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CHAPTER 6:
Maintenance and Troubleshooting
Model CRX-6.5K Probe Station
1. Install a vacuum gauge to the available NW 25 gauge port on the vacuum cham-
ber or on the chamber side of the vacuum isolation valve. The NW 40 T from the
PS-V81DPC may be placed between the vacuum isolation valve and the chamber
as shown in section FIGURE 6-4.
2. Pump out the vacuum chamber as described in section 4.4.2.
3. Allow the pump to run for 2 h.
4. Log the gauge reading at the chamber.
5. If the system did not reach <10
-3
Torr, refer to section 6.3.1.6 to section 6.3.1.8.
6. Close the vacuum isolation valve.
7. Turn off the vacuum pump and vent the turbo.
8. Wait 10 min; compare the gauge reading at the chamber to the reading recorded
in step 4. If the reading is more than one order of magnitude above the reading
recorded in step 4, or the pressure reading continues to rise rapidly, there may be
a leak in the vacuum chamber.
6.3.1.6 Will Not Achieve 10
-2
Torr
If the system will not achieve at least 10
-2
Torr in the vacuum chamber, the problem is
likely mechanical and should be relatively easy to identify. Follow this procedure to
find the issue.
D
Open and fully close the purge valve; purge valve seats sometimes do not
fully close
D
Close the turbo vent valve if it is not closed automatically
D
Visually inspect the pressure relief valve to verify that it is properly seated
D
Check the alignment of the vacuum chamber lid
D
Verify that the chamber lid o-ring is properly seated
D
Verify that the seals and clamps are properly installed on the vacuum line
D
Examine any changes that were made to the system since it was last used to
verify that the system was reassembled properly
D
Look for any parts that may have been damaged, including bellows, vacuum line,
valves, fittings, etc.
6.3.1.7 Will Not Achieve 10
-3
Torr
Systems achieving between 10
-2
Torr and 10
-3
Torr in the vacuum chamber can be
more difficult to troubleshoot because these smaller leaks can be hidden.
D
Examine any changes that were made to the system since it was last used
(especially removal of probe arm assemblies) to verify that the system was
reassembled properly. Remove, clean, inspect for damage, grease, and reinstall
o-rings that were used in the change.
FIGURE 6-4
Vacuum gauge on the Model CRX-6.5K
vacuum chamber