Agilent Technologies 6890 Series Service Manual page 11

Contents
330 Thermal Conductivity Detector (TCD)
Theory of operation.................................................................................... 1
Delta PRT ............................................................................................. 3
Error messages.................................................................................... 4
EPC detector ....................................................................................... 5
Manually controlled detector ............................................................ 5
Replacement procedures ........................................................................... 7
Replacing the entire detector ............................................................ 7
Replacing the detector cell .............................................................. 10
Removing an EPC flow manifold .................................................... 13
Installing a Type 2 manifold ............................................................ 15
Replacing the detector interface card ............................................ 21
Cleaning the Thermal Conductivity Detector ....................................... 23
340 Electron Capture Detector (ECD)
Theory of operation.................................................................................... 1
EPC detector ....................................................................................... 2
Manually controlled detector ............................................................ 2
Replacement procedures ........................................................................... 4
Replacing the entire detector/detector cell ..................................... 4
Replacing the heater/sensor assembly ............................................. 8
Replacing the makeup gas adapter................................................. 10
Removing the EPC flow manifold................................................... 11
Removing the signal board .............................................................. 14
Replacing the detector interface card ............................................ 16
Diagnostics ................................................................................................ 17
Frequency test ................................................................................... 17
Leak test ............................................................................................. 18
Troubleshooting contamination problems ............................................ 20
Ensure clean gas supplies................................................................ 20
Isolate problem to carrier or makeup gas supplies ...................... 20
Evaluate the makeup side ................................................................ 21
Evaluate the carrier side .................................................................. 22
Maintaining an ECD detector .................................................................. 23
ECD bakeout ..................................................................................... 23
Performing a radioactivity leak test (wipe test) ........................... 24
8 of 24
Contents
Agilent 6890 Gas Chromatograph Service Manual
Jun 2001