Hello DYIers and electrically-versed people!
I need your help

The timer in my hotpress is missing the usual black rings that can be pressed down to select the times we want to water to be heated.
It is not a normal plug that can be pluged/unpluged but rather built in. My question is therefore: can I replace that missing ring myself or is that something an electrician would have to do? Can't post pictures as I'm a new user, but I can send it on to anyone keen to see it as it might make more sense.
Thank you for your help,
Marianna