The power and self timer are part of the same switch on the top plate. To turn on the power, you push the switch forward, to engage self timer, there is a button just infront that is then held down, and the switch is pushed forward a few more milimetres, which exposes the letters ST.
The image is with self timer mode selected. However without pressing the button or pushing the switch up to ST it still does a self timer.

Hi, my Father has a P30N which is stuck on the 10 second timer function. It fires the shutter like normal after the 10 seconds, but will not go back to normal operation. Does anyone have any ideas how to fix it? Thank you in advance.