Agilent Technologies 6621A, Service Manual

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3-19 Turn On/Off Overshoot.
This test measures the
amplitude of any transients in the output during turn on or
turn off of the supply.
a. Turn off the supply and connect an oscilloscope across
the + V and - V terminals of the output to be tested.
b. Set the oscilloscope to 50 mV/div, dc coupled, 1
sec/div, and + slope.
c. Turn on the supply while observing the oscilloscope.
The maximum transient amplitude should not exceed
± 100 mV. Repeat test by observing the scope after
turning off the supply.
d. Repeat the test (steps a through c) for each output in
your supply.
3-20 Overvoltage Protection. The following tests check the
operation and accuracy of the fixed OV, programmable OV,
and the external OV protection circuits.
Fixed OV Test. This test verifies that the fixed OV circuit will
be activated when the output is about 20% above the High
Range Full Scale Voltage value.
a. Turn off the supply and connect an external power
supply to the output to be tested as shown in Figure 3-
10.
b. Do not turn on the supply. This test is performed with
the ac power turned off.
To avoid possible damage to the output under test, the
external supply should be current limited to less than 1 amp.
c. Set the external power supply to 20 V (for
40WLV/80WLV outputs) or to 50 V (for
40WHV/80WHV outputs).
d. Slowly increase the voltage of the external supply until
the overvoltage circuit in the supply under test trips.
This is indicated by a sudden drop in the voltage of the
external supply. The fixed OV circuit should trip
between 22.7 V and 25.7 V (for 4OWLV/80WLV
outputs) or between 56.8 V and 63.5 V (for 40WHV/
80WHV outputs).
e. Repeat steps a through d for each output in your
supply.
3-9