Maintaining the FPD
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12
Maintaining Your GC 241
To Change the FPD
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Wavelength Filter
1 Gather the following:
• Sulfur filter with filter spacer (See “Consumables and
Parts for the FPD
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on page 234.)
• Phosphorus filter
• Cotton swab
• Lens tissue
• Lint-free gloves
2 Load the GC maintenance method and wait for the GC to
become ready.
3 Turn off the photomultiplier tube (PMT).
a Select [Front Det] or [Back Det].
b Scroll to PMT voltage.
c Press Off.
4 Disconnect the retaining spring that holds the PMT assembly
to the bracket. With a rotating motion, pull the assembly
away from the filter housing.
CAUTION
Do not touch the filter with your bare hands. For optimum
performance and to avoid scratches, use lint-free gloves for
assembling and inserting the filter into the assembly.
WARNING
Be careful! The detector may be hot enough to cause burns. If the
detector is hot, wear heat-resistant gloves to protect your hands.
CAUTION
The photomultiplier tube (PMT) is extremely sensitive to light.
Always turn off the electrometer (which turns off the high voltage to
the PMT) before removing the PMT housing or opening the
emissions chamber. Failing to do this can destroy the PMT.
Even with the electrometer off, protect the PMT from room light.
Cap the housing after it is removed, place it end down to exclude
light, or reduce the room light level before exposing the PMT. A brief
exposure (always with the electrometer turned off) will not damage
it, but prolonged exposure will cause a gradual loss of sensitivity.