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8-320.
HP-IB Interface Assembly (AS Board)
Troubleshooting
8-321.
At Power-Up, the HP-IB interface is tested.
An ERROR: 1/0 message will appear on the display if
the test did not pass. If the test passes, the address of
the interface will appear on the display.
NOTE
If all the switches on the DIP switch, ASS1, are
set to 1 (open or upward) the error message
will appear on the display.
8-322.
If the 1/0 address diagnostic fails and the
counter passes all other diagnostics, verify that the
ribbon cable ASW1 is properly seated in its mother-
board connector A 1]8.
8-323.
Verify the following voltages on the AS board
assembly:
SIGNAL NAME
TEST POINT
RANGE
+S volts
+S volts cmc
+S (TP1)
U2, pin 24
±0.2 volts
±0.2 volts
8-324.
Verify that a 3.S MHz (nominal) clock signal is
present at US pin 2.
8-32S.
A signature analysis mode is available for the
AS board assembly. This technique is helpful to
determine failed components on the AS assembly.
For problems involving a particular controller, it is
recommended that an HP S9401A Bus Analyzer and
logic analyzer be used to determine the cause of the
problem. As an initial test, verify that the interface
responds properly to the HP-IB test program found in
Section IV. Also verify that the controller interface is
functioning properly. An HP-IB test tape (HP part
Number S9300-10002, Revision G) is available for use
with the HP8S desk top controller.
8-326.
To perform signature analysis for the AS
assembly, proceed as follows:
a.
Remove the ac power cord from the rear panel
of the counter.
b.
Remove the HP-IB assembly from the counter.
c.
Set all of the switches on the DIP switch, ASS1,
to 1 (open or upward).
d.
Connect +S volts and ground to the AS
assembly. The +S volts source can be either the +S volt
supply in the counter or a separate +S volt supply that
has as good or better regulation than that of the
counter's power supply.
If
the counter is used as the
+S volt source, it is convenient to clip on to TP2 on the
motherboard for the +S volts and TP10 for the
ground. On the AS board, +S volts may be connected
to the lead nearest W1. Ground may be connected to
HP S384A and HP S38SA
Service
the lead of C4 nearest to W1. (Do not use ]3 pin 8 for a
power supply connection.)
e.
Connect a signature analyzer such as the HP
SOOSB to the AS assembly as follows:
TIMING POD
TEST POINT
START /ST/SP (green lead)
ST (TP2)
STOP/QUAL (red lead)
SP (TP3)
CLOCK (yellow lead)
CK (TP4)
(black lead)
(TPS)
f.
Make the following settings to the HP SOOSB:
CLOCK
negative slope
START
negative slope
STOP
negative slope
g.
Connect a test lead between PAT (TP1) of the AS
assembly and ground. If the counter is used as a +S
vol~
supply for the AS assembly, reconnect the line
cord to the rear panel and switch the counter on.
h.
Remove the test lead from the PAT test point.
The microprocessor checks this line at Power-Up and
then goes into the signature analysis mode. The PAT
point must be grounded on Power-Up to generate
START and STOP signals, however, a valid signature
can only be taken at this point with the grounding clip
removed. All other signatures on the AS board should
remain identical regardless of the status of PAT (TP1).
i.
After verifying the characteristic signatures, Vee
and ground, verify the signatures shown in Figure 8-
50.
It is recommended that signatures on the HP-IB
microprocessor, US be checked first as this is where
the signal activity is generated.
8-327.
The signature analysis routine does not verify
the REN line and the 1/0 lines between the AS
microprocessor and the main microprocessor on the
motherboard. Install the AS assembly into the instru-
ment and reset the ASS1 Dl P switch to its orignal
setting. Enter the following program into an HP8S and
connect the HP-IB interface to the counter. Note that
for line 10 in the program, the appropriate address for
the counter should be entered (714 is used for
example only).
10
Remote 714
20
Local 7
30
Go to 10
40
End
8-328.
Run this program and verify activity at
ASUS(27). If there is no activity at this point, trace back
through U4D, U4A, and U2 to locate the fault. Also,
verify activity on US, pins 3, 4, S, 6, 16, 17, and 18. If
there is no activity on these lines, a problem may exist
in the interface between the A 1 Microprocessor
assembly and the AS HP-IB Interface Assembly.
8-43
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Troubleshooting
