If the font size is very small, to the point that it only extends halfway across the screen, this is likely an issue where the court reporter inserted a long line of text (such as a web address), or pasted an entire paragraph as a line of text (such as the instructions about filling out an errata sheet or adding an index), in the TXT file.
Accommodating long lines of text will scale the rest of the transcript text to a very small size. If this is the problem it can be fixed if you open the TXT file in a simple text editor on your computer, find and edit the offending lines, and then reimport the file.