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SECTION 4
Seruice Informtim
Table 4-2.
Path Isolation
Tests
rest
No.
1
2
3
4
ii
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
-
-r
Path Isolation
Row A, Co1 1 to Row B, Co1 2
Row 8, Co1 2 to Row C, Co1 3
Row C, Co1 3 to Row D, Co1 4
Row C, Co1 4 to Row D, Co1 5
Row C, Co1 5 to Row D, Co1 6
Row C, Co1 6 to Row D, Co1 7
Row C, Co1 7 to Row D, Co1 8
Row C, Co1 8 to Row D, Co1 9
Row C, Co1 9 to Row D, Co1 10
Row C, Co1 10 to Row D, Co1 11
Row C, Co1 11 to Row D, Co1 12
Row D to Row E
Row E, Co1 1' to Row F, Co1 2
Row F, Co1 2' to Row G, Co1 3
Row G, Co1 3' to Row H, Co1 4
Row G, Co1 4' to Row H, Co1 5
Row G, Co1 '5 to Row H, Co1 6
Row G, Co1 6' to Row H, Co1 7
Row G, Co1 7' to Row H, Co1 8
Row G, Co1 8' to Row H, Co1 9
Row G, Co1 9' to Row H, Co1 10'
Row G; Co1 IO' to Row I?, Co1 11'
Row G, Co1 11' to Row H, Co1 12
Test Equipment
Crosspoints
Locations
Closed
Row A and Row B
Row B and Row C
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row C and Row D
Row D and Row E
Row E and Row F
Row F
and
Row G
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Row G and Row H
Al and B2
B2 and C3
C3 and D4
C4 and D5
C5 and D6
C6 and D7
C7 and D8
C8 and D9
C9 and D10
Cl0 and Dll
Cl1 and D12
None
El and FZ
F2 and G3
G3 and H4
G4 and H5
G5 and H6
G6 and H7
G7 and H8
G8 and H9
G9 and HlO
G10 and Hll
Gil and H12
4.4.8
Differential
and Common
Mode
Isolation
Tests
These tests check the leakage resistance (isolation)
be-
tween high (H) and guard (G) (differential),
and from
high and guard to chassis (common mode) of every row
and column. In general, the test is performed by applying
a voltage UOOV) across the terminals and then measuring
theleakagecurrent.
Theisolationresistanceisthencalcw
lated as R = V/I. In the following
procedure, the Model
617 functions as a voltage source and an ammeter. In the
V/I function,
the Model 617 internally
calculates there-
sistance from the known voltage and current levels and
displays the resistance value.
1. Turn the Model 707 off if it is on.
2. Remove thematrix
card column jumpers if installed.
3. Install the Model 7076 in slot 1 of the Model 707.
4. ConnecttheModel617toROW
AasshowninFigure
4-7 to measure differential
isolation.
Make sure The
voltage source is in standby. Also, make sure there
are no other connections to the card.
T
WARNING
The following
steps use high voltage (1OOV).
Be sure to remove power from the circuit be-
fore making connection
changes.
5. On the Model 617, select the 2pA range, and enable
zero check and zero correct in that order. Leave zero
correct enabled for the entire procedure.
6. On the Model 617, set the voltage source for +lOOV,
and select
the
200nA
current
range. Make sure the
voltage source is still in standby.
7. Place the Model 617 in the V/I measurement
func-
tion by pressing SHIFT OHMS.
8. Turn on the Model 707, but do not program any
crosspoints to close. All crosspoints must be open.
9. On the Model 617, disable zero check and press OP-
ERATE to source 1OOV.
10. AfterallowingthereadingontheModel617tosettle,
verify that it is >lGQ. Thismeasurement
is theleak-
age resistance (isolation) of ROW A.
11. Place the Model
617 in standby
and enable zero
check.
12. Program the Model 707 to close crosspoint Al.
13. On the Model 617, disable zero check and press OP-
ERATE to source +lOOV.
4-9
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