HP 8340b - Page 359

5.
Remove
the
five
screws
(item 2)
that
hold
the
combined
A8
and
A9
assemblies
to
the
RF
deck.
6.
Remove
the
screw
(item 3)
that
holds
the
A8
casting
to
the
A62
motherboard.
Note
that
this
screw
is
longer
than
the
five
other
screws
(item
2).
7.
Carefully
remove
the
A8/A9
assembly
from
the
instrument.
8.
Remove
W9
completely.
When
loosening
W9
from
A9J1,
do
not
damage
the —10V
terminal
on
the
A8
assembly
with
the
wrench.
9.
Separate
the
A8
and
A9
assemblies,
using
a
1/4
inch
nut
driver
to
remove
the
four nuts
at
the
corners
of
the
A9
assembly.
10.
To
install
a
new
A8
assembly,
reverse
the
above
procedure.
When re-installing
W10,
completely
tighten
one
end
before
you
start
the
other.
A9
Low
Band Pulse
Mod
Replacement Procedure
Refer
to Figure
H-23
for
related
assemblies,
cables,
and
mounting
hardware
locations.
1.
Remove
W10
from
the
instrument.
You
may
have
to
place
a
special
5/16 inch
slotted
box
end
wrench
(see
equipment
required,
above)
on
A15J2
to
keep
the
A15
assembly
from
turning
when
you
remove
W10
from
A15J1.
2.
Using a
standard
5/16
inch
wrench
to
remove
W10
from
A15J1.
3.
Remove
W10
from
the
A9
assembly
and
set
aside.
4.
Disconnect
W9
from
the
A9
assembly
by first
loosening
its
connection
to
the
A8J1
connector.
5.
Remove
the
connection
to
A9J1
carefully,
do
not
damage
the
—
10V
terminal
on
the
A8
assembly.
6.
To
install
a
new
A9
assembly, reverse
the
above
procedure.
A10
Directional
Coupler
Refer to
Figure
H-23 for
related
assemblies,
cables,
and
mounting hardware
locations.
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|
CAUTION
1
^•WxM^Wl
A10J1,
A10J2,
and
A10J3
are
precision
3.5
mm
connectors.
The
cables
and
the
high
band
detector
assembly
that
connect
to
them
use
SMA
connectors.
Take
extreme
care
when
disconnecting
or
connecting
an
SMA
cable and
a
precision
3.5 mm
connector.
The
SMA
cable
center
conductor
must
align
with
the
3.5
mm
connector center
conductor.
Any
axial
force on
the
cable
when
you
disconnect
the
SMA
fitting
can
damage
the
3.5
mm connector center conductor,
and
the
A10
directional
coupler
will
have
to
be
replaced.
Remove
the axial
force
on
the
cable
by
first
disconnecting
the
end of
the
cable
that
does
not
mate
with
the
3.5
mm
connector,
or
by
removing
the
A10
assembly
mounting
screws.
Do
both
where
possible.
The
A11J1
connector
has
a
captured nut
that
does
not allow
axial force
on
the
precision
3.5
mm
center
conductor
until
well
after
the
SMA
center
conductor
is
disengaged.
HP 8340B/41B
RF
Section Repair
Procedures
H-39