5
General Maintenance
162
5975/5977 Series MSD Operating Manual
To Close the Analyzer Chamber
Procedure
1
Ensure all the internal analyzer electrical leads are correctly attached. Wiring
is not the same for both the EI and CI sources. (See
Wiring from the EI XTR, SS, and Inert Sources”
Check the side plate O-ring.
Make sure the O-ring has a
very
light coat of Apiezon L high vacuum
grease. If the O-ring is very dry, it may not seal well. If the O-ring looks shiny,
it has too much grease on it. Refer to the
5977 Series MS Troubleshooting
for lubricating instructions.
2
Swing the analyzer side plate closed.
3
Ensure the vent valve is closed.
4
If hydrogen or other flammable or toxic substance is used for carrier gas,
gently
hand-tighten the top thumbscrew on the analyzer side plate.
5
Pumpdown the MSD. (See
6
Once the MSD has pumped down, close the left analyzer cover and replace
the window cover.
7
Tune the MSD.
CAUTION
Do not force the analyzer door when closing, or you may damage the
quadrupole.
WARNING
The top thumbscrew must be fastened if hydrogen (or other hazardous gas) is
being used as the GC carrier gas. In the unlikely event of an explosion, it may
prevent the side plate from opening.
CAUTION
Do not overtighten the thumbscrew; it can cause air leaks or prevent
successful pumpdown. Do not use a screwdriver to tighten the thumbscrew.