Elektron does not provide service on Machinedrum/Monomachine MKI devices. Some spare parts are still available to order, such as encoders, button mechanisms, and plastic button caps if you want to perform the repair yourself or enlist the help of a local electronics workshop.
Contact the Elektron Support at https://www.elektron.se/customer/tickets/ if you want to order spare parts. Note that you need an account at elektron.se to be able to create a support ticket.
You can find information about the power supply specifications here: https://support.elektron.se/support/solutions/articles/43000541580-elektron-power-supplies-psu