Old Chefettes are often over 40 years old and regrettably the spares are no longer available. It may be worth trying an auction site such as eBay for second hand parts if you are keen to keep your product in working use, although bear in mind the age of this product.
Alternatively, we have recently reintroduced the Chefette to the market, after strong customer demand.
The HM400 and the HM680 is available from all good retailers.