Service Manuals for Canon Powershot cameras?

Service Manuals for Canon Powershot cameras?

Does anyone have a source for Service Manuals for Canon Powershot cameras? I have many working Powershot models but there is dust INSIDE the lens/ccd and I would love to take it apart to clean it. I need service guides or take-apart instructions for Powershot S100, S110, S200, SD400, SD600, SD780, SD940, SD1000, SD1100, and SD1200.