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Diagnostics and Calibration
2
2.2 User-Initiated Diagnostics
There are two types of user-initiated PDA diagnostic tests:
• Internal Tests – Tests run by the instrument firmware that help you determine the
source of a malfunction. These tests do not require connections to external devices.
• Interactive Tests – Tests that check analog output and event input/output signal
communications between the detector and connected external devices. These tests
require connections to pump flow and/or test equipment.
Note:
You cannot perform diagnostics on a 996 detector while it is acquiring data.
Note:
The system administrator can restrict access to the 996 detector diagnostics by
disabling user access to Quick Set. For details, refer to the “User Type Properties Dialog
Box” topic in the Millennium
32
Online Help Find tab.
Change in reference
spectrum
Mobile phase
contains gas or is
contaminated.
Prepare fresh mobile phase and
degas thoroughly.
Air bubbles trapped in
flow cell.
Flush the flow cell, or apply slight
backpressure on the detector waste
outlet.
To prevent air bubbles, check that
there is a 1- to 2-foot (30- to 60-cm)
length of 0.009-inch (0.23-mm) I.D.
tubing connected to the detector
waste outlet.
Solvent in drain line
Leak from flow cell
gasket.
Rebuild flow cell with a new gasket
(see
Section 3.1.3, Disassembling and
).
Leak from flow cell
fittings.
Check fittings for overtightening or
undertightening, and replace fittings if
necessary.
Table 2-1 996 Detector Troubleshooting (Continued)
Symptom
Possible Cause
Corrective Action
