HP 8340B Manual page 361

2.
Remove W8 from
AT1J2.
3.
Using
a
small, flat tool, gently pry up the ribbon
connector (W33) from
A13A1J1.
Note the
original
orientation. Do not
pull the ribbon
cable
off by hand; this
can badly bend the
pins.
4.
Disconnect
W8
from A13J1, and remove
it
from the instrument. Do not bend the small terminals on
the
A13A1 assembly with the wrench.
5.
Completely remove W14, which connects A13J2 to A12J2.
6.
Holding the A13 assembly, remove the two screws (item 8) shown
in
Figure
H-24.
7.
When
replacing the A13 assembly, apply
a thin,
continuous layer of thermal compound (HP Part
Number
6040-0454,
CDO) to each side of the A13MP1
aluminum spacer between
the
SYTM
and
the RF deck.
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CAUTION i
SWM^M^M^
Do not use silicone based thermal compound. Silicone based
oil
migrates past element sockets, switch contacts, or printed circuit board
edge
connectors, raising contact resistance, or electrically isolating the
contacts. Silicone based thermal compounds disperse into the
air,
depositing themselves anywhere in the instrument. Heat increases the
rate
of dispersion.
ATI Replacement Procedure
Refer to Figure H-23, view
D
for related assemblies, cables,
and mounting hardware locations.
1.
Remove W7
and
W8
from the
AT1
assembly.
2.
Remove three of the the four screws shown in
Figure
H-23, view
D.
3.
When removing the fourth screw,
hold
the
AT1
assembly.
4.
Ensure that W7
and
W8 are clear
of
AT1J1 and AT1J2 when you remove the AT1
assembly.
5.
To
install
a new assembly,
reverse the above procedure.
AT3
Replacement Procedure
Refer to Figure H-23, view
C
for related assemblies, cables, and mounting hardware locations.
1.
Remove the four screws
on the A17
assembly (one on each corner).
2.
Disconnect
W52
from the A15 assembly.
3.
Disconnect
W6 from the A14A1 and A16A1 assemblies,
and remove
it
from the instrument.
4.
Disconnect W5
and
W12 from the A17 low band
power
amplifier, and
remove the A17/AT3
assem¬
blies.
5.
Disconnect W53 from
the amplifier,
separating the A17 and AT3 assemblies.
HP 8340B/41B
RF
Section Repair Procedures H-41