Isolation Logic Troubleshooting - HP 3456A Operating And Service Manual

Model 3456A
2. Unsolder and remove one side of jumper A30JP)
from the A30 board.
3 .
Connect pin 4 o f A30U9 to + 5 V.
4. Turn the 3456A On.
5. Troubleshoot the 3456A using the procedure in
Figure 8-8-4.
j . Move the Clock of the Signature Analyzer to
A30J32-C.
k. Check for the following signatures at A30UI3:
1#
A30U 13
Pin
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
I.
If any signatures are wrong, replace u n .
m . I f the signatures are good, do the following:
1 . Turn the 3456A Off.
2. Reconnect the cable to the Isolation Logic Con­
nector (A3J7, Schematic 12).
3 . Move A30J35 and J36 to the Run ( 1 and 2) posi­
tion.
4 . Move A30J33/J34 t o the " J " (first) position.
5. Move the Clock of the Signature Analyzer to
A30J32-B.
6. Turn the 3456A On.
7. Set the 3456A to Trigger HOLD and 4WR Ohms
Function.
8. Set the 3456A to the following functions
take the signatures on A30P21 as follows.
Function A30P21
DCV
DCV
DCV
DCV
ACV
ACV
ACV
ACV
2WRO
2WRO
2WRO
2WRO
9. I f any signatures are wrong, replace A30U 16 or
U 1 3 .
1 0 . I f the signatures are good, set the clock o f the
Signature Analyzer to: (
Signature
0030
0020
0020
0020
0030
0030
0030
0030
#
Pin
0000
0000
2
3
4 000 1
0004
5 000 7
0000
2
3
0000
4 0001
0000
5
0004
2
3
4 0003
5 0007
�
)
1 1 . Set the 3456A to the following functions and
take the signatures on A30P21 as follows.
Function
DCV
DCV
DCV
DCV
ACV
ACV
ACV
ACV
2WRO
2WRO
2WRO
2WRO
12. I f any signatures are wrong, replace A30UI6 or
U I 3 .
1 3 . I f the signatures are good, replace A20U702.
8·8·39. Isolation logic Troubleshooting.
8-B-40. To troubleshoot the Inguard Isolation Logic,
do the following:
a. Press the 3456A's RESET button and then the
TEST button.
b. Set the instrument to Test #3 by pressing the 3 ,
STORE. and 5 (COUNT) button.
c. Connect the vertical input of an oscilloscope to the
junction of A30R14 and R I 5 (as shown below). Using
the set-up information in Figure 8-B-5. check for the
waveform shown in the figure.
d . I f the waveform is missing or incorrect, replace
A30T2.
and
Connect _
to here.
2 V
Figurs
A30P21 Signature
Pin #
0006
2 0002
3
0000
4 0007
5
0006
2 0002
3
0000
4 0007
5
2 0002
3 000 6
0000
4 0007
5
- A l 1 -
- A 1 2 -
- A 1 3 -
- A 1 4 -
- A 1 5 -
5 psec Neg. Trig.
8·8·5. Isolation Logic Input.
8-8- l l a/8-B- 12a
Service