No Or Low Pfdtd Signal, But Reagent Ions Are Normal - HP 5973 MSD Hardware Manual

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.
1R RU ORZ 3)'7' VLJQDO EXW UHDJHQW LRQV DUH QRUPDO
 Troubleshooting
83