The biggest problem people face when it comes to typewriters is that they have no idea how they work. Another and even bigger problem would be the lack of someone who knows and can guide them.
To know if a typewriter is defective or not, you need a very serious knowledge baggage. There are many functions on the typewriter that can malfunction and without which the typewriter will not function properly.
The typewriter is, however, an object of the last century, consequently, today we can barely find someone who can fix it.