white dots on projected image

[rajudhs]

I see white dots on the projected image, from Optoma GT720 projector.

Its working fine otherwise, and these are visible only on black/dark image.

while playing a movie, you cannot notice it, even though they are there. except in totally dark scenes

This seems to have happened, while moving the projector, there was quite an amount of dust inside, so when i moved this projector un-mounting dust seems to have moved around.

Picture was flickering as well initially, i opened the projector and blew air using air can to resolve this color wheel flickering due to dust.

That solved it. but these white dots still remain.

Anyone faced this issue? any clues and solutions?

high res images below to give an idea

https://picasaweb.google.com/111615087159925481338/Projector?authuser=0&feat=directlink

Its old, so out of warranty

For me, it looks like, some dust or residue stuck in the light path of the projector

 

[manoj.p]

these could be dust blobs either on color wheel or lens. Since there are few outside screen areas, there is a chance those are on the lens. Clean the lens with a streakfree solution in circular motion. Usually the glass cleaning cloth and cleaner works good on projector lens too.

if on color wheel or inside of lens, then only cleaning from inside is the option.

 

[Moviela]

The dots are out of focus, and I assume they are constant. This would rxclude the color wheel as dirt there appears in colour, and the imager having dust would be in focus. This leaves the reflector (though this is often within the lamp, so no chance of dust there.) Some units have condensing lenses that might have dust, but not likely visible on the screen. You might have dust on the lens, or even worse fungus inside the lens. If fungus is rooted in the glass surface you will unlikely be able to remove it. Acids and solvents to remove it will also remove the antireflective coating as well as the antiprismatic coating resulting in colour fringing.

 

[rajudhs]

I got my white spots above fixed my self, the dust is the root cause.

But beware of optoma bangalore - service centre "digicomp"

 

[rajudhs]

Beware of optoma bangalore - service centre "digicomp" V.V Puram

Day 1 - gave my projector, the smart lady at the counter, says DMD chip is BAD
- i said,its dust as the spots move and pixels are fine
- they agreed to investigate

Day 3 - got a call, that its fixed, its indeed dust problem, they are running some diagnostics after fixing and i can come and collect

Day 4 - i goto to collect it, they say, diagnostics failed, its DMD issue and need to change it.

I said, can you show it to me.

They showed it to me, and i dont see the earlier white dots.
what is see is a new problem, the image is fuzzy, some scuff marks on the image.

- I told them that i dont see the original issue, and this scuff marks are not DMD issue.
the engineer must have left traces of his dirty hands on lenses, asked them to open infront of me and clean it.

- They opened and started cleaning. The pathetic engineer, started cleaning it with a cloth that looks like strains of thread (typically used by carpenters to apply wood polish )

- got furious, asked him to clean with a cloth that comes with spectacles etc.

- they dont even have such a cloth, started cleaning with handkerchief

- I thought what the hell, but waited just to see how to dismantle a optoma projector

- at the end, i knew how to completely dismantle the projector. including the lenses.

- acted innocent, said thank you. i said i will buy DMD, send me a quote and left.

they didnt bother to send me a quote, but just said, it will cost as much as a new projector.


- I went home, opened the projector piece by piece, cleaned it up thoroughly and issue is resolved, working fine since 2 months.

- The scuff marks were beacuse of service engineer dirtying the GLASS on top of DMD Chip.

Moral of the story
- Digicomp was all set to rip my money.
- how can optoma choose such a vendor, i think i need to escalate and bring to their notice.
- Either Digicomp is highly incompetent or too smart at cheating innocent customers.

so think twice before you approach them.

 

[m.a.sara]

@rajudhs - glad to hear that its working now!

 

[adrenal321]

i have the same problem. although it looks like theres a million of them. Can you please explain in detail what to clean. Is it the lense, dmd chip, color wheel etc. Thanks Edgar

 

[Saket]

The problem indeed looks like dust on the lens to me! These dots look very similar to those pictured by a digital camera, when there are particles flying around or the lens of the camera is dirty.

Lets hope for the best & let the OP try to clean the lens thoroughly by some lens cleaning solution and report back. Please DO NOT use any other solvents as they can be harsh and can damage the lens permanently.

Regards.

 

[Santy]

i have the same problem. although it looks like theres a million of them. Can you please explain in detail what to clean. Is it the lense, dmd chip, color wheel etc. Thanks Edgar

Please change the HDMI cable first and try to isolate it from power cables if any.