SRS Labs QMS 100 Series, User Manual

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Component Replacement 5-21
Technical Reference
Figure 2 Probe Removal for Ionizer Replacement
6. Carry the probe to a clean, dust free area immediately. Avoid contamination using handling
procedures compatible with high vacuum requirements.
7. Hold the probe in a upright position and do a thorough visual inspection of the unit. Check for
loose, damaged, misaligned and contaminated components.
8. Using the clean, flat-head screwdriver remove the screw that connects the repeller to the longest
filament rod and pull out the cage exposing the filament and the anode grid. Be careful not to
damage the delicate filament if you plan to use it again!
9. Remove the filament following the steps and precautions described in the “Filament
Replacement” section of this chapter.
10. Next, pull out the anode grid after removing the two screws that fasten its bottom plate to the
alignment rods. The two rods do not need to be replaced and should not be moved during this
procedure!
11. Finally, remove the two screws that hold the focus plate against the top alumina spacer and pull
out the plate. The short alignment rod will also need to be removed during this step, but it does
not need to be replaced (Save it!).
12. Use the new parts from the “Ionizer Replacement Kit” to replace the ionizer components. The
new components are clean and vacuum compatible.
Avoid contamination! Replace all
components at once! Discard the old ones!
13. Use two fresh screws from the ionizer replacement kit to mount the new focus plate on the
alumina spacer. Make sure the short alignment rod is put back in place and the screws are tight.
14. Install the new anode grid. Use the new screws to fasten its bottom plate to the alignment rods.
Caution: The anode cage is fairly strong but it should still be handled very carefully since its
correct alignment is essential for optimum performance of the RGA.
15. Once the anode grid is secured in place, replace the filament following the steps described in the
“Filament Replacement” section of this chapter.
It is highly recommended that a new
filament be used for this step since damage to the delicate thoria coating is
unavoidable during removal.