General Troubleshooting 2
5977B Series MSD Troubleshooting and Maintenance Manual 45
Mass Spectral Symptoms
This section describes symptoms you might observe in mass spectra. Some of
these symptoms will appear in the mass spectra of samples. Others you will
observe only in a tune report. Some of these symptoms have causes that can be
corrected by the operator. Others, however, require service by an Agilent
Technologies service representative.
The following symptoms listed under Chromatic symptoms also apply to mass
spectra:
• If sensativity is low
• If repeatability is poor
No peaks
• Ion source cables not connected
• Bad connections to or from the detector
• HED power supply output cable has failed
• Other electronics failure
• Incorrect tune file (inappropriate parameters)
Isotopes are missing or isotope ratios are incorrect
• Peaks are too wide or too narrow
• Scan speed is too high (scan mode)
• Dwell time is too short (SIM mode)
• Electron multiplier voltage is too high
• Repeller voltage is too high
• High background
• Dirty ion source
High background
• Pressure in the analyzer chamber is too high
• Air leak
• Contamination
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