INFICON Front Load Single Sensor - Manual (Page 80)

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Front Load Single and Dual Sensors Operating Manual
5.1.2.1 Electrical Isolation Check
1 Remove the Crystal Holder from the sensor head.
2 Disconnect the short BNC cable from the feedthrough.
3 Select the DMM ohmmeter function and high resistance (MΩ) scale.
4 At the feedthrough, measure resistance between center contact and shield of
the BNC connector (shown by
Figure 5-1 ).
 If resistance is more than 10 MΩ, electrical isolation is good. Go to section
5.1.2.2, Electrical Continuity Check, on page 5-6 .
 If resistance is less than 10 MΩ, continue to step 5.
Figure 5-1 Resistance check
5 Disconnect the in-vacuum cable from the sensor head.
6 Measure resistance between center contact and shield of the BNC.
 If resistance is less than 10 MΩ, continue to step 7.
 If resistance is more than 10 MΩ, continue to step 6a.
6a Measure resistance between the center contact and threads of the coaxial
connector on the sensor head (shown by
Figure 5-2 ). If resistance across the
coaxial connector is less than 10 MΩ, examine the sensor head cavity and
coaxial connector for the cause of the low resistance. Contact INFICON if
cause of low resistance is not found (refer to
section 1.3, How to Contact
INFICON, on page 1-2 ).