Epson Endeavor - Manual (Page 50)

Adapter, CMOS, and PQFP jumper settings
l
Factory setting
l
* Two pin jumpers
Processor jumper settings
You need to change the processor jumper settings when you
upgrade your system by installing a new processor chip. Make
sure the jumper settings for J10, Jll, and J12 correspond to the
type of chip you installed.
Installing and Removing Options
2-7