HP 8753D Option 011 User Manual

Line P
ow
er Module
The
line p
ow
er mo
dule includes
the
line
p
o
w
er
switc
h,
v
oltage
selector
switch,
and main
fuse.
The
line
p
o
w
er
switc
h
is
activ
ated
from the
front
panel. The
voltage
selector switc
h, accessible
at the
rear panel,
adapts the
analyzer to
lo cal
line v
oltages
of
appro
ximately
115
V
or
230
V
(with
350 V
A
maxim
um).
The
main
fuse,
whic
h
protects
the
input
side of
the preregulator
against
dra
wing
to
o
m
uc
h
line
current,
is also
accessible at
the rear
panel.
Refer
to
the
HP
8753D Network
Analyzer
Instal lation
and Quick
Start
Guide
for
line
v
oltage
tolerances
and
other
p
o
w
er
considerations.
Preregulated V
oltages
The
switching
preregulator con
v
erts
the
line
v
oltage
to
sev
eral
DC
v
oltages.
The
regulated
+5
V
digital
supply
go
es
directly
to
the
motherb
oard.
The
follo
wing
partially
regulated
voltages
are
routed
through
A15W1
to
the
A8 p
ost regulator
for nal
regulation:
+70
V +25
V
+18
V
0
18
V
+8
V
0
8
V
Regulated
+5
V
Digital
Supply
The
+5VD supply
is regulated
b
y
the
con
trol
circuitry
in
the
A15
preregulator.
It
go
es
directly
to
the
motherb
oard,
and
from there
to all
assemblies
requiring a
lo
w
noise
digital
supply
.
A
+5
V
sense
line
returns
from
the
motherb
oard
to
the
A15
preregulator. The
+5V
CPU
is
deriv
ed
from
the
+5VD
in
the
A8
p
ost
regulator
and
go
es
directly
to
the
A19
graphics
system
pro
cessor.
In
order
for
the
preregulator to
function,
the
+5
V
digital
supply
m
ust
b
e
loaded
b
y
one
or
more
assem
blies,
and
the
+5
V
sense
line
m
ust
b
ew
orking.
If
not,
the
other
preregulated
v
oltages
will
not
b
e
correct.
Shutdo
wn
Indications:
the
Green
LED
and
Red
LED
The
green LED
is
on
in
normal
op
eration.
It
is
o
when
line
p
o
w
er
is
not
connected,
not
switc
hed
on,
or
set to
olo
w, or
if the
line
fuse
has
blo
wn.
The
red
LED,
whic
his
o in
normal op
eration,
ligh
ts
to
indicate
a
fault
in
the
+5
V
supply
.
This
ma
y
b
e
an
o
v
er/under
line
v
oltage, o
ver
line curren
t,
or
o
v
ertemp
erature
condition.
Refer
to
the
troublesho
oting
c
hapters
for
more
information.
A8
P
ost
Regulator
The A8 p ost regulator lters and regulates the DC v
oltages receiv
ed from the
A15
preregulator. It pro
vides fusing and
shutdown circuitry for individual v
oltage supplies. It
distributes regulated constan
tv
oltages to individual assem
blies throughout the instrumen
t. It
includes the o
vertemperature sh
utdown circuit,
the v
ariable fan speed circuit, and the air o
w
detector. Nine green LEDs pro
vide status indications for the individual v
oltage supplies.
Refer to the P
ower Supply Blo c
k Diagram lo cated at the end of Chapter 5, \P
o
wer Supply
Troubleshooting," to see the voltages provided by the A8 post regulator.
Voltage Indications: the Green LEDs
The nine green LEDs along the top edge of the A8 assembly are on in normal op eration, to
indicate the correct voltage is presentineach supply. If they are o or ashing, a problem is
DRAFT
3/21/106 15:14
Theory of Operation 12-5
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HP 8753D Option 011 Specifications

General

Brand	HP
Model	8753D Option 011
Category	Measuring Instruments
Language	English