Power Supply - HP 3000 9x9KS Service Manual

The power system consists of a Power Supply and a Power Monitor card. The following is a basic block
diagram of the power system:
Figure 3-1. Power System Diagram
As shown on the block diagram, the Power Monitor card interfaces to the System Board, Core I/O card,
Display Panel, key switch, and the system fans. The Power Supply and the Power Monitor cards connect
to the System Board. The System Board acts as a backplane for distributing DC voltages to all PCAs that
are installed in the system.

Power Supply

The Power Supply is a 1250VA auto-ranging supply (1700VA for HP9000 models Kx50/K260/K460/
Kx70/Kx80, HP VISUALIZE workstations, and the HP3000 979KS). There are no test points or
adjustments on the Power Supply. To fully remove power from the system, AC power must be removed.
The Power Supply does not have a circuit breaker. Whenever AC is connected, the Power Supply
continuously provides +15V House Keeping Power (HKP) to the Power Monitor card. The Power Monitor
card is active even when the Key switch is in the Standby position.
Troubleshooting 3-5