Epson RC620 CU Manual page 194

Maintenance 6. Maintenance Parts Replacement Procedures
BIOS (1) Insert the battery diagonally into the battery holder.
Backup Battery
NOTE

(Faster)
Installation
(2) Make sure that the battery is firmly inserted in the holder and mount the CPU board
(3) Connect the following items to the Controller.
NOTE

(4) Turn ON the Controller power and keep pressing the <Delete> key.
178
The battery has front and back sides. When inserting the battery, make sure
that "+" mark of the battery is visible.
on the Controller.
Refer to Maintenance: 6.4.2.1 CPU Board (Faster).
Keyboard Mouse
Display Power plug
Connect the keyboard with PS/2 port of the CPU board.
If you use the USB keyboard, connect it with PS/2 port using PS/2 branch cable
(attached to the Controller).
BIOS window will be displayed.
RC620 Rev.8