Agilent Technologies HP 83711B Service Guide

Troubleshooting
4. Use
the direct
control function
to cause
the
analog
multiplexer
(U22)
on
the
YIG
Driver
assembly (A9)
to switch
the suspected
ABUS voltage
to
its
output.
Direct
control
information is
shown in
the following
table.
ABUS
V
oltage
HW
CTRL
ADDRESS
HW
CTRL
V
ALUE
V
oltage
+42
V
48 5 1.24
V 6
0.14 V
Digital
Ground
48 7 0
V
6
0.5
V
F
or
example
,
to
switch
+42
V
to
the
output
of
the
analog
multiplexer
on
the
YIG
Driver
assembly:
a.
Press
4
SPCL
5
.
b.
Press
4
60
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
c.
Press
4
4]8
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
d.
Press
4
5
5
on
the
numeric
keypad,
then
terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
5.
Measure
the
voltage
at
TP6
on
the
microprocessor
assembly
.
If
the
voltage
is
within
the
tolerance
shown
in
the
table
,
replace
the
microprocessor
assembly
.
If
it
is
missing
or
out
of
tolerance
,
continue
with
the
next
step
.
6.
Measure
the
voltage
at
TP4
on
the
YIG
Driver
assembly
.
The
voltage
should
be within
the
tolerance
shown
in
the
table
.
If
it
is
missing or
isn't within
tolerance
,
replace
the
YIG
Driver
assembly
.
If
it
is
within
tolerance
,
check
the continuity
of the
ABUS
cable
(W9)
with
an
ohmmeter
and
replace
it
if
necessary
.
7.
Use
the
direct
control
function
to
cause
the
analog
multiplexer
on the
YIG
Driver
assembly
to
switch
the
\no
connect"
input
to
its
output.
a.
Press
4
SPCL
5
.
b.
Press
4
60
5
on
the
numeric
keypad,
then terminate
the
entry
by
pressing
4
Hz
5
(ENTER).
c.
Press
4
48
5
on
the
numeric
keypad,
then terminate
the entry
by
pressing
4
Hz
5
(ENTER).
d.
Press
4
0
5
on
the
numeric
keypad,
then terminate
the entry
by
pressing
4
Hz
5
(ENTER).
8.
Measure
the
voltage at
TP4 while
disconnecting the
ABUS cable
from
each
of
the
other
assemblies
(one at
a
time).
The
voltage
will
change
to
a
non-negative
value
when
the
ABUS
cable
is removed
from
the
assembly
that
is
loading
the
ABUS
down.
Replace
the
assembly
that
is loading
the
ABUS
down.
If
no
change
is
noted
after
the
ABUS
cable
has
been
disconnected
from all
assemblies,
replace
the
ABUS
cable
.
MSB
Errors
Error Group Description
18 = 100 YIG Driver MSB check, value = 256
18 = 1000 YIG Driver MSB check, value =
512
18 = 10000 YIG Driver MSB check, value = 1024
18 = 100000 YIG Driver MSB check, value = 2048
18 = 1000000 YIG Driver MSB check, value = 4096
18 = 10000000 YIG Driver MSB check, value = 8192
1. Install the YIG Driver assembly in the service position. Refer to the procedure \YIG Driver
Board Assembly A9" in Chapter 5 of this manual.
Troubleshooting 1-21

Agilent Technologies HP 83711B Specifications

General

Brand	Agilent Technologies
Model	HP 83711B
Category	Test Equipment
Language	English