Microwave (Muirhouse EH4)

Delonghi combination microwave. It works well but when it's switched off occasionally a very faint short duration scratchy sound can be heard. I don't know what it is but it's making me feel nervous. I don't want to take it to an electrician and run up a big bill so I've decided to get rid of it. If you know what you're doing with this kind of thing then you're welcome to come and take it away.