Quoted from sbmania:The Pinwiki doesn't provide a lot of info for these early Bally boards.
According to Pinwiki, your Kiss has a AS-2518-50 sound board. Is this correct?
https://www.pinwiki.com/wiki/index.php/Bally/Stern#/media/File:As-2518-50.jpg
There is a whole section on troubleshooting it here: