HP 8753E Service Manual

Power Supply Theory
The power supply functional group consists of the Al5 preregulator and the
A8 post regulator. These two assemblies comprise a switching power supply
that provides regulated DC voltages to power all assemblies in the analyzer. The
Al5 preregulator is enclosed in a casting at the rear of the instrument behind
the display. It is connected to the A8 post regulator by a wire bus A15Wl.
Figure 12-2 is a simplified block diagram of the power supply group.
2’
OFF DURING
L ALL ON DURING
NORMAL OPERATION
NORMAL OPERAlION
\
;ON DURING
NORMAL OPERATION
sg6105e
Figure 12-2. Power Supply Functional Group, Simplified Block Diagram
Al5 Preregulator
The Al5 preregulator steps down and recti6es the line voltage. It provides a
fully regulated +5 V digital supply, and several preregulated voltages that go to
the A8 post regulator assembly for additional regulation.
The Al5 preregulator assembly includes the line power module, a 60 kHz
switching preregulator, and overvoltage protection for the +5 V digital supply.
It provides LEDs, visible from the rear of the instrument, to indicate either
normal or shutdown status.
Theory of Operation 12-5

HP 8753E Specifications

General

Brand	HP
Model	8753E
Category	Measuring Instruments
Language	English