Hi Frederik,
if you are going to multiple transaction for single business partner than case management will make sense.
In your case you can go with service order with out a template option. The hardware need to be an product, for that product categorization need to be done. Definitely some enhancements involved here.
1. Search and confirm or create a business partner.
2. Enter the hardware as product.
3. Multilevel categorization select the printer and repair, Categorization option need to be with respect to the hardware.
May be based on your business requirement you can have activity as followup to the service order with respect to the status profile.