have a look at the switch button , on the inside you will see a small slot (hole) push something thin down this and prize to the side the button will lift off (its like a hook thing). underneath the button you will see a torx screw undo this and Bob your uncle.
Richard North Wales
April 2011
sorry typing not to good DC04 not 40 no screws that I can see
Malcolm
March 2011
dysonmedic.com will show you how
be suspicious of the integrity of the wires inside the cable close to the point where the cable bends as it comes from the plug - a common problem
Peccavi
March 2011
Not sure about the 40, but most dyson uprights, have 2 screws behind the hose on the back, remove them and the switch is clip in
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