Teledyne gfc 7000ta Opto Pickup Assembly, GFC Wheel Drive, Nominal Measured Frequency

Troubleshooting Model GFC7000TA Carbon Dioxide Analyzer

∙If they are not then either the sync demodulator board or the IR-photodetector are bad. See Section 10.4.1.4 for problems with the IR-photodetector TEC drive.

10.5.7.2. Opto Pickup Assembly

Operation of the opto pickup PCA (04088) can be verified with a voltmeter. Measure the AC and DC voltage between digital ground on the relay board, or touchscreen and TP1 and TP2 on the sync pickup PCA. For a working board, with the GFC motor spinning, they should read 2.4 ±0.1 VAC and 2.5 ±0.15 VDC.

Further confirmation that the pickups and motor are operating properly can be obtained by measuring the frequency at TP1 and TP2 using a frequency counter, a digital volt meter with a frequency counter, or an oscilloscope per the table below.

Table 10-9: Opto Pickup Board Nominal Output Frequencies

	NOMINAL MEASURED FREQUENCY
AC MAINS FREQ.	TP1	TP2
50 Hz	25	300
60 Hz	30	360

10.5.7.3. 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 10.6.2 for instructions on removing and replacing the GFC assembly that the motor is bolted to.

10.5.7.4. 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.

Teledyne Analytical Instruments 244