Seeking schematic or owners manual for Telefunken ELA E130b "stereo width control"

Found the unit on Ebay for little more than shipping costs last year. Although I can get it to perform the basic operations, the multi pin I/O connector has more options than I can identify by trial and error; and I'm probably not utilizing all this box has to offer. Even just a pin diagram would be a big help.

thanks.
steve