Teledyne T703, T703U 8.5. TROUBLESHOOTING THE O3 PHOTOMETER

General Troubleshooting & Service Teledyne API T703/T703U Calibrator Operation Manual

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There are three possible causes for the Ozone Generator temperature to have failed.

 The O3 generator heater has failed. Check the resistance between pins 5 and 6 on

the 6-pin connector adjacent to the UV Lamp on the O3 Generator. It should be

approximately 5 Ohms.

 Assuming that the I2C 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 O3 PHOTOMETER

Dynamic problems are problems, which only manifest themselves when the photometer

is measuring O3 concentration gas mixtures. These can be the most difficult and time

consuming to isolate and resolve.

Since many photometer behaviors that appear to be a dynamic in nature are often a

symptom of a seemingly unrelated static problems, it is recommended that dynamic

problems not be addressed until all static problems, warning conditions and subsystems

have been checked and any problems found are resolved.

Once this has been accomplished, the following most common dynamic problems

should be checked.

 Check for leaks in the pneumatic system as described in Section 7.2

 Confirm that the Zero gas is free of Ozone.

 Confirm that the Source Lamp is fully inserted and that the lamp hold-down thumb-

screw is tight.

 Check for a dirty Absorption Cell and/or pneumatic lines. Clean as necessary as

described in Section 7.2

 Disconnect the exhaust line from the optical bench (the pneumatic line at the lamp

end of the bench) and plug the port in the bench. If readings remain noisy, the

problem is in one of the electronic sections of the instrument. If readings become

quiet, the problem is in the instrument's pneumatics.

07223C DCN6572