Agilent Technologies 8453 Operator's Manual page 193

Table 44
Diagnostics and Troubleshooting
General Troubleshooting Hints
Measurement Results Indicate Excessive Drift
The selftest (only Agilent ChemStation software), lamp intensity, and
stability diagnostics within the software can aid in diagnosing problems
within the optical system which contribute to excessive drift. Causes and
solutions for excessive drift are shown in Table 44.
Excessive Drift
Possible Causes
Variations in temperature.
Sample degrades with time and/or exposure
to light.
Floating particles in the cell.
Deuterium lamp may burn unstable.
Tungsten lamp may burn unstable
Spectrophotometer lamp supply (SLS) board
may supply unstable power.
Spectrophotometer data acqusition (SDA)
board may be defective.
Main power supply (MPS) may supply
unstable power.
Spectrograph electronics may be defective.
Action
Ensure that the environment in which the
spectrophotometer is being used is stable.
The photodiode array temperature may be
monitored from within the software to verify
PDA temperature stability.
Use the spectrophotometer without sample.
If the problem is found to be sample related,
i.e. sample exposure to light, limit the
amount of light by the environment and/or
shorten the integration time to limit the
amount of light during the measurement or
use filter wheel to cut out the energetic low
UV range.
Filter sample before measurement.
Exchange lamp.
Exchange lamp.
Exchange SLS board.
Exchange SDA board.
Exchange MPS.
Exchange optical unit.
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