Apple don't do any actual service on iPhones, iPads or iPods. They are replaced with a "replacement unit" which can be a brand new one of the production line (w

Apple don't do any actual service on iPhones, iPads or iPods. They are replaced with a "replacement unit" which can be a brand new one of the production line (which is likley in the beginning of the product cycle) or a unit with a new battery and new consumer facing parts (casing, screen, buttons, etc). The old unit is then recycled, either for parts or materials. So this is the actual guides for Apple Technicians, but they are not exactly so useful since all hardware related issues is always resolved by replacing the unit. The Macbook Pro repair guide can be of some use though. But on the other hand, iFixit will probably give you the same or more information.