To Replace The Npd Bead Assembly - Agilent Technologies 7820A Manual

To Replace the NPD Bead Assembly

C AU TI O N
WA RN IN G
WA RN IN G
Maintaining Your GC
Gather the following:
1
• Replacement NPD bead assembly. (See
Parts for the NPD"
• Lint-free gloves
• T-10 Torx screwdriver
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.
2 Using the Software Keypad or data system, set the NPD bead
voltage to 0.0, then turn it off. (Setting the bead voltage to
zero first makes sure that when you turn the bead back on,
the voltage is safe. Otherwise, turning off the bead voltage
will save a high setpoint that can damage a new bead.)
Agilent data system users: After setting the bead voltage to
0.0, save the data system method and shut down the
instrument session.
Set Adjust Offset to Off.
3
4 Cool the detector to 60 °C or lower. Leave all gas flows on. To
cool the detector faster, raise the GC detector cover and open
the hinged NPD cover.
Remove the GC detector top cover.
5
Hazardous voltages are present when the electronics top cover is
open.
Remove the electronics cover. See
6
Electronics Cover".
Put on lint-free gloves before touching any of the detector
7
parts.
Be careful! The oven or detector fittings may be hot enough to
cause burns.
Maintaining the NPD
"Consumables and
on page 208.)
"To Remove the
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