Question about InFocus ScreenPlay 4805 Multimedia Projector

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Light tunnel where is the light tunnel

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  • busta25 Dec 29, 2007

    tr;yinjg to find the mirrors for gluing because I have a shadow

  • busta25 Dec 29, 2007


  • tocarpen Jan 02, 2008

    how do you get to the light tunnel. directions would be great. thanks



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Anyone can tell me how to reset lamp to 0 hr. screenplay 4800 projector ?
I tried already but still reset factory default.

Posted on Jun 21, 2008


OK, this is the easiest way leaving all the cables plugged in otherwise you would have to remove the power supply and lamp/fan housings. Here goes and good luck. Keep every set of screws labeled so you won't mix them up. You may find the job easier if you remove the lamp and aluminium plate between the lamp housing and color wheel. The lamp has to be removed first!

1. Remove the aluminium cover behind the lens(3 screws).

2. Remove the small board on the color wheel (1 small screw).

3. Unscrew the screws(2) that secure the color wheel. Carefully lift the color wheel by its bracket. Notice that this would be still be attached by it's ribbon cable. Pass a piece of thin wire through one of the screw holes on the color wheel and tie it out of the way. I usually tie the other end of the wire with the DMD heat sink.

4.Looking under where the color wheel was you would see a metal clip (2 screws) holding the light tunnel. The most delicate part is the color wheel so be very careful as this easily breaks.

Posted on Jan 05, 2008

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How do you get to the light tunnel. I have opened the unit and I see the color wheel.
I do I get to it from there.

Posted on Jan 02, 2008

Hi Busta25 I have answered your original question. If you intend to go ahead, I will guide you step by step.

Posted on Dec 30, 2007

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Thank you for your email inquiry. It appears you are looking for the light tunnel for a projector? My intial question to you is why are you seeking the light tunnel to your projector? also, which model is it?


Posted on Dec 28, 2007

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Posted on Jan 02, 2017

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1 Answer

RCA Light Tunnel

I have one for sale 75.00 2705898074

Nov 18, 2012 | RCA HDLP50W151 50" Rear Projection HDTV


Rear projection TV displays a shadow on one corner or side of the screen.


This tip may be helpful only if your rear projection TV is displaying a darker shadow on one portion of the screen. If the shadow shape and size will not vary, that means that there is probably a detached mirror in the device called Light Tunnel, located inside your TV.

Most rear projection TV works projecting the light from the internal lamp on the screen. Before reaching the screen , the light will pass through a 'pipe' whose internal surface is covered in rectangular mirrors, located all over the tunnel surface.

A quite common fault is caused by one of the mirror detaching from the the light tunnel internal surface , and falling down or hanging in there. This will be seen on the display as a darker shade located near to one side of the screen.

The light tunnel is located in the light engine. To repair the problem the TV must be disassembled by a technician. Accessing and disassembling the light engine is not a repair that can be done by the owner.

Click here to view pictures of a light engine for a Samsung rear projection model. The tunnel is the optical device located in the light engine.

If you are a technician, to replace the light tunnel you will have to take apart the light engine, that apart of being quite a sensitive optical device, is also the most expensive part on a rear projection TV.

In that case you may find useful the service bulletin posted below, that is illustrating how to replace the light tunnel on a light engine for Samsung rear projection TV. Please be aware, that if you attempt doing this operation without sufficient knowledge and experience, you may damage your TV set beyond repair, as the light engine is very expensive.

How to replace light tunnel on a Samsung rear projection:SERVICE BULLETIN

The file is on PDF format.



on Feb 05, 2010 | Samsung HL-P5063W 50" Rear Projection HDTV


Mirror or light tunnel collapsing

A weakness that you might experience with your projector is the collapsing of the light or mirror tunnel. Not sure if this is common to DLP projectors only. The symptom is that you see grey bands or shadows on the edge of the TV image - this is caused by a mirror getting in the way of the bulb light. The glue holding the mirrors together seems to weaken over time (3000 lamp hours in my case) and causes one or more of the mirrors to loose its position. For solution, search for "mirror tunnel" or "light tunnel" under all projectors. The problem seems to be quite widespread. I managed to fix my LG's.

I wonder why the manufacturers don't use a rectangular glass tube that is mirror plated on the long sides ?!?! Suppose they want to sell new projectors after lamp or mirror tunnel expiry!

on Sep 15, 2008 | LG RD-JT91 Multimedia Projector

1 Answer

Dark haze left side of screen about 4 to 6 inches wide only in the wider screens not in the native

Its a Light Tunnel failure. Go to and search for 4805 Light Tunnel. There are instructions to open the PJ and repair the Tunnel. Also, I posted a DIY replacement option in lieu of fixing the very fragile tunnel.

Jan 02, 2011 | InFocus ScreenPlay 4805 Multimedia...

2 Answers

The upper left corner of the screen (triangular shape, approx. 8" vert. and hor. from the corner) is showing dimness, not completely dark but maybe halfway. What might be causing this? Thanks.

This is your mirror tunnel. Light passes through the mirror tunnel to the DLP. The tunnel is made up of 4 mirrors glued together. Over time the glue comes apart and the tunnel shifts.

It starts out like this: |_|
and when the glue breaks down it does this: \_\

So the light, instead of passing through the mirror tube, goes through the ends of the mirror, so you get SOME light but not all.

I contacted RCA and they said:
"Ok, well sadly they do not offer the light tunnel anymore, which is what you need. Sadly you would be rendered to get a whole new light engine assembly. That would be the D.N.D module, light tunnel,color wheel,optic spanner, and oci. mirror. Your best bet would be to search ebay for a broken engine and replace it that ways. "
Awesome support! NOT! (That is the actual full text of the message from RCA support.)

I have some high temp epoxy and will be attempting to re-glue the parts myself.

Mar 06, 2010 | RCA HDLP50W151 50" Rear Projection HDTV

1 Answer

New Problem after fixing Light Tunnel on a SP 4805

It sounds like you have mounted the replacement light tunnel incorrectly. It is a common error. What has happened is you have the light tunnel sitting on yop of the positioning stop which is opposite from the color wheel side. If you take it back apart you will see that it's not laying parallel to the casting. if you reposition it so it is just touching where the opening is in the clamp on the color wheel side you will feel it fall into place.

Jan 22, 2009 | InFocus ScreenPlay 4805 Multimedia...

1 Answer

Dark edge of screen

there is a part inside the engine(the part that produces the picture) that is a mirror tunnel. The actual part name is "light tunnel" this tunnel takes the light from the bulb and compresses it into a smaller beam of light that is then shined onto the DMD(million mirrors) this produces the picture on a DLP TV. this mirror tunnel is glued together on all edges. One edge of your "light tunnel" has started to come unglued and has slipped a little. This causes the slightly dark area usually on the left side of the picture that you see. the light tunnel can be replaced as a single part. much cheaper than replacing the whole engine.

Jun 19, 2008 | Samsung DLP HL-P5663W 56" TV

4 Answers

Infocus sp4805

Hi Gerry

You will have to be more specific

Apr 01, 2008 | InFocus ScreenPlay 4805 Multimedia...

3 Answers

How much does a light tunnel repair cost?

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.

Mar 25, 2008 | InFocus ScreenPlay 4805 Multimedia...

1 Answer

Infocus X3 light tunnel

Are you speaking of the small prism shaped tunnel or the lamp itself? The prism or light tunnel may be accessed underneath the metal bracket that holds the color wheel in place. Be extremely careful as even breathing on this may cause it to collapse (ok, I exaggerate).

Feb 07, 2008 | InFocus X1 Multimedia Projector

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