Model GFC7000E Instruction Manual GFC7000E Documentation
04584 Rev A1 vi
11.2.2. Non-Repeatable Zero and Span..................................................................................... 195
11.2.3. Inability to Span – No SPAN Key....................................................................................196
11.2.4. Inability to Zero – No ZERO Key.................................................................................... 196
11.3. Other Performance Problems............................................................................................... 196
11.3.1. Temperature Problems................................................................................................. 197
11.3.1.1. Box or Sample Temperature................................................................................... 197
11.3.1.2. Bench Temperature...............................................................................................197
11.3.1.3. GFC Wheel Temperature........................................................................................ 198
11.3.1.4. IR Photo-Detector TEC Temperature........................................................................ 198
11.3.2. Excessive Noise...........................................................................................................198
11.4. Subsystem Checkout..........................................................................................................199
11.4.1. AC Mains Configuration................................................................................................ 199
11.4.2. DC Power Supply.........................................................................................................200
11.4.3. I2C Bus...................................................................................................................... 200
11.4.4. Keyboard/Display Interface...........................................................................................201
11.4.5. Relay Board................................................................................................................201
11.4.6. Sensor Assembly.........................................................................................................202
11.4.6.1. Sync/Demodulator Assembly.................................................................................. 202
11.4.6.2. Opto Pickup Assembly ...........................................................................................202
11.4.6.3. GFC Wheel Drive...................................................................................................203
11.4.6.4. IR Source ............................................................................................................ 203
11.4.6.5. Pressure/Flow Sensor Assembly.............................................................................. 203
11.4.7. Motherboard...............................................................................................................204
11.4.7.1. A/D Functions.......................................................................................................204
11.4.7.2. Analog Outputs: Voltage........................................................................................ 204
11.4.7.3. Analog Outputs: Current Loop.................................................................................204
11.4.7.4. Status Outputs..................................................................................................... 205
11.4.7.5. Control Inputs – Remote Zero, Span........................................................................ 205
11.4.8. CPU...........................................................................................................................206
11.4.9. RS-232 Communications.............................................................................................. 206
11.4.9.1. General RS-232 Troubleshooting............................................................................. 206
11.4.9.2. Troubleshooting Analyzer/Modem or Terminal Operation.............................................207
11.5. Repair Procedures..............................................................................................................207
11.5.1. Repairing Sample Flow Control Assembly........................................................................ 207
11.5.2. Removing/Replacing the GFC Wheel............................................................................... 209
11.5.3. Disk-On-Chip Replacement Procedure.............................................................................210
12. A PRIMER ON ELECTRO-STATIC DISCHARGE.......................................................................... 213
12.1. How Static Charges are Created...........................................................................................213
12.2. How Electro-Static Charges Cause Damage ...........................................................................214
12.3. Common Myths About ESD Damage..................................................................................... 215
12.4. Basic Principles of Static Control.......................................................................................... 216
12.4.1. General Rules............................................................................................................. 216
12.4.2. Basic anti-ESD Procedures for Analyzer Repair and Maintenance........................................ 218
12.4.2.1. Working at the Instrument Rack..............................................................................218
12.4.2.2. Working at a Anti-ESD Work Bench..........................................................................218
12.4.2.3. Transferring Components from Rack To Bench and Back............................................. 219
12.4.2.4. Opening Shipments from and Packing Components for Return to Teledyne Instruments
Customer Service............................................................................................................... 219