I always liked how Korg did stuff. Yamaha were always "we do not distribute spare parts or service manuals, do not even ask, they are only for authorised service centres, we'll take you to court if you try to acquire them, we will take anyone distributing them online to court". Roland were more like "You can order spare parts if you set up an account, some guy in Germany might know, we don't give out service manuals to anyone except authorised service centres, you might find some somewhere, I don't know"
And then Korg basically said (when approached, years ago) "we only supply spares and service manuals to authorised service centres, do not even attempt to look for service information online, and especially do not go looking in ftp.korg.com/pub/service/dealeronly/"...