AEG Micromat 32TC 'Combination & Grill'?

Hi, I have an AEG Micromat 32TC 'Combination & Grill'. Recently it has stopped working in the sense that food/drink placed inside it does not heat up. There is power to the unit and at first you could believe it was working correctly. Usual sounds, table rotating, programmer set and counting down etc. Have checked the obvious like door switches, thermal cut-outs and terminations but have so far drawn a blank. Any suggestions pleae would be greatly appreciated. I know the microwave is dated but because of it's versatility don't really want to see it go. But spending any serious money on it would be a false economy and so the tip will be the next option. Cheers