Repair Procedures - HP 8340B Manual

Reference Loop
—
M/N
Loop
Repair Procedures
A34 REFERENCE
LOOP
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M/N LOOP
MOTHERBOARD REPLACEMENT
PROCEDURE
To remove the A34 assembly the hinged RF
deck and
A19 capacitor
assemblies must
first be
removed. Perform the following steps:
Remove the Hinged
RF
deck as follows:
NOTE:
Use of Phillips screwdrivers instead of pozidriv screwdrivers
is not
recommended.
1.
Remove
the top, bottom, and perforated side covers. Place the instrument on its
left side (as
viewed
from the front).
Refer to Figure B-35, Internal Assemblies, Cables, Mounting Hardware Location.
WW^WKW
(
CAUTION
1
JUM^MMiMiM
A10J1
A10J2 and A10J3 are precision APC 3.5 mm connectors.
The
cables and
AH
Band
1-4
detector assembly that connect to them use
SMA connectors. Extreme care should be taken when disconnecting
or
connecting an SMA cable from
a
mating
3.5 mm connector. The
SMA
cable center conductor
must align with the 3.5 mm connector center
conductor.
If
there
is
any axial force
on
the cable when disconnecting
the SMA fitting, the 3.5 mm connector center conductor may be
damaged, necessitating the replacement of the
A10 directional coupler.
Remove any axial force on the
cable
by first disconnecting the end of the
cable that does not mate with
a 3.5
mm connector or by removing the
mounting screws of the
device having 3.5 mm connectors. Perform
both
safeguards
where possible.
The
A10J2
—
A11J1
connection
is not as
critical because the
A11J1
connector
has
a captured
nut.
This nut
does
not allow axial force
on
the APC 3.5 mm center conductor
until well after
the SMA center conductor
is
disengaged.
BOTTOM OF INSTRUMENT
NOTE:
A 5/16
inch
open-end wrench
will
remove any semi-rigid cable in
this
procedure.
In
the
following text, you will be referred to
VIEW
A,
VIEW
B,
etc.
All
such occurrences refer to Figure B-25,
Internal Assemblies, Cables, Mounting
Hardware Locations.
2.
Refer to VIEW
B.
Remove W14 from the A12 assembly. Loosen W16 where it
connects to
the A13
SYTM.
Carefully disconnect the other side of W16 from the A10 assembly. Use extreme care to
avoid axial force on the W16 to A10J1 connection.
3.
Refer to VIEW
A. Using a
large pozidriv screwdriver, remove three
side panel screws (item 4) that
hold the A13 assembly to the side
rail.
4.
Refer to
VIEW
A.
Using
a
large pozidriv screwdriver, remove two side panel screws
(item 5)
that
hold the
RF
deck to the side
rail.
B-44
Reference Loop
-
M/N
Loop Repair Procedures
HP 8340B/41B