LRS Micro-g LaCoste FG5, Manual, Page: 58 / 149

Adjustment and Maintenance
4
chamber cover. Remove the six screws holding the chamber cover and handles
to the service ring, and carefully lift the cover up over the dropping mechanism.
Be sure to protect the O-ring surface on the exposed bottom flange of the
chamber cover, and keep the flange clean.
Note that whenever the chamber is vented to atmosphere, it is a good
opportunity to clean the bottom window of the chamber. It is normal, as the test
mass balls and vees wear, for the window to collect a fine dust of tungsten.
With the chamber vented, but still fully assembled (i.e. cover in place, etc.), travel
lock the cart, and gently tip the chamber on its side. Remove the six Allen screws
that hold the bottom window in place, and remove the window. Clean the
window using pure alcohol and lens paper, inspect the o-ring, and reassemble
the window. Be sure to tighten the screws in a star pattern to equally distribute
the load on the o-ring.
4.1.1.2.Replacing the Dropping Chamber Cover
Inspect the chamber O-ring and sealing surfaces. Coat the O-rings with a very
light film of Apiezon L
grease (just enough to make it “shiny”), if necessary, and
re-install the chamber cover and lifting handles. Tighten the mounting screws in
a star pattern.
With the chamber cover mounted, rotate the four snubber screws on the top rod
ring out until they come in contact with the inside of the chamber cover walls.
Tighten the screws equally an additional 1/8 turn and lock in position with the
locking nuts.
Inspect the top flange O-ring and sealing surfaces. Coat the O-rings with a very
light film of Apiezon L
grease, if necessary, and mount the top flange to the
chamber cover.
NOTE: Whenever the chamber cover is removed or the support snubbers of the
top rod ring are adjusted, the vertical alignment of the dropping chamber must
be checked and the level bubbles on the tripod tray must be reset. See the section
on “Leveling the Dropper”.
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