Thermo Scientific 074114, Operator'S Manual

Page: 84 / 148

Dionex PDA Operator’s Manual
76
Doc. 065378-01 1/12
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Connect a backpressure line to the cell (see Section B.3 ). This
increases the backpressure on the cell, thereby shrinking bubbles and
allowing them to pass more easily through the cell.
•
Contaminants in flow cell
Clean the cell (see Section 5.2 ).
•
Incorrect lamp selected
If a UV wavelength is selected, make sure the deuterium lamp is on. If a
visible wavelength is selected, make sure the tungsten lamp is on. When a
lamp is on, the corresponding LED (
DEUTERIUM – UV
or
TUNGSTEN – VIS
) is
lighted.
•
Lamp needs replacement
The light output of the lamp decreases over time. The lower light output may
increase noise above an acceptable level, especially if the lamp has been in
service for more than 2000 hours. If this occurs, replace the lamp. See
Section 5.7 or Section 5.8 for instructions on replacing the deuterium lamp or
tungsten lamp, respectively.
•
Lamp incorrectly installed
Make sure that both lamps are fully seated in the optical bench. See
Section 5.7 or Section 5.8 for installation instructions for the deuterium lamp
or tungsten lamp, respectively.
•
Inappropriate reference wavelength
Select a reference wavelength in a quiet area of the spectrum where little
absorption occurs. Thermo Fisher Scientific recommends selecting a
reference wavelength below 380 nm for UV applications and above 600 nm
for visible applications. For more information, see
“Reference Wavelength”
on page 47 .
•
Bandwidth is too narrow
Select a wider bandwidth and reference bandwidth, if appropriate for the
application. For guidelines when selecting the sample and reference
bandwidths, see
“Bandwidth” on page 46 and “Reference Bandwidth” on
page 50 .