HP 8753D Option 011

Check
the Operating
Temperature
The temp
erature sensing
circuitry inside
the A15
preregulator ma
yb
esh
utting
do
wn
the
supply
.Mak
e sure
the
temp
erature
of
the
op
en
air
op
erating
en
vironment
does
not exceed
55

C
(131

F),
and
that
the
analyzer
fan
is
operating.
If
the
fan do
es not
seem to
be
op
erating
correctly
,
refer
to
\F
an
T
roublesho
oting"
at
the
end
of
this
pro
cedure.
If
there
do
es
not
app
ear
to
b
ea
temperature
problem, it
is lik
ely
that
A15
is
fault
y
.
Inspect the
Motherboard
If
the red
LED is
still on
after
replacemen
t
or
repair
of
A15,
switc
h
o
the
analyzer
and
insp
ect
the
motherb
oard
for
solder
bridges,
and
other
noticeable
defects.
Use
an
ohmmeter
to
c
hec
k
for
shorts.
The
+5VD,
+5VCPU,
or +5VDSENSE
lines ma
y
b
e
bad.
Refer
to
the
blo
ck
diagram (
Figure
5-8
)
at
the
end
of
this
c
hapter
and
troublesho
ot
these
susp
ected
p
o
w
er
supply
lines
on
the
A17
motherb
oard.
5-10 Power Supply Troubleshooting DRAFT
3/21/106 15:12
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