I don't have a service manual for you, however I've taken apart my Powershot S500 several times, including opening the lens/sensor assembly to successfully clean dust on the sensor.

I documented it in this teardown report here on ifixit. From other Powershot cameras I have seen and poked around with, the construction of others is very similar so even if you're wanting to do this with a different model, you may find my photos instructive.

I also notice there are some additional [[Family:Canon_Camera|repair guides for other Canon models]] here on ifixit now - take a look at those also.

if you are handy with taking apart things and handling tiny screws and delicate ribbon cables, you may be able to take apart your camera without a service manual. basically just take it apart one screw at a time, save and label where the screws go, and perhaps take photos along the way (that's how my teardown photos came about). then reverse the process when done. good luck!

Here's a link to the repair manuals for the Canon Powershot - Pro1, S10, S45, A70, A95, IXUS II/SD100, it's not everything you want but should give you a very good idea of how they work: http://qman.fotokala.ee/

Google the following: "POWER SHOT S400 - IXUS 400.pdf" (without the quotes). You will find the parts list that gives you an idea on how to dismantle it.

I found the document here: http://www.micro-tools.net/pdf/Canon/POW...

jflarin

Try to find here http://service.gex-bbs.ru/canon_camera.

Our Canon Camera repair manual section is growing constantly. We have quite a few PowerShot models already, and we get more every few months.