HP 54520 Series Service Manual page 51

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To test voltage measurement accuracy
Press Recall ,thenpress clr toset the oscilloscope to default conditions.
Set the following parameters.
Menu (hardkey} Function/Parameter Setting
Horizontal Setup repetitive
Display (mode) average
# of avg 32
Use the following table for steps 4 through 9.
Volts/div Position Supply Tolerance Limits
minimum maximum
5V 15V 30V 40.66 V 29.34 30.66 V
5V BV 15V 40.66 V 14.34V 15.66V
5V 15V 5V £0.66 V 4.34V 5.66 V
200 mV 600 mV 1.2V £26.4 mV 1.1736 mV 1.2264 mV
200 mv 600 mV 600 mv #26.4 mV 573.6 mV 626.4 mV
200 mV 600 mV 200 mv '4264 mV 173.6 mV 226.4 mV
10 mV 30 mV 60 mV +£1.32 mV 58.68 mV 61.32 mV
10 mV 30 mV 30 mv #132 mV 28.68 mV 31.32 mV
10 mV 30 mV 10 mV 4132 mV 8.68 mV 11.32 mv
7 mV 21 mv 42 mV 40,924 mv 41.076 mV 42.924 mV
7mV 21 mv mv 20.924 mV 20.076 mV 21.924 mV
TV 21 mV TmV 40.924 mv 6.076 mV 7.924 mV
Below 7 mV/div expansion is used and full scale is defined as 56 mV. The ranges from 1 to 6 mV/div are
accomplished in firmware, and will be within specifications when the 7 mV/div range is within specifications.
Initiate a V avg measurement.
Press (blue) , V avg ,and i (channel number, entry menu).
Press the channel number key (bottom row) and set the v/div range and postition
from the first line of the table.
With the supply disconnected from the channel input, note the V avg reading.
mV
Set the power supply voltage from the first line of the table.
Connect the power supply to the channel input and note the V avg reading.
Vv
Subtract the value in step 6 from the value in step 8. Record the difference in the
Performance Test Record.
On the same channel, Repeat steps 5 through 9 for the rest of the lines of the table.
With the channel keys (bottom row), set the active channel off and the next on.
Move the blocking capacitor combination to the next channel and repeat steps 4
through 11 for that channel.
Repeat steps 5 through 12 for the rest of the channels.
lf the test fails
Voltage measurement errors can be caused by the need for self-calibration. Before
troubleshooting the instrument, perform self-calibration, 0. vertical cal, (see "To Calibrate the
Firmware" in chapter 4, "Calibrating and Adjusting'). If self-calibration fails to correct the problem,
the cause may be the attenuator or main assembly.
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