In my experience, the best way to record the type of breakdown is to create "Damage" (catalog type "C") catalog code groups for Mechanical, Electrical, Material, External, or whatever others you need. Within those groups, define individual catalog codes such as Wear, Out Of Balance, Misalignment, Clearance, etc. Create a catalog profile including these code groups and assign this profile to your notification type.
The correct place to store this information is in the notification, but it can also be entered while in an order using the Notification-specific tabs available as part of the order's header data.
Paul