Check
9,
CPU
Fuse
High
Lead
V
oltage
1.
Turn
on
the
4339B .
2.
Using
a
multimeter
,
check
if
the
dc
voltage
at
the
high
lead
of
the
fuse
F1
on
the
CPU
Board
shown
in
Figure
4-11
is
+560.2
V
.
3.
If
the
voltage
is
in
the
range
,
replace
the
A2
CPU
Board
Assembly
,
otherwise
replace
the
A1
Main
Board
Assembly
.
Note
If
the
multimeter
reading
is
correct,
the
F1
fuse
on
the
A2
CPU
Board
Assembly
is
most
suspicious
.
Replacing
only
the
fuse
may
x
the
problem.
Note
When
replacing
the
A2
CPU
Board
Assembly
,
refer
to
\Replacing
the
A2
CPU
Board
Assembly"
in
Chapter
3
for
handling
the
ROM
and
EEPROM
on
the
A2
Assembly
.
Figure
4-11.
Location
of
High
Lead
of
A2F1
Fuse
Check
10,
Fuse
and
Line
Switch
1.
Check
that
the
fuse
on
the
4339B
rear
panel
is
not
blown.
2.
Check
that
the
line
switch
on
the
A5
A
C
Inlet
Board
Assembly
is
not
defective
.
3.
If
passed,
proceed
to
\Check
11,
DC-DC
Converter
Input
V
oltage
",
otherwise
replace
the
defective
line
switch
or
blown
fuse
.
T
roubleshooting
4-15
