Keithley 237 - 3.6 DISASSEMBLY INSTRUCTIONS

SECTION2
Operation
2.6.2
Model 7152
Low
Current Matrix
Card
The
Model7152
is
a 2-pole, 4 x
Slow
current
matrix
card
( <1
pA
offset
current)
that
can
be
controlled
by
the
Model
705
or
706
scanner.
Figure
2-20
shows
a
two
Source
Meas-
ure
Unit
test
configuration.
In
this
example,
OUTPUT
HI
and
OUTPUT
LO
of
each
Source
Measure
Unit
are
inde-
pendently
switched,
allowing
maximum
versatility.
This
test
configuration
has
five
DUT
test
pins.
However,
additional
DUT
pins
can
be
made
available
by
adding
more
Model
7152
matrix
cards.
Each
additional
matrix
+
card
(row
connected)
can
add
five
DUT
pins
to
the
test
configuration.
Source
Measure
Unit
and
test
fixture
connections
to
the
matrix
card
are
accomplished
using
Model7152-
TRX
ca-
bles.
These
cable
assemblies
are
terminated
with
3-slot
triax
connectors.
On
each
Source
Measure
Unit,
notice
that
the
banana
jack
is
used
to
access
OUTPUT
LO
rather
than
the
triax
connector.
This
allows
OUTPUT
LO
to
be
routed
to
the
signal
path
of
the
matrix.
On
the
Source
Measure
Unit
triax
connector,
OUTPUT
LOis
located
on
the
inner
shell
which,
through
normal
triax
connections,
would
put
OUTPUT
LOon
the
guard
path
of
the
matrix
card.
Figure
2-21
shows
the
cable
modification
required
to
connect
the
OUTPUT
LO
banana
jack
to
the
3-slot triax
cable
..
Test Fixture
Inner
Panel
7
~!b~RX{
I I I I I
7152-TRX
Cable
~R
Col
,
"
.I
"
,
"
.I
NOTE
:
Do
not
connect
guards
to
the
OUT
or short
them
together.
If
guarding
the
inner
panel,
only
connect
one
guard
line
to
it.
ow
Output
HVGuard
~(
~-
'
Unit
#1
Output
LO
(Banana
Jack)
5
....
~
4
.:,
,,
Output
HVGuard
Unit
#2
Output
LO
&-
(Banana
Jack)
Triax
to
Banana
Plug
Modification
(See
Fig.
2-21
).
CAUTION
To
prevent
damage
to switching
cards,
do
not
switch
more
than
200V
or
500mA
Also,
incorrect crosspoint
closures
will
short various
signal
or
guard
lines
and
may
cause
instrument
or
OUT
failure.
Figure
2-20.
Multi
Unit
Connections
to
Model
7152
2-24
+
'"
1
2
3
4
5
'
,
,
,
...
1\'
,,
'
~
,,
~
'
7152
Matrix Card
L
Crosspoint
(1
of
20)
_.......
IF
Signal
o-
-
Guard
1