Appendix D Self Test
Display Test (Test 2)
When this test is selected and START switch is pressed, 2.0 is displayed. The display
then cycles through the display characters and tests the LED indicators. After that the
program returns to select mode.
A/D Test (Test 3)
This tests the A/D integrated circuit. If error indicator “E” is displayed, the START
switch must be pressed to continue.
E 3.0 – Failure when mea12 V.
E 3.1 – Failure when measuring –12 V.
E 3.2 – Failure when measuring 0.0 V.
HV Bias Test (Test 4)
Remove the detector before executing this test, which tests the high voltage bias
supply and digital pot. If an error is encountered, START switch must be pressed to
continue.
Before starting this test, turn on the bias voltage. If the test is begun with the bias off,
the bias on/off LED will blink, reminding you to turn on the bias. It takes about a
minute to stabilize the high voltage.
E 4.0 – Pot cannot be set to lowest setting.
E 4.1 – Pot fails mid-point check.
E 4.2 – Pot fails high setting check.
E 4.3 – Pot fails step-size check.
After completing the Bias test, turn off the bias switch.
Calibration Pulser Pot Test (Test 5)
Tests calibration pulser digital pot. If an error is encountered, START switch must be
pressed to continue. This test is a long one, please wait for it to finish.
E 5.0 – Pot cannot be set to lowest setting.
E 5.1 – Pot fails mid-point check.
E 5.2 – Pot fails high setting check.
E 5.3 – Pot fails step-size check.
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7401/7401VR Alpha Spectrometer User’s Manual - 9231603C
