Model 979 Series Helium Mass Spectrometer Leak Detector
4-20
DRAFT 9/15/03
4.4 Ion Source Replacement Outside of Annual Maintenance
The ion source has two filaments. The spare is automatically turned on when Filament 1
burns out, or manually by touching the filament selector box located on the MANUAL
SPECTUBE TUNING screen (Figure 3-5 on page 3-4). Calibration may be necessary to
obtain maximum sensitivity after changing filaments. It is recommended that the ion source
be replaced as soon as convenient after the spare filament has been put into use. Replace-
ment takes about 3 minutes.
WARNING
Store the Ion Source in a cool, dry area in a tightly sealed
container. Wash hands thoroughly after handling the Ion Source
and especially before smoking or eating.
CAUTION
Use powder-free butyl or polycarbonate gloves to prevent skin
oils from getting on vacuum surfaces.
Tools
: Phillips screwdriver
Parts
: Ion Source
1. Turn off the main power switch located on the back of the 979 leak detector.
2. Remove the 2 Phillips screws from the front panel of the leak detector and drop the top
of the front panel down (Figure 4-1 on page 4-6). Be careful not to place tension on the
PCB harness.
3. Remove the ion source connector at the spectrometer tube.
4. Vent the spectrometer tube by turning the knurled nut on the turbo pump 1/4 turn
counterclockwise.
5. Remove the 4 Phillips screws that secure the ion source header (Figure 4-9 on
page 4-11).
6. Remove the ion source header by pressing down on the center post and lifting the
header up and off of the ion source.
Summary of Contents for 979 Series
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