Troubleshooting & Service T400 Ozone Analyzer Operator’s Manual
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12.6.1.2. Sample Temperature
The Sample Temperature should read approximately 5.0C higher than the box
temperature.
12.6.1.3. UV Lamp Temperature
There are three possible causes for the UV Lamp temperature to have failed.
The UV Lamp heater has failed.
Check the resistance between pins 5 and 6 on the six-pin connector adjacent to
the UV Lamp on the Optical Bench.
It should be approximately 30 Ohms.
Assuming that the I
2
C bus is working and that there is no other failure with the Relay
board, the FET Driver on the Relay Board may have failed.
Using the PHOTO_LAMP_HEATER parameter under the SIGNAL I/O function
of the DIAG menu, as described above, turn on and off the UV Lamp Heater
(D15 on the relay board should illuminate as the heater is turned on).
Check the DC voltage present between pin 1 and 2 on J13 of the Relay Board.
If the FET Driver has failed there will be no change in the voltage across pins 1
and 2.
If the FET Driver Q2 checks out OK, the thermistor temperature sensor in the lamp
assembly may have failed.
Unplug the connector to the UV Lamp Heater/Thermistor PCB, and measure
the resistance of the thermistor between pins 5 and 6 of the 6 pin connector.
The resistance near the 58
o
C set point is ~8.1k ohms.
12.6.1.4. IZS Ozone Generator Temperature (Optional)
There are three possible causes for the Ozone Generator temperature to have failed.
The O
3
Gen heater has failed.
Check the resistance between pins 5 and 6 on the six-pin connector adjacent to
the UV Lamp on the O
3
Generator.
It should be approximately 5 Ohms.
Assuming that the I
2
C bus is working and that there is no other failure with the Relay
board, the FET Driver on the Relay Board (see 12.7.6) may have failed.
Using
the O3_GEN_HEATER parameter under the SIGNAL I/O function of the
DIAG menu, as described above, turn on and off the UV Lamp Heater.
Check the DC voltage present between pin 1 and 2 on J14 of the Relay Board.
If the FET Driver has failed there should be no change in the voltage across
pins 1 and 2.
If the FET Driver checks out OK, the thermistor temperature sensor in the lamp
assembly may have failed.
Unplug the connector to the Ozone Generator Heater/Thermistor PCB, and
measure the resistance of the thermistor between pins 5 and 6.
