Agilent Technologies 7890A Manual

Agilent Technologies
Replacing the NPD Bead
Instruction Guide
NPD Bead Replacement.book Page 1 Monday, October 13, 2008 2:32 PM

2Instruction Guide
Notices
© Agilent Technologies, Inc. 2008
No part of this manual may be reproduced in
any form or by any means (including elec-
tronic storage and retrieval or translation
into a foreign language) without prior agree-
ment and written consent from Agilent
Technologies, Inc. as governed by United
States and international copyright laws.
Manual Part Number
G3430-90037
Edition
Third Edition, October 2008
Second Edition, September 2008
First Edition, March 2004
Printed in USA
Agilent Technologies, Inc.
2850 Centerville Road
Wilmington, DE 19808-1610 USA
Warranty
The material contained in this docu-
ment is provided “as is,” and is sub-
ject to being changed, without notice,
in future editions. Further, to the max-
imum extent permitted by applicable
law, Agilent disclaims all warranties,
either express or implied, with regard
to this manual and any information
contained herein, including but not
limited to the implied warranties of
merchantability and fitness for a par-
ticular purpose. Agilent shall not be
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Safety Notices
CAUTION
A CAUTION notice denotes a haz-
ard. It calls attention to an operat-
ing procedure, practice, or the like
that, if not correctly performed or
adhered to, could result in damage
to the product or loss of important
data. Do not proceed beyond a
CAUTION notice until the indicated
conditions are fully understood and
met.
WARNING
A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like that, if not correctly per-
formed or adhered to, could result
in personal injury or death. Do not
proceed beyond a WARNING
notice until the indicated condi-
tions are fully understood and
met.
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3
Replacing the NPD Bead
Instruction Guide
Agilent Technologies
Replacing the NPD Bead
7890A and 6890 Gas Chromatographs
This instruction guide reviews the procedure for installing a
bead on a nitrogen- phosphorus detector (NPD). Before
following this procedure, refer to the safety information on the
inside front cover and in your GC user information.
Parts list
•1 NPD bead assembly (ceramic or Blos)
•Cap for the bead
•Test chromatogram
NOTE If you used Blos beads before 2008, you may notice that the current bead
has a slightly different shape and color. This is normal.
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4Instruction Guide
Replacing the NPD Bead
Required tools
•T- 10 Torx screwdriver
GC Firmware
•If using a 7890A Series GC, it is recommended that the
firmware version is A.01.09 or higher.
•If using a Blos bead on a 7890A Series GC, make sure the
firmware version is A.01.09 or higher.
•If using a 6890 Series GC, make sure the firmware version is
A.03.05 or higher.
•If using a Blos bead on a 6890 Series GC, make sure the
firmware version is A.03.08 or higher. (Firmware versions
earlier than A.03.08 will immediately destroy a Blos bead if
you use the Adjust Offset feature.)
Figure 1 Blos bead assembly
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Replacing the NPD Bead
Instruction Guide 5
Preparing the GC
1 Gather the following:
•Lint- free gloves
•T- 10 Torx screwdriver
2Set the NPD bead voltage to 0.0. (Do not set it to Off.)
Agilent data system users: After setting the bead voltage to
0.0, save the data system method and shut down the
instrument session. (Note that in some data system versions,
you may need to use the GC keypad to set the voltage. To do
this, the GC keypad must be unlocked and you must close the
GC parameters screen of the data system. Upload the revised
setting, then save the method and shut down the instrument
session.)
3Set Adjust Offset to Off.
4Cool 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.
CAUTION 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.
WARNING Hazardous voltages are present when the electronics top cover is
open.
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6Instruction Guide
Replacing the NPD Bead
5Remove the necessary GC covers.
•7890A models: Raise the GC detector top cover. Loosen
the screw on the electronics top cover and lift cover
(Figure 2).
•6890 models: Gently lift the gray plastic detector top
cover (with the holes and ventilation slots).
For models with the hinge bracket: The hinge is a
metal bracket attached to the oven top. Pull the clip at its
top toward you to release the hinge pin. Push the pin to
the left to release the cover. Raise the cover and remove it.
Remove the top electronics cover. Push the clips
underneath the cover (shown in Figure 3) toward the
center to disengage them.
Figure 2 Lifting the electronics top cover (7890A)
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Replacing the NPD Bead
Instruction Guide 7
Other models: Push the clips underneath the cover toward
the center to disengage them.
Figure 3 Removing the top electronic cover (6890)
Clips
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8Instruction Guide
Replacing the NPD Bead
Removing and Installing the Bead
1Put on lint- free gloves before touching any of the detector
parts.
NOTE The illustrations below show a ceramic bead. Blos bead installation is the
same.
WARNING Be careful! The oven or detector fittings may be hot enough to cause
burns.
CAUTION Wear clean, lint-free gloves to prevent contamination of parts with dirt
and skin oils.
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Replacing the NPD Bead
Instruction Guide 9
2Twist the ring to disconnect the bead assembly cable. Push
and twist the lock so that the button slides up in the groove,
then pull the cable ends apart.
1
2
3
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10 Instruction Guide
Replacing the NPD Bead
3Remove the 3 T- 10 Torx screws from the bead assembly.
4Gently lift up and remove the old bead assembly. Avoid
bumping the bead on the sides of the collector.
5Remove the protective cap covering the new bead.
Bead assembly
NOTE For a new Blos bead, the bead should be centered as shown in Figure 1. If
you notice that the bead assembly does not appear like the assembly
shown in Figure 1, carefully center the bead. Be sure to not contaminate
the bead during this process.
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