Dc Voltage Function - 44491A Offset Test; Preliminary Steps - HP 3457A Service Manual

Performance Tests 3457A
4-12. PERFORMANCE TESTS
The Performance Tests are divided into 6 main tests, DC Volts, AC Volts, DC Current, AC Current, Ohms,
and Frequency. Each test can be performed independently of the others. The steps within each test,
however, should be performed in order.
VOLTAGE
SOURCE
Figure 4-1. DCV Performance Test Connections
The temperature of the environment where these tests are to be performed must be »
within 5° C of the temperature where the instrument was calibrated. The instrument
was calibrated at the factory in an area with a temperature of 24° C (+ 1° C).
4-13, Preliminary Steps
1. Turn the instrument ON and allow a one hour warm-up period.
2. Be certain all external inputs are disconnected from the HP 3457A. Run the TEST routine. The test
result must read "SELF TEST OK". If the display shows "TEST FAILED", the instrument probably needs
repair.
3. Run the AUTO CAL routine. (Press the AUTO CAL key, enter the number | and press the ENT key).
DC Voltage Performance Tests
4-14. DC Voltage Function - Offset Test
4-15. Equipment Required. A low thermal short (copper wire) is required for this procedure.
1. Connect a low thermal short across the Front Panel HI and LO Input Terminals.
2. Set the HP 3457A to the DC Voltage function (DCV) and the number of digits displayed (DIGITS
DISP) to six.
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