Dark Current Test - Agilent Technologies 1220 Infinity II LC User Manual

Dark Current Test

VWD Dark Current Test Description
The dark-current test measures the leakage current from the sample and
reference circuits. The test is used to check for defective sample or reference
diodes or ADC circuits which may cause non-linearity or excessive baseline
noise. During the test, the lamp is switched off. Next, the leakage current from
both diodes is measured. The test evaluates the results automatically.
Evaluating the VWD Dark Current Test
Table 35
Max. Sample Intensity
Max. Reference Intensity
Probable causes of test failure
Table 36
Cause
Defective sample diode
Defective sample ADC board.
Table 37
Cause
Defective reference diode.
Defective reference ADC board.
1220 Infinity II LC System User Manual
Limits
Sample circuit noise exceeds limit:
Reference circuit noise exceeds limit:
Test Functions and Calibration
Variable Wavelength Detector (VWD)
790000 counts
790000 counts
Corrective action
Exchange the sample diode.
Exchange the sample ADC board.
Corrective action
Exchange the reference diode.
Exchange the reference ADC board.
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