[TheLastSuperman]

I would:

• Copy the database in phpmyadmin via operations tab, this is your backup now .
• Next edit the collation on the tables in question from latin to utf8.

Do this one-by-one on the tables checking the site each time.

• If anything goes wrong simply change the last tables collation back to what it was prior and continue.

If you really mess up guess what? You made a backup before beginning haha so simply:
- Rename the current database to "samename_bak" or samename_bkp etc.
- Rename the copy you made before back to the same name of the main database.
- Assign the same database user listed in your config.php file to the copy you just renamed to the main database name - grant all privileges as well. Now your forum is fixed and back to square one.