Has anyone done this procedure and experienced a poorly aligned image once done? I have an '08 WD-73736. Not long after getting it, I started getting a few of the "blobs" that others have experienced: faint light-colored orbs on black backgrounds, that were presumably dust specs somewhere internally. Although I had seen this thread, it didn't bother me enough to motivate me to tear the set apart. After 3.5 years and nearly 5000 hrs on the lamp... I had to tear my entire system apart anyway to swap out my AVR, I figured it was time to put a fresh bulb in, so I figured it was time to clean out the light path. Although I hadn't noticed the orbs in a long time, I think because there was enough dust at this point that a few orbs just became so many that they weren't as noticeable.
I took the light engine out, and took the lens assembly off the light engine. The front lens (the large one that is exposed inside of the set) had a fair amount of dust on it, but the internal one that is "sealed" inside the light engine was clean. I didn't have the haze that many of you had. Put it all back together and checked it out, and suddenly I could see TONS of orbs! It almost seemed worse, but I think perhaps the fresh bulb and the cleaning of dust off of the large lens just made them more noticeable.
After thinking about it, I figured the orbs had to be due to dust on the DMD, because a black background image should have the light available to produce the orbs, unless the dust as at the DMD... if dust is on the DMD, it can reflect light before the individual mirrors are able to redirect the light away from the screen. So I tore it apart again, took the lens assembly back off, and got the light engine in the sunlight so I could see the DMD really well. Sure enough, when I held it at the correct angle, I could see a lot of dust near the surface of the DMD. But it wasn't on the surface of the top layer of glass inside the light engine: it seemed trapped behind that glass. I couldn't get to it, and I didn't really know how the DMD was attached in there and if I would cause irreparable damage trying to get to it. So I accepted defeat, and put it all back together.
When I powered the set on this time, I suddenly noticed the image was about 2-3" below the top of the screen. I was really perplexed by this, because unlike the earlier models shown in the OP, my '08 model does not have any image position adjustments. The light engine simply slides in and screws into one place. For better or for worse, they depend on their manufacturing tolerances to get the image centered close enough, then rely on overscan and electronic image adjustments to take care of the rest. But in my case, the image was now so far off that it was still an inch shy from the top after maxing out the electronic adjustments.
I took the light engine out, put it back in, and still the same. I turned the set on then looked inside one of the side access panels, and I could tell by the light passing through the lens that the problem didn't seem to be how the light engine was installed in the TV... the image was misaligned coming out of the lens! The image coming out of the lens was aimed too low relative to the rectangular mask in front of the lens. I took the LE out again, confirmed that the lens assembly was indeed installed flat/flush onto the LE. I could find no obvious reason for the image to be misaligned.
Since the lens appeared to attached to the LE correctly (at some point in this process, I took it off and put it back on, with the same problem), it seemed to me that there could only be two other places that would affect how the image is aimed prior to the image coming through the mask on the final lens: the wobulation mirror, and the DMD itself. Given that my set was unusable as it was, and the whole reason for starting this process in the first place was to get rid of dust, much of which was on the DMD itself, I decided to try it.
I took off the plate that covers that circuit board, the DMD heatsink, then the circuit board itself. Much to my relief, it was a fairly simple process. Nothing there is "hermetically sealed" (obvious by the presence of dust) or otherwise needs any special tools. The DMD is attached to the circuit board, and once removed you have full access to the glass on the LE, and the surface of the DMD (which still has some kind of glass covering on it). I didn't clean either with any fluid or cloth, I simply blew the dust off with a can of compressed air.
I put it back together, then proceeded to take off the wobulation mirror. All seemed fine in there (didn't require cleaning), so I put it back together. I then put the LE back in the TV, and strangely, the image was now only about 1/4" low (with the electronic adjustments at the same settings as they were before I started any of this). So I was pleased with that, as I knew I could easily adjust that out. Checked out the image on a black screen, and finally no orbs! NOW the set is back to looking like new!
Sadly though, I still have no understanding of what caused my initial misalignment, nor what got it fixed (well, fixed close enough). Believe it or not, I think this post is a compressed version of the actual process. I took the LE in and out many times, checking and re-checking how the lens was attached to the LE (since that was the only thing I disassembled initially), as well as how the LE attaches to the TV. The only contribution I can make is that possibly the internals of the LE may be sealed better than the earlier models: both the wobulation mirror and the internal lens were very clean on mine. At least on mine, dust in between the DMD and the glass on the light engine casting was the biggest problem, but that's not as hard to clean as you would at first fear.