So yes... sure... vacuum and blow air... sure... as if!!!
Joking of course :P It's just that I wasn't that lucky and I worked on this for hours instead of minutes, so if anyone has the same problems I had, I figured I'd make my own tutorial for the unlucky ones
If you see dust blobs on the screen, this is unlikely to be about the lenses, it will more likely be related with the "DMD" module.
The only way to access that is as follows:
1) Unscrew 5 "+" shaped screws from the bottom
2) Unscrew 1 "-" shaped screw from the left side (watching the projector with the lamp facing you)
3) Remove plastic bit that covers about 1/4 of the top: it is now possible after you removed the screw in 2)
4) Unscrew 1 "+" shaped screw from the center of the top surface of the projector
5) Remove the pastic top (help yourself with a flat screwdriver if needed to pull the edges)
6) Remove the dark "+" shaped screw in the picture below next to the lens unit to access a small window to the DMD
https :// ibb.co / dzJCRK - Position where the screw was
https :// ibb.co /bTFFfe - Window opened after removing the screw
(sorry for scrambled urls, but I dan't post images as I am too new to the forum)
There's no point going any further as for what I understand even if you were to completely remove the optics, that window would still be your only way in to access the dmd.
After opening the window, I blew some compressed air (MISTAKE!), but that stained the surface, so I then had to clean, the best medium proved to be a cotton bud, but that leaves tiny hair bits that are hard to remove too, even when blowing air or vacuuming (I used an air pump for both tasks)… the hair bits keep moving around, but you never completely get rid of them. After HOURS… like 4 hours or more of trial and error, I ended up proceeding as follows, which is a bit unortodox, but ir worked:
1) Leaving the window open, put the 1/4 top cover back in place, this will push a rectangular button down and this will allow you to turn on the unit. You will need to put some weight on the cover so that it actually pushes down the button.
2) Turn on the unit, if necessary go into menu and change the background colour to black
3) Make the screen as small as possible, then play with the focus so that your hair is in focus (the writings and edges of the screen will be out of focus now)
4) Stick a cotton bud and a thin air pump (deflate side = vacuum) into the window and clean the surface until no hair is left, or not enough to be visible when the image is in focus
a. The dust in my case was on the little glass-like surface that in the pictures above would sit slightly to the right of the window, towards the top, so you would need to insert the cotton bud towards top-right direction in that picture
b. When you see the cotton bud going in focus, you are hitting the right spot
you will notice the cotton bud is nearly the size of the dmd itself, so it will take a bit of precision but not much time at all
c. You will notice that up on the dmd is down on the screen, and left on the dmd is right on the screen (this holds true if you are s projecting an image in a wall in front of you and in upright position, not sure if you choose other settings)
d. Doesn't take a lot of pressure at all, if you put too much pressure in my experience you will leave small marks on the dmd, which can be cleaned but will take more time
e. Change the cottonbud often, after a few seconds of usage they start loosing more hair, making your job harder… remember that your projector is worth 100's of $£€, a cotton buds box only about 1 $£€ :P
f. To play safe, when you extract your cotton bud make sure it's not too hot, in my experience it never was, but remember you have a very hot lamp nearby, so it could and last thing you want is for it to melt/burn inside the window
Hope this helps!!