Models 947, 948 and 960 Leak Detectors Operations and Service Manual
4-17
Use new O-rings wiped clean with a lint-free cloth. Do
not apply vacuum grease to O-rings that come in
contact with the spectrometer tube.
4.2.5.3 Spectrometer Tube Cleaning
To clean the spectrometer tube:
1. Use the Scotch-Brite
™
flexible abrasive pads from the spectrometer cleaning kit to
remove heavy deposits from the ground slit plate, and spectrometer tube body.
2. Wipe all parts with VacuSolv wipes.
3. Allow parts to air dry thoroughly.
4.2.5.4 Reassembly of the Spectrometer Tube and Preamplifier
To reassemble the spectrometer tube:
Refer to Figure 4-4 for step 1 through step 5, to Figure 4-5 for step 6 through step 8, and
Figure 4-6 on page 4-20 for step 9 through step 13.
1. Place a new metal seal
➀
on the collector housing assembly
➁
with the ends of the seal
crossed under one of the screw holes (Figure 4-4, View A).
2. Mount the collector housing assembly to the spectrometer tube body
➂
with the four
socket head cap screws, sized 8-32.
3. Tighten all four screws in an opposing sequence until a 0.007" clearance is attained
between the collector housing assembly and the spectrometer tube body.
Use a feeler gauge to measure the clearance and another leak detector (if available) to
leak check to 1 x 10
−
9
atm cc/sec.
4. The preamplifier
➃
, connector bracket, and collector housing assembly that came off as
one unit can now be reattached to the spectrometer tube body by replacing the screw at
the base of the connector bracket.
5. Replace the preamplifier cover
➄
and the five Phillips head screws that hold it in place.
