Dont see one online anywhere... but if you're getting no display at all, I dont think its likely to be a jumper setting since I assume the jumpers were set by the last owner to work on a VGA monitor. Unless your monitor (or theirs) is very unusual, you should get SOME display even if its not perfect.
What kind of monitor do you have? What frequencies and resolutions does it support? Do you have another monitor you can test on?
What video mode do you have your Amiga set to, and what monitors do you have installed in your devs?
For what its worth the BBoAH says this:
Page 15, Table 1 "VGA To Flicker Free Video 2 adapter pin assignments"
13 - Horizontal Sync - 4
14 - Vertical Sync - 5
I assume thats on the VGA port though, not the board. The picture of the board they have has one jumper marked Bypass which I assume disables the board, and something marked clip which I suspect is a connector for something rather than a jumper.