First of all I'm no expert. I don't know anything about the inside of projectors, this is the only projector I've opened up. I figured I would write this up... It might help someone, however it might also ruin someones projector, just read it and make up your own mind if it's something you want to try. I don't stand behind it, it's not official, it's just what I did as a beginner and it fixed my dust blob problems.
So yeah I got a dust blob.... I didn't have warranty or anything else so I pulled my HD65 apart. It's invasive enough that if you do have a warranty, I would suggest using it. However it really wasn't difficult, I would consider it low risk...
Basically I followed the first step of this guide.http://www.avsforum.com/avs-vb/showthread.php?t=1242314
Once you get the top off, don't bother disconnecting any cables like I did. Just slide the lid back.
Then you can take the grey ring off the lens where you focus, with 3 small screws.
Then you can take off a small bracket that guides the metal piece that adjusts the zoom with 2 screws.
Then you can take out the lens with 3 small screws and you have access to inside the chamber. Be very careful with both ends of the lens.
It was surprisingly simple to clear the dust out, even though I did use compressed air...which I'm sure most people would shudder at the thought of doing that. I figured it's supposed to be sealed... if you send air in it's only going to come out the same way. I cleared any obvious dust out of the way that would kick up with a q-tip, making sure I didn't touch any of the mirrors etc. Worked very well for me, however if you have a vacuum attachment or a better way feel free to try it out.
The first blast of air got rid of my original blobs. I put the lens back in with 3 screws which seals the chamber again, turned it on to test and there was another blob in a new place. One more blast of air and everything was cleared and it looked 100% again.
Put it back together as easily as it came apart and I was done in about 20mins. Been using it for a few days problem free... I hate dust blobs so it was worth it to me... but again please make up your own mind if this is something your comfortable with, I don't technically know what I'm doing!!!!