How does one clean a digital projector? Small pink blemish on screen...
January 20, 2016 2:28 PM   Subscribe

A small pink spot appears on the same area of the screen when using a Canon digital projector. What is the cause and how does one go about cleaning/fixing this?

Could it be a hot spot on the bulb itself, requiring it to be replaced? Maybe something to do with the CCD, or another area within the internal optics? I want to explore all DIY options, but I am also understand, as the final resort, the need to take it in to be serviced. A team of us opened up the device for a cursory inspection and cleaning, but I appreciate all knowledge and advice for cleaning. The goal is to remove the tiny pink blemish that appears on the screen, but any information that best describes how to maintain a digital projector is ideal. Thank you for your time and consideration.
posted by captainsohler to Technology (9 answers total)
 
Can you show a picture of the blemish? Is there a test/calibration screen you can access that lights up just the red, green, and blue pixels?

Or, perhaps, make a slide deck with three pages: one all pure red, one pure blue, and one pure green? Is the blemish visible on each of those pages?
posted by JoeZydeco at 2:45 PM on January 20, 2016 [1 favorite]


Check the outer lens for an oil smudge. Replace the bulb. Anything beyond that and you will want to have it serviced by a professional or you may void your warranty.
posted by Roger Dodger at 2:46 PM on January 20, 2016


Response by poster: Rodger Dodger: we are willing to go beyond that.
posted by captainsohler at 3:03 PM on January 20, 2016


Response by poster: JoeZydeco: Because the the projector is not at my location, I cannot furnish a picture. I can tell you that it appears very small on the projector screen, and that it is always in the same place. To call it a blemish, is just that: it is a small, irregular spot on the screen.
posted by captainsohler at 3:06 PM on January 20, 2016


If the spot is specifically a pink spot, I would suspect that there is something wrong with the green pixels or green color filters where the blemish is found, depending on the exact technology your projector uses. It is unlikely to be something a layperson can easily fix.
posted by Aleyn at 3:19 PM on January 20, 2016 [5 favorites]


Once upon a time, I ended up with 3 old Proxima LCD projectors which had blemishes on the projected images, which as best I can figure was caused by the users turning them off without letting them cool down first. Make sure your users are turning off the projector with the power button and not just pulling the plug. After the light goes out, the fan should run for a few seconds to a minute; only after the fan shuts off is it safe to unplug.

If this is the case with your projector, it's probably done permanent damage to an LCD module. The projectors I had had separate red, blue, and green LCD modules, and between the 3 projectors I managed to find one of each color which was undamaged so I could get one projector properly working. Those modules were replaceable without digging too far into the projector, which is good because you don't want to mess with the rest of the optics if you can help it, their alignment is critical.

What's the exact model of the projector?
posted by MoTLD at 4:05 PM on January 20, 2016 [1 favorite]


There was an oddly similar question earlier this month:
What's that faint red glow on the movie theater screen?!?

. . . I attended a showing of Star Wars The Force Awakens recently at a small-chain theater and was shocked to see a faint red glow in the center of the screen. While it was there during the entire movie, it was most noticable during the dark scenes . I approached the manager who first complimented me on being the first person to ever notice the glow, then he tells me that it's a byproduct of their digital projectors and that all of their auditoriums have it. . . .
posted by jamjam at 4:11 PM on January 20, 2016


Response by poster: MoTLD: The model # is SX80 Mark II
posted by captainsohler at 5:55 PM on January 20, 2016


Best answer: Well, I was able to find very little about this projector, but apparently someone else is having the same problem with a similar model here: "The Canon Realis SX50 service manual does not seem to exist on the net. Trying to clean out "dust blobs" that create pink spots on the screen. Apparently, it is very difficult to take apart (and put back together), with "pros" needing 4+hours to do it. Canon won't even hazard a guess nor give an estimate for cleaning the projector. Ugh."

If you're handy with taking things apart and putting them back together successfully, you might try it yourself, in which case my advice would be not to take out any screws that seem to hold lenses or mirrors in place and don't touch any lenses or especially mirrors with anything except compressed air. If you're not handy with such things, only do this if you're willing to sacrifice this projector as a learning experience.

I was unable to come up with any free repair manuals or parts breakdowns, nor any manuals at all specifically for the mark II, but I did find service manuals for the SX80 here and here for $9.95 and $12.99, respectively. I have never used either site before so I can't vouch for them.

Finally, there is an air filter behind a panel underneath the projector which should be cleaned or replaced frequently to prevent overheating. If you aren't going to dismantle the unit, I'd try taking out that air filter and carefully applying the most powerful vacuum you can get your hands on to the air intake under the filter, as well as any and every vent on the unit. You might get lucky and dislodge whatever speck of dust is causing the problem, if that's all it is.

Best of luck!
posted by MoTLD at 7:54 PM on January 21, 2016


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