I have a text file called HELLOWORLD.TXT created with Apple Writer II. When I open it in the File View, it shows up as blank in the "Text" view:

The "Hex Dump" view shows the correct characters ("Hello"):

Exporting as "ASCII text file" creates a completely empty file (0 bytes). Exporting as "Raw disk data" produces the correct text file, which is viewable in any text editor.