In 2009 I bought on eBay a defective
Canon Ixus 800IS with stuck and twisted lens. Despite I had done this first time, I successfully managed to clean and reassemble the lens assemble and got it to work (although loosing tiny parts on patterned rug is no fun), thus it is *definitely possible*.
May be I am exceptionally skilled, but I took photos all steps and it is indeed quite a hell job. There are something like 14 really flimsy plastic rings places inside each other and often it is hard to see which part goes in which direction (especially without service manual). Particularly the image stabilizer(?) is floating in the middle of the barrel, held only between tiny grooves on both sides (like a record player needle in a record groove), prone to fall out by any small bump or too strong pull at the foil cable or turning threads too far. It took me several attempts to put things together in correct order and initially the mechanism flipped over at the end of zoom, ending in macro mode or something like that (by a loose light barrier cable?).
When you stare too long at that thing and try to understand what it means, you will sooner or later feel badly reminded to
this one.
Ezekiel 1: 4-21
"Now as I looked at the living creatures, behold, a wheel was on the earth beside each living creature with its four faces. The appearance of the wheels and their workings was, as it were, a wheel in the middle of a wheel. When they moved, they went toward any one of four directions; they did not turn aside when they went. When the living creatures went, the wheels went beside them; and when the living creatures were lifted up from the earth, the wheels were lifted up. Wherever the spirit wanted to go, they went, because there the spirit went; and the wheels were lifted together with them, for the spirit of the living creatures was in the wheels. When those went, these went; when those stood, these stood; and when those were lifted up from the earth, the wheels were lifted up together with them, for the spirit of the living creatures was in the wheels..."
It's not an UFO engine, but repairing it needs roughly similar skill like re-assembling a pocket watch, so it is nothing for stubby fingers. I used isopropanol and cotton swabs to remove fingerprints from image sensor and lenses. If you can get a service manual it is likely much easier to put things back together, but I think that scratched plastic grooves (like with phono records) can easily make the delicate mechanism fail, so a sand infested lens assembly (especially after many unsuccessful turns) may be beyond repair. That Canon simply replaces the entire assembly is certainly also a matter of time - it took me many hours to understand how it worked - but with a scratch at a wrong spot it may also easily get stuck or derail again.
