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Table of Contents Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 15
13.2.2. Typical Sample Gas Flow Problems ..................................................................................................282
13.2.2.1. Flow is Zero ................................................................................................................................282
13.2.2.2. Low Flow ....................................................................................................................................282
13.2.2.3. High Flow ....................................................................................................................................282
13.2.2.4. Displayed Flow = “Warnings” .....................................................................................................283
13.2.2.5. Actual Flow Does Not Match Displayed Flow ............................................................................283
13.2.2.6. Sample Pump .............................................................................................................................283
13.3. Calibration Problems .................................................................................................................................283
13.3.1. Miscalibrated ......................................................................................................................................283
13.3.2. Non-Repeatable Zero and Span ........................................................................................................284
13.3.3. Inability to Span – No SPAN Key .......................................................................................................284
13.3.4. Inability to Zero – No ZERO Key .......................................................................................................284
13.4. Other Performance Problems ...................................................................................................................285
13.4.1. Temperature Problems ......................................................................................................................285
13.4.1.1. Box or Sample Temperature ......................................................................................................285
13.4.1.2. Bench Temperature ....................................................................................................................285
13.4.1.3. GFC Wheel Temperature ...........................................................................................................286
13.4.1.4. IR Photo-Detector TEC Temperature .........................................................................................286
13.4.2. Excessive Noise .................................................................................................................................287
13.5. Subsystem Checkout ................................................................................................................................288
13.5.1. AC Mains Configuration .....................................................................................................................288
13.5.2. DC Power Supply ...............................................................................................................................288
13.5.3. I
2
C Bus ...............................................................................................................................................289
13.5.4. Keyboard/Display Interface ................................................................................................................289
13.5.5. Relay Board .......................................................................................................................................290
13.5.6. Sensor Assembly ...............................................................................................................................291
13.5.6.1. Sync/Demodulator Assembly .....................................................................................................291
13.5.6.2. Electrical Test .............................................................................................................................291
13.5.6.3. Opto Pickup Assembly ...............................................................................................................292
13.5.6.4. GFC Wheel Drive .......................................................................................................................292
13.5.6.5. IR Source ....................................................................................................................................292
13.5.6.6. Pressure/Flow Sensor Assembly ...............................................................................................293
13.5.7. Motherboard .......................................................................................................................................294
13.5.7.1. A/D Functions .............................................................................................................................294
13.5.7.2. Test Channel / Analog Outputs Voltage .....................................................................................294
13.5.7.3. Analog Outputs: Current Loop ....................................................................................................295
13.5.7.4. Status Outputs ............................................................................................................................296
13.5.7.5. Control Inputs – Remote Zero, Span ..........................................................................................297
13.5.8. CPU ....................................................................................................................................................297
13.5.9. RS-232 Communications ...................................................................................................................297
13.5.9.1. General RS-232 Troubleshooting ...............................................................................................297
13.5.9.2. Troubleshooting Analyzer/Modem or Terminal Operation .........................................................298
13.5.10. The Optional CO
2
Sensor ................................................................................................................298
13.6. Repair Procedures ....................................................................................................................................299
13.6.1. Repairing Sample Flow Control Assembly ........................................................................................299
13.6.2. Removing/Replacing the GFC Wheel ................................................................................................300
13.6.3. Checking and Adjusting the Sync/Demodulator, Circuit Gain (CO MEAS) ......................................302
13.6.3.1. Checking the Sync/Demodulator Circuit Gain ............................................................................302
13.6.3.2. Adjusting the Sync/Demodulator, Circuit Gain ...........................................................................303
13.6.4. Disk-On-Module Replacement Procedure .........................................................................................304
13.7. Technical Assistance ................................................................................................................................304
14. A PRIMER ON ELECTRO-STATIC DISCHARGE ......................................................... 305
14.1. How Static Charges are Created ..............................................................................................................305
14.2. How Electro-Static Charges Cause Damage ............................................................................................306
14.3. Common Myths About ESD Damage .......................................................................................................307
14.4. Basic Principles of Static Control ..............................................................................................................307
14.4.1. General Rules ....................................................................................................................................307
14.4.2. Basic anti-ESD Procedures for Analyzer Repair and Maintenance ..................................................309