HP 5973 MSD, Hardware Manual

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Troubleshooting
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Troubleshooting tips and tricks
The following are general rules for troubleshooting, with specific CI
examples.
Rule 1: “Look for what has been changed.”
Many problems are introduced accidentally by human actions. Every time
any system is disturbed, there is a chance of introducing a new problem.
• If the MSD was just pumped down, suspect air leaks or incorrect assembly.
• If the reagent gas bottle or gas purifier were just changed, suspect leaks or
contaminated or incorrect gas.
• If the GC column was just replaced, suspect air leaks or contaminated or
bleeding column.
• If you have just switched ion polarity or reagent gas, suspect the tune file you
have loaded in memory -- is it the appropriate file for your mode of operation?
Rule 2: “If complex isn’t working, go back to simple .”
A complex task is not only more difficult to perform, but also more difficult
to troubleshoot as well. For example, CI requires more parts to work
correctly than EI does, and all those additional parts
• If you’re having trouble with NCI, verify that PCI still works.
• If you’re having trouble with other reagent gases, verify that methane still works.
• If you’re having trouble with CI, verify that EI still works.
Rule 3: “Divide and conquer.”
This technique is known as “half-split” troubleshooting. If you can isolate
the problem to only part of the system, it is much easier to locate.
• To isolate an air leak, start by shutting the gas select valve while leaving the
isolation valve and MFC open (turn on
Purge and Gas Off .) If abundance of m/z 32
decreases, the problem is “upstream” of the flow module.