HP 5973 MSD, Hardware Manual

Page: 83 / 122

Troubleshooting
1RRUORZ3)'7'VLJQDOEXWUHDJHQWLRQVDUHQRUPDO
83
No or low PFDTD signal, but reagent ions are normal
Possible Cause You are flowing any reagent gas but methane in PCI.
Action Switch to methane.
Possible Cause
Wrong or corrupted tune file loaded.
Action
Check your tune file.
Possible Cause No PFDTD in the calibrant vial.
Action Inspect the calibration vial on the back of the flow controller. If necessary, fill the
vial with PFDTD. Do not fill the vial completely; keep the level at least 0.5 cm from
the top of the vial.
Possible Cause
The pressure of the methane entering the flow controller is too high.
Action Make sure the regulator on the methane supply is set to 10 psig (70 kPa).
Possible Cause
The CI ion source is dirty.
Action
Clean the ion source. See the Maintenance chapter in this manual for more
information.
Possible Cause The calibration valve was not purged after the vial was refilled.
Action Purge the calibration valve as described in the Maintenance chapter. Then clean
the ion source.
Possible Cause
The calibrant vial was overfilled. Excess PFDTD can quench the chemical ionization
reactions.
Action Check the level of the PFDTD in the calibration vial as described in Maintenance
chapter.