Mitsubishi DLP WD-73640 No Color Red

[BigJerm760]

I replaced the lamp in my Mitsubishi DLP TV Model number WD-73640 and after turning the unit on it seemed fine except after about two minutes the color red is not present in the picture.
Everything else seems OK except the loss of the color red. Is this a color wheel going bad or something else? I did remove the optical block to clean old debris and dust out. This seemed to help a little, meaning after I put it back together it fired right up and Lasted about ten minutes prior to losing the color red? Looking for help on Troubleshooting my missing red! Help please.

 

[Hi-Fi Man]

The DLP chip could be failing or as you said the color wheel. My bets are on the color wheel though.

EDIT: could also be the light engine..

 

[BigJerm760]

With Light engine or DLP chip would you see more artifact in picture or more severe symptoms than just a loss of one color?

 

[Aikouka]

Out of curiosity, why do you think the color red is gone? I'm surprised that it would take a few minutes to notice it since red is such a prominent color for mixing. I'm wondering if it may not be hardware at all. Have you checked the color settings on the TV? Perhaps a reset of the TV's settings couldn't hurt to see if something is just out of whack.

The reason why I ask is that the color wheel shouldn't just randomly go bad with a single color after you replace the lamp. Color wheels are kind of like Viewmaster slides. They have segments that are shaded in a specific color (and other types to improve picture quality) which pass over the reflected light when that color should be displayed. It just seems strange that your red segment would break during the short time that it takes to replace your bulb. That's also weird because I don't normally hear about losing a single color because of the color wheel, but the usual problem is that the color wheel shatters.

With Light engine or DLP chip would you see more artifact in picture or more severe symptoms than just a loss of one color?

Failure in the DLP chip would normally result in black or white dots. The prior means that the mirror is stuck in a closed state and the latter means that the mirror is stuck in an open state.

 

[slag]

color wheel.. Smack the side a bit.

Not the dlp chip and not the light engine.

There's really only 3 parts. The color wheel, the light engine, and dlp chip. Failure of the dlp chip will result in a starry night picture as the other poster described above as the tiny mirrors fail to work properly. Failure of the light engine will result in the TV not showing a picture as if the bulb or ballast has gone out. Failure of the color wheel is about the only thing that will cause the red image aside from a poorly set up color menu in the TV.

 

[BigJerm760]

Thanks for all the input.. I am ordering new color wheel now. The Loss of the color red occurs only after about 90 sec or so. The TV fires up just fine and picture looks normal with all colors and then poof only greens whites and yellows are present in the picture and there is like a strobing affect. Even the Mitsubishi Logo wich normally appears red with the three diamonds is in green and not red. I don't think it's the settings because I do have about 90 secs of normal function and then no red.

@ Slag: When you say to "smack the side a bit" you meen the actual color wheel, right? I did take the whole thing apart before ordering a new color wheel to see if dust or debris was impeading the movement of the wheel and to check if it was intact/not broken. It looked fine and after cleaning it out it was a little better. I watched a video regarding color wheels and the most common problem seemed to be the bearings in the wheels going bad and not spinning at the appropriate synced speed. I hope thats what is taking away my red thank you everyone again for all the input and attention. Cheers!

 

[BarkingGhostar]

I find it hard to believe that the color wheel is being targeted for the loss of red. Its a freaking wheel that spins up to a near fixed RPM and it is the job of the DLP engine to either use of toss the red light during the red-segments presence (in front of the lamp/light source).

To me, whatever tells the DMD to 'use' while red segment is in alignment with the light source no longer is. If that controller is on the DMD itself then a new color wheel isn't going to fix the DMD issue.

 

[BarkingGhostar]

BTW, I should clarify that the 'use' or 'toss' is when individual mirrors (that create the image of a pixel) are tilted in one position or another. They tilt one way to allow light to travel down the optical engine, lens assy and onto your screen, or tilt the other way which is out of the optical path.

The color wheel always generates red, green and blue light no matter what, but can only do so one color at a time. During the r, g and b temporal segments only those pixels needing that individual color are decided upon by the video processor telling the controller to either send that color via mirror tilt position, or to not.

 

[BigJerm760]

If it is not the color wheel then how would I begin to check the DMD use or toss function? Have you ever encountered this before? What you say makes sence and I dont want to waste 140.00$ on a color wheel if I don't need to replace it. I am new at this and am really over my head when it comes to fixing a DLP television.

 

[sdifox]

Hookup a computer to your tv and display test patterns.