Agilent Technologies Agilent 7890 Series, Maintenance Manual

Page: 279 / 354

Maintaining the NPD
14
Maintaining Your GC 279
To Maintain the NPD Collector, Ceramic Insulators, and Jet
When replacing the jet, always install a new collector,
ceramic insulators, and metal C- rings.
When replacing the collector, Agilent recommends replacing
the ceramic insulators and metal C- rings.
1
Gather the following:
• NPD ceramic insulator kit (see “Consumables and Parts
for the NPD” on page 260.)
• Collector
• Cap for the bead
• T- 10 and T- 20 Torx screwdrivers
• Tweezers
• Cotton swab
• Solvent
• Methanol
• Jet (see “Selecting an NPD Jet” on page 264)
• Lint- free gloves
• Compressed, filtered dry air or nitrogen
2 Set the bead voltage to
0.0
and
Adjust Offset
to
Off
.
3 Check and note the NPD leakage current for reference.
(See
“To Check the NPD Leakage Current” on page 285.)
4
Load the GC maintenance method and wait for the GC to
become ready.
5 Remove the bead. (See “To Replace the NPD Bead
Assembly” on page 272.)
C A U T I O N
The bead is delicate. Be careful not to break or crack the bead.
When performing maintenance on the NPD, avoid touching the bead
with your fingers, and prevent it from coming in contact with other
surfaces.
WA R N I N G
Be careful! The oven or detector fittings may be hot enough to
cause burns.