Thermo Scientific Accela PDA Hardware Manual page 118

7
Troubleshooting
Detector-Related Problems
Table 5. Detector-related problems (Sheet 2 of 4)
Symptom
Random noisy
baseline.
Excessive baseline drift. Contaminated LightPipe flowcell.
98 Accela PDA Detector Hardware Manual
Cause
Contaminated LightPipe flowcell.
Leak in sample inlet line.
Bubble trapped in LightPipe flowcell.
Leaking LightPipe flowcell.
Insufficient lamp warm-up.
Aging or defective lamp.
Ground loop problem between
integrator and detector.
Dirty LightPipe flowcell or lamps.
Integrator input voltage does not match
detector output voltage.
Mobile phase contamination.
Material bleeding from column.
Leaks in system or the LightPipe
flowcell.
Tiny bubble trapped in LightPipe
flowcell.
Excessive temperature fluctuations.
Remedy
Flush the flowcell with cleaning solvents (see
"Cleaning the LightPipe Flowcell"
Check for leaks.
Check all the fittings from the column outlet to
the flowcell inlet for leaks.
Increase the flow rate until you remove the
bubble. Connect a backpressure device to the
flowcell outlet (check the pressure rating to avoid
rupturing the flowcell).
Replace the flowcell.
Allow a 30 minute warm-up for normal
operation and a 1½ hour warm-up for maximum
sensitivity.
Replace the lamp.
Check the cable connections to the detector
output; do not ground at both ends of cable.
Clean the dirty component.
Verify that the integrator is connected to the
appropriate Analog Output connections on the
back panel of the detector. (See
"Installation." ) Check the attenuation setting on
integrator.
Flush the flowcell with cleaning solvents as
described in "Cleaning the LightPipe Flowcell"
on page 85. Check for leaks.
Replace the mobile phase with fresh mobile
phase that is made with high-purity solvents.
Clean or replace the column.
Check all the fittings for leaks. Replace the
flowcell.
Increase the flow rate until you remove the
bubble. Connect a backpressure device to the
flowcell outlet (check the backpressure rating to
avoid rupturing the flowcell).
Remove the system from drafts. Thermostatically
control the column temperature.
on page 85).
Chapter 2,
Thermo Scientific