Our rice cooker still functions well though it had lost its on / off switch. You had to poke your finger into a hole in the body of the machine and press a little metal plate up or down. It worked but it was hardly satisfactory.
Enter Sugru, the amazing modelling paste. I fashioned a new switch out of yellow Sugru and applied it to the little metal plate with the help of the handle of a plastic fork. I then held my breath, hoping that I had not made the switch too thick such that the thing wouldn't work any more.
It appears that it's OK! Hurrah for Sugru!