At a guess, the heating element has failed. Can you locate any supplier of spares? Is the element removable - screwed in rather than riveted? Can you disassemble the machine (making drawings of what bits go where)? Do you have access to a multimeter and are you competent to use it and understand the readings?
If you can access the element, disconnect it and see if there is any conduction between the heaters casing and one terminal or other. Ideally it will be a complete open circuit - infinite resistance. Anything less is suspect - possibly high resistance but likely less than 8000 ohms, if it's tripping a 30mA earth leakage breaker.
Also check there's continuity between the two terminals on the heater. If it's a 500W heater, you should expect about 125 Ohms.
Personally I'd welcome the opportunity to dump it and get a Panasonic. They are good.