Cpu Board; System Board; Primary Battery; Secondary Battery - NEC VERSA P Service Manual

1-4 Technical Information

CPU Board

The CPU board is a 75-MHz (model G8SBJ) board. It connects to the system board via
connectors P1 and P2. The system integrates the Intel's Pentium P54C chip (75 Mhz inter-
nal, 25 Mhz external). The chip controls important functions including power management,
direct drive bus interface and memory management. The CPU operates at a default clock
speed of 75 MHz. It has a 32-bit internal data bus and requires an operating voltage of 3.3
volts.
The chip's floating point unit (FPU) provides an internal math coprocessor. In addition, the
microprocessor has an internal on-chip cache controller with 16 KB cache memory. (inter-
nal) and 256 KB cache memory (external).
CPU board connectors include the memory card connector (P1), the keyboard connectors
(P2 and P3), and the LCD indicator panel connector (P4). For a list of CPU board connec-
tor descriptions and an accompanying illustration, see Appendix A.

System Board

The system board (G8SBK) is inside the base unit, under the CPU board. It contains system
components including I/O subsystems. The battery charger board connects to the system
board via connector P10.
For a list of system board connector descriptions and an accompanying illustration, see Ap-
pendix A. System board specifications are listed in Table Section 1-9 at the end of this sec-
tion.

Primary Battery

The system uses a nickel metal hydride (NiMH) battery (also called "smart" battery) as its
transient power source. The smart battery communicates battery status via the LCD indi-
cator (or gas gauge). The battery pack installs in the compartment next to the PCMCIA as-
sembly. The battery uses 7.2 volts with a 3800 mAH capacity and weighs 520 grams. The
primary battery pack lasts approximately two to three hours, depending on the LCD type.
The primary battery should be discharged every 30 to 45 days using the Discharge utility.
To discharge the battery means to drain all of the battery's power. Sometimes a battery
does not last as long if not fully discharged between charges. The discharging process takes
several minutes depending on how fully charged the battery was. See Section 2, Setup and
Operation, for Discharge utility procedures.

Secondary Battery

An optional secondary battery (same battery type as the primary) can be added in place of
the diskette drive. See Section 3, Options, for installing the battery The battery uses 7.2
volts with a 3800 mAH capacity. The smart battery weighs 540 grams.