F61 on screen?

When I start up my sound system it comes on for about a minute and than everything goes off, then F61 comes on screen. after that everything goes off. (I got it from my brother so,I do not have the manual book.

let me know what F61 means. or send me a manual my address
is: Raymond Jensen, PO box 2000, Kayenta, Arizona 86033 or
Fax it to 928- 697-2134 thank you.