Model
3720A
4-8
TEST EQUIPMENT
4-9
Table
4-3
lists
the
test
equipment required to
carry out the troubleshooting procedure. Other
equipment with similar specifications may be
substituted if desired.
4-10
Logic Probe
4-11 The
hp
10525A Logic Probe
is
used exten-
sively in troubleshooting the 3721Al3720A System.
Power for the probe is supplied from the
LOGIC
PROBE connector on the rear panel of the 3721A
Correlator. This probe will indicate three logical
conditions:
a.
>2.5V level
is
present.
When the lamp
is
glowing brightly,
a
steady
b. When the lamp
is
extinguished,
a
steady
<1 .OV level
is
present.
c. When the lamp flashes
or
glows dimly,
a
pulse train is present, the rate of flashing being
an indication of the pulse repetition
rate.
Table
4-3
Test
equipment required for System Troubleshooting
L
Instrument Specifications Recommendation
Logic Probe
Indicates TTL logic levels and pulse trains
hp
10525A
Oscilloscope 50M
Hz
bandwidth
Dual vertical inputs
Main and delayed timebase
External triggering facility
hp
180Al1801 AI1 82
with two
hp
10004A
10: 1 Voltage Divider
Probes
A
0
c
4-2
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