Light tunnel alignment - Mitsubishi WD-57734 57" HDTV

the light tunnel under the colorwheel has collasped or the projector has been jarred, knocking the mirror inside of the lens assy. out of alignment. Either way, it will have to be repaired by a technician.

The light tunnel inside the "engine" is either out of alignment or the glue holding the tunnel together is coming unglued and 1 of the 4 sides has fallen in. There are 2 screws to adjust this if the tunnel is still intact. One or both screws can be accessed by opening the lamp door and then you have to remove a thin sticky cover. You will see 2 small screws that will have to be adjusted with a small torx (3) or allen. You will have to have the safety switch pushed in with something and adjust while the projector is on, using the most easily accessible screw, turn it towards the direction of the "banding". It should decrease. If not, turn the screw the other way. The screw that is not so easy to get to is for adjusting the banding the can appear across the top or bottom of the screen. If the banding gets worse or even starts to show diagonally across the screen, it is a good bet that the tunnel has collasped.

Double check that you did not over look any plug connections or ribbon connections when reinstalling light Engine

i am having the same problem and most people are telling me its a light tunnel problem with it being out of align. im still looking into how to fix that hope this might have atleast narrowed the problems down.

the light tunnel is the black tube like thing thats right beside the color wheel. about 2cm long and it has lenses inside of it.

Hi there

The light tunnel is not a expensive part to have replaced and it is better to do it than to keep on buying new lamps.

You can easily find your nearest Authorised Service Dept online.

Tip : Don't let just any monkey do this type of work on your unit , rather pay a bit more with the authorised agents.

Often a piece of foam, debris or such can get in between the lamp and color wheel which can cause the symptom your describeing.

Yes, you are describing a light tunnel failure and it can be repaired. The parts are available, I just don't have any on hand right now. I will be ordering more this week. The part is about $40.00 plus shipping. The repairs can be challenging if you are not experienced. The color wheel has to be removed to get to the light tunnel The light tunnel is very fragile and easily broken.

Replacing the "light engine" fixed the problem. The technician said that there was a felt-like lining in the light engine to prevent undesirable reflections from the insides of the light-engine hardware, and that it becomes detached and blocks an edge of the picture.

We had a dark line along the right-hand side that was like looking at that portion of the picture through a 1" strip of very dark glass.

Because the DLP is new technology, we purchased an extended warranty from Best Buy (actually, their Magnolia subsidiary) which covered it.

The new light engine was slightly different physically, and the technician had a hard time getting the picture centered and aligned on the screen after installing the new one. In fact, he gave up on the first one and fetched a second one from his truck. He also had problems with the second one, but finally got everything aligned.

Sounds like it could be the mirror tunnel. There is a very small mirror tunnel behind the color wheel (looks like a long prism) that can often fail as it is very fragile. This tunnel concentrates and channels the light to the DLP chip and if it collapses it can cause the very issue you describe.

This is a problem we are seeing quite a few. The problem is, you have a defective Lite-Tunnel. This can be repaired two ways. (1) The Cheap way. Replacing the Lite-Tunnel. This is somewhat complicated. You must take the engine apart to change the tunnel. After changing the Lite-tunnel it must be aligned. (2) The expensive way. Changing the complete Lite engine. This is less complicated, but cost a lot more. Lite engine Part Number BP96-00822J . Average cost $1300

Best regards
CircuitCity