Bright spots on one side with Benq W1070

[Shivam]

I have recently noticed a white circular spot on lower right side with an incomplete circular spot near it. (The screen itself is clean)

I noticed them while watching a movie with titles on a dark screen. I got concerned and checked without any signal being fed to the projector and also with the 'eco blank' on. The spots are visible in both the cases. They are not present when displaying any colored image but are visible only on black.

Can someone explain what these circles/spots might be? Should I be worried?

I am attaching a picture taken on phone showing the spots. Since the spots show only on black display, I had to enhance using an image editer to show the spots.

 

[Shivam]

The spots are visible only in dark / black scenes. In bright scenes the spots disappear.

 

[rajudhs]

These are dust particles. (just 2 tiny dust particles inside the lenses, basically in the path after color wheel until upto the final lense )


Only way is to disassemble it and clean the optics area, yourself, by referring service manual here

Benq W 1070 Service Manual
or
https://docs.google.com/folderview?id=0B_xTFybwtlbvU1oxdHRNcWd3LTQ

What you need
- All the tools to open up the above
- Some Guts
- a clean room, where more dust wont creep in, when you open

- air blowing can (most effective)

Foooit AIR Duster Dust Remover IN India Compressed AIR CAN MRP 450 | eBay

or

blower brush you get for camera cleaning

Camera AND Lens Cleaning Soft Brush AN Blower Dust Cleaner Best Quality FOR DSLR | eBay

I did this on my old Optoma Projector once.

Alternative is to goto service centre and ask them to do it.

Cons
- Service centre guys will try to rip you off, saying DMD chip is gone and need replacement and charge you 15K or 20K
- if they agree with honesty its dust particle and they can clean with just labour charges and service charge, you can give to them.
- no parts need to be replaced only cleaning.

at least in my case Optoma service centre in bangalore was not agreeing and kept on saying DMD chip is gone and 15 to 20K to replace.

Told them to shove up their behind and did it myself.

 

[Shivam]

These are dust particles. (just 2 tiny dust particles inside the lenses, basically in the path after color wheel until upto the final lense )

Thanks for the detailed information and links. The spots are lighter in color than the remaining of the display. I had expected the dust to throw dark spots on the display and not bright spots.

 

[rajudhs]

"I had expected the dust to throw dark spots on the display and not bright spots" This thinking is what may be making service centre guys to mint money

its exactly the opposite

1: Dark Spots (Pitch Black)
- this is due to DMD chip
- the pixels will stop functioning and each pixel will be a dark tiny and small black spot
(as the mirror which represents a pixed is dead on DMD chip and results in that pixel DEAD . i.e BLACK in colour, similar to dead pixels on LCD TV monitors)

2: big, fuzzy blobs like above

- 1 dust particle in the path of projector image display path, is magnified 100 times due to optics and appears as one big blob, like your case.


you can do a you tube search for projector dust blobs and you will see similar images reported by many people.