Varian 4000 GC, Hardware Operation Manual

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Troubleshooting
How to Isolate a GC/MS Problem
In general, whenever you attempt to isolate a 4000 MS problem, you will check
the system in the following order:
•
Data System
•
Gas Chromatograph
•
Mass Spectrometer
Checking the Data System
Please refer to the 4000 MS software release notes for relevant software
troubleshooting procedures.
Checking the GC
The simplest and most effective way of isolating a GC problem is to run a test
sample. Running a sample will allow you to check several operational and
performance factors, including the carrier gas supply, chromatographic
characteristics, and sample-related problems.
The test sample that is most frequently run is the COLTEST mixture. This
multiple component mixture is very well suited to troubleshooting injector and
column problems. Please see “Running the COLTEST Sample” on page 109 for
a description on the use of this test mixture.
To identify the source of a GC electronics problem, press the STATUS key and a
CONTROL key, (i.e., injector, column oven, etc.), to determine if a fault is
present. If a fault is present, the message FAULTED appears. Consult the 3800
GC manuals for information about fixing GC faults. Make sure that you are
thoroughly familiar with all safety issues before you attempt to repair any
electronics component.
Checking the Mass Spectrometer
If your data system and GC are operating normally, the problem could be caused
by the mass spectrometer or by the communication channel between it and the
data system. Typical problems with the ion trap include lack of response (no
spectra), low response, poor resolution, and mass mis-assignment.
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