Reinstallation - HP 5890 Series II Plus Reference Manual

Preventive Maintenance
Nitrogen-phosphorus detector (NPD)

Reinstallation

1. Reinstall the jet in the detector base (using a 1/4•inchnut driver).
Make sure that the threads are clean and free of burrs that could
cause damage. If there is any binding, the cause should be
determined and corrected before proceeding. If a torque wrench is
available, no more than 1 Nm (newton meter) of torque should be
used to install a new jet.
Do not overtighten the jet! Overtightening may permanently damage
Caution
the jet, the detector base, or both.
2. Cleaning and reassembly of the collector/collector assembly is as
follows:
Do not attempt to clean out the inside of the collector by inserting
Caution
objects such as wires or brushes•to do so may damage the active
element.
186
Powdery deposits may be removed from the interior of the collector by
gently blowing out the loose material with low•pressurecompressed air
or nitrogen.
Inspect the collector assembly to make sure that the active element is
centered in the tube and is not shorted to the side and that it is
positioned horizontally.