Test Equipment; Logic Probe - HP 3720A Service Manual

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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