INFICON Cool Drawer Single Sensor - Manual (Page 41)

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Cool Drawer Single and Dual Sensors Operating Manual
Chapter 4
Troubleshooting and Maintenance
4.1 Troubleshooting Guide
If the Cool Drawer sensor fails to function, or appears to have diminished
performance, the following Symptom, Cause, Remedy Table in
section 4.2 on
page 4-5 may be helpful.
4.1.1 Troubleshooting
A useful tool for diagnosing sensor head problems is the DMM (Digital MultiMeter).
Disconnect the short oscillator cable from the feedthrough and measure the
resistance from the center pin to ground.
 If the reading is less than 10 megohms the source of the leakage should be
found and corrected.
 With the vacuum system open, check for center conductor continuity, a reading
of more than 1

from the feedthrough to the transducer contact indicates a
problem. Cleaning contacts may be required.
Another useful diagnostic is to continuity-test the sensor head without a crystal.
Remove the Cool Drawer from the sensor body. The DMM should measure 1
 or
less from the center pin of the feedthrough to ground, see Figure 4-1 . Reforming
the leaf springs may be required if the reading is incorrect.
Figure 4-1 Center conductor continuity