Tony, you didn't say what mount configuration the C8 is on, but the following link will take you to Company Seven web-site notes page. From there you can download the original Celestron C8 and Celestar C8 manuals -
http://www.company7.com/library/celestron/notes.html
Also here is the Celestron site with the later C8 mounts/otas, you may need to go to their 'download archives' forn the older C8's.
http://www.celestron.com/c3/downloads.php
Cheers
Garin