Agilent Technologies G3375A Instruction Manual

This section reviews the procedure for installing a single-channel analog
input board (AIB) on an Agilent 6850 Gas Chromatograph (hereafter called
the GC.) With the analog board installed, you can connect nonAgilent
detectors with 1 V of analog output to the GC.
This kit contains:
Description Quantity Part number
Grommet 10400-0914
Screw, M3 × 0.5, 12-mm long, pan head 10515-1084
Torx™screw, M4 × 18-mm long 20515-3034
Screw, M4 × 0.7, 12-mm long 20515-2496
Analog signal cable, general purpose, 6 pins 1G1530-60560
Analog input board 1G1556-60015
Detector PCB bracket 1G2397-00020
Insulation detector blank 1G1530-00660
MS detector plate 1G2630-20980
Installing a Single-Channel
Agilent 6850 Series II Network GC System
Analog Input Board on a 6850 GC
Accessory G3375A

2
Installing a Single-Channel Analog Input Board on a 6850 GC
Required tools
• Electrostatic protection such as grounded wrist strap
(part no. 9300-0969 [large] or part no. 9300-0970 [small])
• T-20 Torx screwdriver
• Small, flat-bladed screwdriver
• 1/8-inch drill bit and drill
Overview
Caution Before starting, review the safety information listed at the end of this
document.
1. Prepare the GC.
2. Remove the lid top cover.
3. Remove the existing detector and flow manifold.
4. Raise the lid to the service position.
5. Remove existing detector PC board.
6. Position the analog cable.
7. Install the AIB.
8. Install the insulation detector blank and detector plate.
9. Connect the analog signal cable to your nonAgilent detector.
10. Restore the GC to operating condition.

Installing a Single-Channel Analog Input Board on a 6850 GC
3
Prepare the GC
1. Load the service method or set all GC temperatures to ambient/35 °C.
2. Allow time for all heated zones to cool.
3. Turn off the GC and unplug the power cord.
4. If you have an injector installed, set it aside.
Remove the lid top cover
Remove T-20 Torx
screws (8 places)
Remove detector
cover, if desired
Remove vent tubing,
if present

4
Installing a Single-Channel Analog Input Board on a 6850 GC
Remove the existing detector and flow manifold
1. On the top of the lid, loosen the connector cover plate screws and
remove the plate.
2. Disconnect the gas fittings. The figure shows the µECD manifold; the
other manifolds are similar but vary in the number of gas connections.
3. Trace the ribbon cable from the flow manifold and disconnect it from
the harness.
4. Remove the three manifold mounting screws.
5. Remove the screws holding the detector assembly in place. You will
need a new top cover.
FID (flame ionization detector) – Remove four mounting screws.
Flow manifold
( µ ECD shown)
Gas fittings
Cover plate
screws (4)
Manifold mounting
screws
Mounting screws

Installing a Single-Channel Analog Input Board on a 6850 GC
5
TCD (thermal conductivity detector) – Remove two mounting screws.
µECD (micro cell electron capture detector) - Remove four mounting
screws.
FPD (flame photometric detector) - Remove four mounting screws. You
will need a new top cover.
6. Lift the detector and flow manifold out of the lid as a unit.
Mounting screws
Mounting screws
Two mounting
Two mounting screws
screws

6
Installing a Single-Channel Analog Input Board on a 6850 GC
WARNING The fibrous insulation material can cause irritation to the skin, eyes, and
mucous membranes. Always wear gloves when working with the insulation.
If the insulation is flaky/crumbly, wear protective eye wear and a respirator.
7. Remove any insulation that may be in the hole under the detector.
Raise the lid to the service position
1. Open the lid. Locate the counterbalance cam in the left rear corner
under the lid. Loosen the screw on the right side of the cam. This allows
the stop plate to drop down.
2. Raise the lid until it is stopped by the safety cable.
3. Raise the stop plate and tighten the screw to lock the lid in the upright
service position.
WARNING The lid is heavy. Always lock the lid when it is in the service position.
Stop plate (raised)
Counterbalance cam
Lid in service position

Installing a Single-Channel Analog Input Board on a 6850 GC
7
Remove existing detector PC board
Since there is room for only one detector on the 6850 GC, you must remove
any existing detector PC board before installing the AIB.
1. Loosen the two bottom screws on the detector electronics cover.
Caution Board compo n ents can be d amaged by stat ic electric ity; use a prope rly
grounded static control wrist strap before gaining access to the
detector electronics area and when handling the boards and any of
the cables connecting to the boards.
2. Remove the top screw on the cover.
3. Lift and remove the detector electronics cover.
Remove screw
Detector
Loosen screws
electronics
cover

8
Installing a Single-Channel Analog Input Board on a 6850 GC
4. Prepare the detector board for removal.
a. For small boards, such as the µECD shown below, remove the M3
screw that secures the detector board to the printed circuit board
(PCB) bracket.
M3 screw securing
board to bracket
Detector PCB bracket
Detector board
(µECD shown)
A/D converter board

Installing a Single-Channel Analog Input Board on a 6850 GC
9
b. For large boards, such as the FPD board shown below, remove the
detector PCB bracket holding the detector board in place.
Detector board
Detector PCB bracket
A/D converter board
(FPD shown)
mounting screw

10
Installing a Single-Channel Analog Input Board on a 6850 GC
5. Unplug and remove the existing detector board from the A/D converter
board. An FPD board is shown below. Other detector boards connect
similarly.
6. Disconnect and remove all cables from the old detector board.
All detectors – Disconnect the ribbon cable. The ribbon cable connector
will not pass through the rubber grommet in the hole. Use a small
screwdriver to push the grommet to the top of the lid; the cables will
now fit through the hole. Reinstall the grommet in the lid for later use
after you have removed the ribbon cable.
A/D converter board/
detector board connection