[selim]

Actually there are three of them in different parts of the screen but only one of them is big enough to notice and I can only notice it when there is a big white or light colored area around it (I used Windows paintbrush program to display the whole screen in white)


I am not even sure if it is a bad pixel since I thought DLP technology wasn't supposed to have this problem. The black spot is about a pixel in size but it has kind of a small tail on top of it. It is near the lower left corner. Can it be dust on the screen? I can't be certain whether the set already had it or it happened over time.


Do you think I shold call a tech rep or shall I try to ignore it? My LCD flat panel monitor also has a bad pixel but I hardly notice it during daily use.


-Selim

 

[Tom Roper]

Selim, because a pixel, if stuck *on* would be white, and stuck *off*, would be black, you should use the paintbrush program to cover the suspected area with a neutral gray. If it displays white, or black either, it will be revealed. And it would have to be ONLY white, or black, not blue, not green etc.


Dust on the screen could possibly masquerade as a stuck pixel, since the image is a projected one, from a lens. If the dust was on the lens itself, you would not see it on the screen. If dust was on the DMD, it would have to be about one/millionth of an inch small to only cover 1 pixel, and adhere to the mirror against the high frequency motion of the mirror tending to throw it off. Most likely instead, a dust speck there would show up rather huge on the screen, under the microscope so to speak. But a debris speck on the inside of the screen would be displayed actual size.


Tom

 

[selim]

Tom thanks for the explanation. I did cover it with a gray rectangle in paintbrush and it still displays as black. Since it is a very small but not a uniform sized spot, do you agree that it is possibly dust behind the screen?


I wish it was as easy as opening the front of the set and cleaning the back of the screen with a soft clothe. I know it may not seem like it is worth calling a service technician over such a small problem but now I am bothered by it even if I don't usually see it from where I am sitting (It is very easy to notice it if I am near the set though).


Also I am now suspecting that the screen area may not necessarily be dust proof so what if there is further dust accumulation later on?


-Selim

 

[selim]

After careful examination I discovered five more black spots and one that looks like a short strand of hair so looks like it is definitely dust. Also there is an area on the screen that is the size and shape of a fingernail that is a different tone of gray than the rest of the screen.


-Selim

 

[Tom Roper]

It actually IS as easy as opening the front of the set, and cleaning the back of the screen. Have you ordered the service manual yet? There is a diagram that shows how to remove the screen. The pieces on the sides have to be removed, but I don't have the manual with me until late tomorrow. You can also clean the lens, focus it. Maybe someone can post the procedure, or I will as soon as I get the manual back, late tomorrow or early Tuesday.


Tom

 

[selim]

Thanks Tom! I was joking when I talked about opening the front of the set but I am glad this set is more user servicable than I thought. I will order the service manual but in the mean time I appreciate any tips you can provide.


-Selim

 

[Tom Roper]

Selim, I wish I had a scanner, but...here's my best attempt to describe:


1.) Remove the upper 8 screws along the top and sides, from the back.

2.) After removing the screws, pull the bottom and side holder part of the cabinet backwards.

3.) Remove the 4 screws behind the speaker grill, above the speakers.

4.) Remove the supporter.

5.) Loosen the screws and remove the front mask.

6.) Done!

 

[Rbuchina]

Selim,


My 437 arrived yesterday. While I was waiting for it to warm up (It was 22 deg F outside) I wanted to take a look at the lamp and how to change it. I saw a small panel above the input connections and opened it thinking it was the lamp. Well it turned out to be a 3X5 inch access hole that you could view the entire inside of the screen. You could even see the top of the final lens in the unit. This may be easier than opening the case if you still want to inspect the screen.


The lamp in on the opposite side and it changes rather easily.


Ray

 

[selim]

Tom and Ray, thanks for the instructions and tips. I think I'll hold off on opening the set for now since I can hardly see the dust from where I am sitting and I am a little bit afraid to introduce new problems to an otherwise perfectly working TV. I still plan to order the service manual since I may need it in the future.


-Selim