CTD00 tumbler dryer stops as soon as I release the on/off button?

Hi, I have a hotpoint tumble dryer, model CTD00, it has recently stopped working. The tumble dryer only works if I continue to hold the on/off switch, as soon as I release the on/off switch, the tumble dryer stops. Whenever I press the on/off button, it produces a spark, if I hold the button for too long, it the breaks the circuit in my fuse board in my home. I have tried replacing the on/off button but the same problem keeps persisting. The motor seems to be working fine and I believe the main fault lies in the power supply. Thank you for your help.