Models 947, 948 and 960 Leak Detectors Operations and Service Manual
4-22
4.2.7 Spectrometer Tube Exchange
The spectrometer tube replaceable parts consist chiefly of the ion source, the preamplifier,
the magnetic poles, and the spectrometer tube as a complete assembly.
NOTE
Because of the complexity and sensitivity of the preamplifier,
Varian recommends replacing the entire spectrometer tube if
the preamplifier must be replaced.
Rebuilt spectrometer tubes are available from Varian Vacuum
Technologies on an exchange basis. Contact Varian Vacuum
Technologies Customer Service at 1-800-8VARIAN for details.
Replacement of the ion source or preamplifier requires removal of the spectrometer tube.
Complete overhaul of the spectrometer tube includes complete disassembly of the
spectrometer tube including replacing the ion source and preamplifier. Both procedures
require that calibration, tuning and leak checking be performed prior to using the
947/948/960 for testing.
CAUTION
Use powder-free butyl or polycarbonate gloves to prevent skin
oils from getting on vacuum surfaces.
The preamplifier is a static sensitive device. Wear a grounding
device while the preamplifier is being handled.
WARNING
Store the Ion Source in a cool, dry area in a tightly sealed
container. When handling the Ion Source, wear powder-free
butyl or polycarbonate gloves. If you handle the Ion Source
with bare hands, wash them thoroughly and especially before
smoking or eating.
4.2.7.1 Removing and Replacing both the Spectrometer Tube Assembly and Preamplifier
Refer to “Disassembly of the Spectrometer Tube and Preamplifier” on page 4-15.
4.2.7.2 Reinstalling the Spectrometer Tube
To perform this procedure:
1. Using a VacuSolv wipe, clean the SVBA flange and allow it to air dry completely.
2. Place the clean, new, ungreased centering ring and O-ring on the vacuum flange of the
spectrometer tube.
CAUTION
Do not use grease or other substances on O-rings that come in
contact with the spectrometer tube.
Wipe all O-rings clean with a lint-free cloth before installation
to ensure that no foreign matter is present to impair the seal.
