General Troubleshooting & Service Teledyne API T703/T703U Calibrator Operation Manual
174
UV Lamp Temperature 8.4.12.3.
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.
Ozone Generator Temperature 8.4.12.4.
There are three possible causes for the Ozone Generator temperature to have
failed.
The O
3
generator heater has failed. Check the resistance between pins 5
and 6 on the 6-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 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 of the 6-pin connector.
8.5. TROUBLESHOOTING THE O
3
PHOTOMETER
DYNAMIC PROBLEMS WITH THE O
3
PHOTOMETER 8.5.1.
Dynamic problems are problems, which only manifest themselves when the
photometer is measuring O
3
concentration gas mixtures. These can be the most
difficult and time consuming to isolate and resolve.
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