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Troubleshooting & Repair
10.6.15. PNEUMATIC SENSOR ASSEMBLY
10.6.16. SAMPLE PRESSURE
10.6.17. IZS OPTION
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7. Check the voltages between the pairs of pins listed in Table 10-9. The result for each
pair should be equal and approximately 10% of the reading level recorded in Step 1.
Table 10-9: Example of HVPS Power Supply Outputs
If HVPS reading = 700 VDC
PIN PAIR
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8. Turn off the instrument power, and re-connect the PMT tube, and then re-assemble
the sensor.
If any faults are found in the test, the HVPS must be replaced. There are no user
serviceable parts inside the HVPS.
The pressure/flow sensor circuit board, located behind the sensor assembly, 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.
Measure the voltage across TP1 and TP2, it should be 10.0 0.25 V. If not, the board
may be faulty.
Measure the voltage across capacitor C2; it should be 5.0 ± 0.25 V. If not, the board
may be faulty.
Measure the voltage across test points TP1 and TP4. With the sample pump disconnected
or turned off, this voltage should be 4500 250 mV. With the pump running, it should be
about 0.2 V less as the sample pressure drops by about 1 in-Hg-A from ambient pressure.
If this voltage is significantly different, the pressure transducer S2 or the board may be
faulty. A leak in the sample system to vacuum may also cause this voltage to be between
about 0.6 and 4.5. Ensure that the front panel reading of the sample pressure is at about 1
in-Hg-A less than ambient pressure.
The zero/span valves and IZS options need to be enabled in the software (contact the
factory on how to do this). Refer to Figure 3-19 and Figure 3-20 for a flow diagram with
zero/span valve or IZS option.
Teledyne ML - T100 UV Fluorescence SO2 Analyzer
NOMINAL READING
70 VDC
70 VDC
70 VDC
70 VDC
70 VDC
70 VDC
70 VDC
06807A(DCNxxxx)
6
7
5
8
4
3
9
2
10
11
1
KEY
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