Sony PCV-R553DS - Manual (Page 83)

System Board 69
Configuration Jumper
There is one user-configurable jumper for CMOS Clear. The other two
jumpers are reserved (do not change).
The computer ships with CMOS Clear in the Normal position. Do not
change the position of this jumper unless directed by a technical support
person.
OM04588.VSD
CMOS Clear Clear
2-3
Normal
1-2
= default jumper
1 3
CMOS CLR
2
Reserved (do not change)
Reserved (do not change)