A50
Shutdo
wn
LED
The
A50
SHUTDO
WN
LED
turning
o
indicates
some
of
A50
p o
w
er
supply
is
sh
ut
do
wn
b
y
the
A50
sh
utdo
wn
circuitry
.
There
are
t
w
o
F
AN
conditions,
rotating
and
not
rotating
when
the
SHUTDO
WN
LED
turns
o.
When
the
fan
is
rotating,
the
sh
utdo
wn
circuit
is
probably
activ
ated
b
y
the
o
v
er
curren
t
condition
on
the
p o
w
er
lines
in
the
A50
DC-DC
Con
v
ereter.
In
this
condition,
though
the
A50
p o
w
er
supplies,
+24
V,
+5
VD,
+18
V,
+7.8
V,
-7.8
V,
and
-18
V
are
sh
ut
do
wn,
the
F
an
P
o
w
er
+24
V
is
still
supplied
to
the
fan.
When
the
fan
is
not
rotating,
the
sh
utdo
wn
circuit
is
probably
activ
ated
b
y
the
F
AN
LOCK
signal
missing.
Note
Once
the
A50
sh
utdo
wn
circuit
is
activ
ated,
the
only
w
a
y
to
reset
the
circuit
is
turning
the
analyzer
p o
w
er
o.
W
ait
a
min
ute
after
turning
the
analyzer
o.
Then
turn
it
on.
3.
Check
the
A1
+5
VD
LED
a.
Remo
v
e
the
analyzer's
b ottom
co
v
er.
b.
T
urn
the
analyzer
p o
w
er
on.
c.
Lo ok
at
the
+5
VD
LED.
The
+5
VD
LED
lo
cation
on
A1
CPU
is
sho
wn
in
Figure
7-3.
The
LED
is
normally
on.
If
the
+5
VD
LED
is
o,
con
tinue
with
the
FIND
OUT
WHY
THE
A1
+5
VD
LED
IS
NOT
ON
STEADIL
Y
in
this
c
hapter.
If
the
+5
VD
LED
is
on,
the
+5
VD
p o
w
er
supply
is
v
eried
with
95%
condence
lev
el.
If
y
ou
w
an
t
to
conrm
the
last
5%
uncertain
t
y
,
p erform
steps
in
the
next
Me
asur
e
the
A1
+5
VD
V
oltage
.
Figure
7-3.
A1
+5
VD
LED
Location
7-4
P
o
w
er
Supply
Troubleshooting
Summary of Contents for 4395A
Page 10: ......
Page 26: ......
Page 34: ......
Page 77: ...Figure 2 17 B R Magnitude Ratio Phase Dynamic Accuracy Test Setup 2 Performance Tests 2 43 ...
Page 167: ...Figure 5 1 Adjustment Hardware Setup Adjustments 5 5 ...
Page 186: ...Figure 5 13 Receiver Gain Adjustment Location 5 24 Adjustments ...
Page 190: ...Figure 5 16 Receiver Flatness Adjustment Setup 1 MHz 5 28 Adjustments ...
Page 194: ...Figure 5 20 DC Bias Adjustment Setup 2 5 32 Adjustments ...
Page 196: ...Figure 6 1 Troubleshooting Organization 6 2 Troubleshooting ...
Page 206: ...Figure 7 1 Power Supply Lines Simplified Block Diagram 7 2 Power Supply Troubleshooting ...
Page 212: ...Figure 7 5 A1 CPU Connector Locations 7 8 Power Supply Troubleshooting ...
Page 220: ...Figure 8 1 Digital Control Group Simplified Block Diagram 8 2 Digital Control Troubleshooting ...
Page 240: ...Figure 10 1 Top View Major Assemblies 10 4 Replaceable Parts ...
Page 292: ...Table A 2 Manual Changes by Firmware Version Version Make Manual Changes A 2 Manual Changes ...
Page 308: ......
Page 311: ...Figure B 1 Power Cable Supplied Power Requirement B 3 ...
Page 312: ......
Page 342: ......