after the dmd board just increases or decreases the size? meaning that all the parts on the dmd boards are the same between all these models?

Hello adezan.
I wouldn’t recommend you do that, in my personal experience I’ve installed a entire light engine from a Samsung 52” to a 61” tv and on the top part of the picture there was a black bar, making me realize that it was too small. If you try to swap just the DMD board and using the same light engine, there is a very high probability that the tv wont even turn on since the dmd uses different parameters to control the light engine that projects the picture on the screen. Try searching for the DMD (there are rarely sold individually, but good luck) by part number & model number in various websites, if all fails your going to have to buy a new light engine with a DMD board. For more info read this post:
http://www.fixyourdlp.com/forum/viewtop ... f=4&t=1315

One last thing, there is no such thing as a chip with the mirrors, maybe you got it confused with the light tunnel, here is what it probably looks like.
Yes you could swap it since most models share the same one, but that’s in case one of the mirrors has fallen of.
Good luck.

oh. lol. i was reading somewhere that the dmd chip had like 3 million little mirrors on it. With that light engine you took from a smaller tv, was the only thing wrong that you had was that the picture was smaller?

Hello again adezan.
That is correct, the small picture was the only thing wrong, how ever remember that it was the entire light engine swap, not just the dmd.
How ever I don’t know if on the long wrong, something goes wrong.

BTW, you we're correct about a chip with tiny mirrors here's a portion of Texas Instruments site about DLP. If you like tech stuff it's pretty interesting.

1. The semiconductor that continues to reinvent projection

At the heart of every DLP® projection system is an optical semiconductor known as the DLP® chip, which was invented by Dr. Larry Hornbeck of Texas Instruments in 1987.

The DLP chip is perhaps the world's most sophisticated light switch. It contains a rectangular array of up to 2 million hinge-mounted microscopic mirrors; each of these micromirrors measures less than one-fifth the width of a human hair.

When a DLP chip is coordinated with a digital video or graphic signal, a light source, and a projection lens, its mirrors can reflect a digital image onto a screen or other surface. The DLP chip combined with the advanced electronics that surround it produce stunning images and video that have redefined picture quality.