I called Roland in California and they were able to send me an XP-50 manual for 9 bucks. I suppose they would send you one for the JV90.

I got their number from the web-site.

Corporate Offices
Roland Corporation U.S.
5100 S. Eastern Avenue
Los Angeles, CA 90040-2938

P.O. Box 910921
Los Angeles, CA 90091-0921

Phone: (323) 890-3700
Fax: (323) 890-3701

If I remember right, that number was the one I called and ordered my XP-50 manual.

Peace,
Bob