HP 8340B Manual 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
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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