Edwards APGX-H, Instruction Manual, Page: 23 / 32

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Maintenance
D023-92-880 Issue F
Figure 6 - Replace the APGX-H Tube
5.4 Fault finding
Table 3 - Fault Finding Information
5.5 Calibration service
A calibration service is available for all Edwards gauges. Calibration is by comparison with reference gauges,
traceable to National Standards. Contact Edwards for details.
1. Tube securing screws
Symptom Remedy
The indicated pressure is
incorrect Check the electrical connections and ensure that the electrical
supply is correct. Perform the atmosphere and vacuum
adjustment described in
Section 5.1 . If this fails to solve the
problem, you will need to replace the tube. Refer to Section 7.2 .
Gauge indicates calibration error Check the electrical connections and ensure pin 7 is not connected
to 0 V. If this fails to solve the problem:

Adjustment has been performed at an inappropriate
pressure; repeat the adjustment referring to
Section 5.1 .

The tube has drifted outside permissible limits and the
gauge can no longer measure pressure accurately. You will
need to replace the tube. Refer to
Section 7.2 .
Gauge indicates broken filament The filament has broken and the gauge can no longer measure
pressure. You will need to replace the tube. Refer to Section 7.2 .
Gauge indicates tube
disconnected Ensure that the tube is plugged into the electronics housing. If
this fails to solve the problem the gauge is faulty and should be
replaced.
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