Agilent Technologies 6890 Series, Руководство по обслуживанию, Страница: 322 / 867

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Jun 2001
Detectors
Agilent 6890 Gas Chromatograph Service Manual
Micro-cell Electron Capture Detector (
µ
-ECD) 341
Replacement procedures
• The end of the column does not protrude from the top of the makeup
gas adapter. For most columns (outer diameter > 0.15 mm), insert
the column as far as it will go into the gigabore liner. If using a
microbore column that passes completely through the liner, position
the column so that the total length from the back of the capillary nut
to the end of the column is about 70 to 72 mm.
Removing an EPC flow manifold
Early models of the 6890 GC used Type 1 EPC flow manifolds. Later models
use Type 2 manifolds. Both types are covered here.
The
µ
-ECD detector EPC flow manifold contains one inlet supply fitting for
a purge/make-up gas.
WARNING Before proceeding, turn off the oven and any heated zones and let them cool
down. Turn off any detector gases at their supply, then turn off the main
power switch and unplug the power cord.
1. Remove the top plastic covers from the detector and pneumatics areas.
Also remove the RFI metal shield and the top rear metal cover.
2. Remove the gas supply fitting from the side (Type 1) or rear (Type 2) of
the manifold.
3. At the front of the manifold, remove the Torx T-20 screw that holds the
manifold in its slot.
4. Disengage the detector tubing from the slots in the chassis so that the
gang fitting on the manifold can be removed easily.
Caution Make sure you are properly grounded with an ESD strap before continuing.
5. Unlock the detector manifold’s ribbon cable from the EPC board and
detach the connector. The adjacent ribbon cable may have to be removed
as well.