Bang, smell and smoke?

I was given an old Kenwood Chef. Brown and white/ Cream model. No idea about how it has been used. I put the whisk on and started to whisk eggs and sugar using 2/ 3 speed. Suddenly a bang and lots of smell and smoke. Not hot. I turned off and would like to fix. Help please.
Jo Loughton, February 2021


done
This could be something to do with the motor's brushes. I am in a similar position with an older KC. I believe most appliance repair shops should be able to repair this. This might help you find one: https://www.kenwoodworld.com

Ed, March 2021
link Click here to see other fixes for Kenwood Chef.