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Model GFC7000E Instruction Manual TROUBLESHOOTING & REPAIR PROCEDURES
04584 Rev A1 203
11.4.6.3. GFC Wheel Drive
If the D1 and D2 on the sync demodulator board are not flashing then:
1. Check for power to the motor by measuring between pins 1 and 3 on the connector feeding
the motor. For instruments configured for 120 or 220-240VAC there should be approximately
88 VAC for instruments configured for 100VAC, it should be the voltage of the AC mains,
approximately 100VAC.
2. Verify that the frequency select jumper, JP4, is properly set on the Relay Board. For 50 Hz
operation it should be installed. For 60 Hz operation may either be missing or installed in a
vertical orientation.
3. If there is power to the motor and the frequency select jumper is properly set then the motor
is likely bad. See Section 11.5.2 for instructions on removing and replacing the GFC assembly
that the motor is bolted to.
11.4.6.4. IR Source
The IR source can be checked using the following procedure:
1. Disconnect the source and check its resistance when cold. When new, the source should have
a cold resistance of more than 1.5 Ohms but less than 3.5 Ohms. If not, then the source is
bad.
2. With the source disconnected, energize the analyzer and wait for it to start operating.
Measure the drive Voltage between pins 1 and 2 on the jack that the source is normally
connected to, it should be 11.5 ± 0.25 VDC. If not, then there is a problem with either the
wiring, the Relay Board, or the +12V power supply.
3. If the drive voltage is correct in step 2, then remove the source from the heat sink assembly
(2 screws on top) and connect to its mating connector. Observe the light being emitted from
the source. It should be centered at the bottom of the U-shaped element. If there is either
no emission or a badly centered emission then the source is bad.
11.4.6.5. Pressure/Flow Sensor Assembly
The pressure/flow sensor PCA, located on the top of the absorption bench, can be checked with a
Voltmeter using the following procedure which, assumes that the wiring is intact, and that the
Motherboard and the power supplies are operating properly:
1. For Pressure related problems:
• Measure the voltage across C1 it should be 5 ± 0.25 VDC. If not then the board is bad.
• Measure the voltage across TP4 and TP1. With the sample pump disabled it should be
4500 mV ±250 mV. With the pump energized it should be approximately 200 mV less. If
not, then S1, the pressure transducer is bad, the board is bad, or there is a pneumatic
failure preventing the pressure transducer from sensing the absorption cell pressure
properly.
2. For flow related problems:
• Measure the voltage across TP2 and TP1 it should be 10 ±0.25 VDC. If not then the board
is bad.