Compaq 4000N - Manual (Page 135)

Technical Reference Guide
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September 1997
7-1
AC Input
To
System
Board &
Drives
Chapter 7
POWER and SIGNAL
DISTRIBUTION
7. Chapter 7 POWER SUPPLY AND DISTRIBUTION
7.1 INTRODUCTION
This chapter describes the power supply and method of general power and signal distribution in
the Compaq Deskpro 4000N and 4000S Personal Computers. All models use a 76-watt power
supply assembly. Power distribution is basically similar in all models. Topics covered in this
chapter include:
♦
Power supply assembly/control (7.2) page 7-1
♦
Power distribution (7.3) page 7-4
♦
Signal distribution (7.4) page 7-6
7.2 POWER SUPPLY ASSEMBLY/CONTROL
This system features a power supply that is controlled through programmable logic (Figure 7-1).
This allows several options for how and when the system can be powered up.
Figure 7–1. Power Supply Assembly, Block Diagram
Power Supply
Assembly
Power
Control
Logic
+5 VDC
-5 VDC
+12 VDC
-12 VDC
+3.5 VDC
Power On
Power
Button System Board
PS On Fan Off-
+5 AUX
NIC
I/O Controller
PINTA
On Cntrl
Fan
Fan Pwr
SW1 -6