7 General Maintenance
To Close the Analyzer Chamber
220 5977B 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 “To Connect/Disconnect
Wiring from the EI XTR, SS, and Inert Sources” on page 197.)
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 MSD Troubleshooting and
Maintenance Manual 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 “To Pumpdown the MSD” on page 139.)
6 Once the MSD has pumped down, close the left analyzer cover and replace
the window cover.
7 Tune the MSD.
Do not force the analyzer door when closing, or you may damage the
quadrupole.
The top thumbscrew must be fastened if hydrogen (or other hazardous gas) is
being used as the GC carrier gas or if hydrogen is used for the JetClean
system. In the unlikely event of an explosion, it may prevent the side plate
from opening.
Do not overtighten the thumbscrew; it can cause air leaks or prevent
successful pumpdown. Do not use a screwdriver to tighten the thumbscrew.