Varian 990 dCLD II, Operation Manual

Page: 97 / 162

Model 990 dCLD II Component Leak Detector
5-3
For simplicity, the maintenance functions in this section are grouped by recommended
frequency, as shown in Table 5-1, based on assumed everyday use.
These functions can be carried out at routine intervals, as indicated. The 990 dDLD II must
be calibrated to verify sensitivity at least once a day. However, other functions may be car-
ried out either more or less often, depending on the frequency of use.
Maintenance functions that may be required on a demand basis, for example, changing an
Ion Source after filament failure, are listed in Table 5-2.
Table 5-1 Scheduled Maintenance
Description Daily 12 Months Refer to
Calibration check
X
Section 5.1 “Daily
Maintenance” on page 5-4
Recalibrate the internal calibrated leak
X
Section 5.2 “Recalibrate
the Internal Calibrated
Leak” on page 5-5
Spectrometer tube overhaul
X
Section 5.3 “Spectrometer
Tube Overhaul” on
page 5-5
Dual air intake filter replacement
X
Section 5.4 “Dual Air
Intake Filter Replacement”
on page 5-18
Table 5-2 As-required Maintenance
Function Most Common Symptom Refer to
Spectrometer tube cleaning Loss of sensitivity, increase in background,
high ion voltage (> 300 VDC), required to tune
the leak detector. Section 5.3 “Spectrometer
Tube Overhaul” on
page 5-5
Ion source replacement Filament failure (as soon as convenient after
second filament is in use). Section 5.5 “Ion Source
Replacement Outside of
Spectrometer Tube Overh
aul” on page 5-19
Tuning adjustments Use of a calibrated leak in the field other than
the one tested at the factory, or if calibration is
not successful. Section 5.6 “Manual
Tuning” on page 5-20